IRON 10-K & 10-Q changes, risk factors and insider trading

We commenced operations in 2017 and are a clinical-stage biopharmaceutical company with a limited operating history. Biopharmaceutical product development is a highly speculative undertaking and involves a substantial degree of risk. Since our inception in October 2017, we have devoted substantially all of our efforts to organizing and staffing our company, business planning, capital raising, establishing and maintaining our intellectual property portfolio, building our pipeline of product candidates, conducting drug discovery activities, undertaking preclinical studies, conducting early-stage clinical trials, preparing for the potential commercialization of bitopertin, if approved, and providing general and administrative support for these operations. We have not yet demonstrated our ability to successfully develop any product candidate, obtain regulatory approvals, manufacture a commercial-scale product or arrange for a third party to do so on our behalf, or conduct sales and marketing activities necessary for successful product commercialization. Consequently, any predictions you make about our future success or viability may not be as accurate as they could be if we had a longer operating history or a history of successfully developing and commercializing products.

Our net losses were $212.2 million, $109.4 million and $76.4 million for the years ended December 31, 2025, 2024 and 2023, respectively. We had an accumulated deficit of $298.0$510.2 million as of December 31, 2024.2025. Substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from selling, general and administrative costs associated with our operations. We expect our research and development expenses to continue to increase significantly in connection with the commencement and continuation of clinical trials of our product candidates. In addition, if we obtain regulatory approval for our product candidates, we will incur significant sales, marketing and manufacturing expenses. We also will continue to incur additional costs associated with operating as a public company and expect to continue to incur significant and increasing operating losses over the next several years and for the foreseeable future. Because of the numerous risks and uncertainties associated with developing pharmaceutical products, we are unable to predict the extent of any future losses or when we will become profitable, if at all. Even if we do become profitable, we may not be able to sustain or increase our profitability on a quarterly or annual basis.

the changing and volatile U.S. and global economic environments, including as a result of public health crisesenvironments; and future accounting pronouncements or changes in our accounting policies.

Our ability to become profitable depends upon our ability to generate revenue. To date, we have not generated collaborative revenue from our product candidates and have not generated revenue from product sales, and do not expect to generate any revenue from the sale of products in the near future.sales. We do not expect to generate significant revenue unless and until we obtain regulatory approval of, and begin to sell, one or more of our product candidates.candidates, which may take longer than we anticipate, or may not occur at all. Our ability to generate revenue depends on a number of factors, including, but not limited to, our ability to:

obtain and maintain healthcare coverage and adequate reimbursementreimbursement, if and when our product candidates are approved;

The development of pharmaceutical products is capital-intensive. We are currently advancing our hematologic disease programs through preclinical and clinical development. We expect our expenses to significantly increase in connection with our ongoing activities, particularly as we continue the research and development of, initiate and complete clinical trials of, and seek regulatory approval for, our product candidates. In addition, depending on the status of regulatory approval or, if we obtain regulatory approval for any of our product candidates, we expect to incur significant commercialization expenses related to product sales, marketing, manufacturing and distribution. We may also need to raise additional funds sooner if we choose to pursue additional indications and/or geographies for our current or future product candidates or otherwise expand more rapidly than presently anticipated. Furthermore, we expect to continue to incur costs associated with operating as a public company. Accordingly, we may need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we may be forced to delay, reduce or eliminate certain of our research and development programs or future commercialization efforts.

We believe that our cash, cash equivalents and marketable securities, including the net proceeds of our January 2025 underwritten public offering,securities will enablebe ussufficient to fund our current operating expenses and capital expenditure requirementsplans and our debt service obligations into 2028,2029, without taking into account any potential net cash inflows from bitopertin or any other marketed product, if approved during such period. However, we have based this estimate on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than expected. Our future capital requirements will depend on and could increase significantly as a result of many factors, including:

establishingthe terms of agreements with third-party manufacturers for supply of product candidate components for our clinical trials;

commercializing product candidates, if and when approved, whether alone or in collaboration with others; and obtaining and maintaining third-party insurance coverage and adequate reimbursement for any approved products.

We have not yet progressed any product candidates intothrough a Phase 3 clinical trial and may be unable to successfully complete any additional clinical trials for any product candidates we develop. Certain of our programs are still in preclinical development and may never advance to clinical development.

We currently have only three product candidates in clinical development, none of which has yet progressed intothrough a completed Phase 3 clinical trial. As such, we have not yet demonstrated our ability to successfully complete large-scale, pivotal clinical trials, obtain regulatory approvals, manufacture a commercial scale product or arrange for a third party to do so on our behalf or conduct sales and marketing activities necessary for successful commercialization. The majority of our programs are still in preclinical and early to mid-stage clinical development. Our clinical programs may not advance to the next stage of clinical development, and our preclinical programs may never advance to clinical development or through clinical development, as applicable. We may not initiate any clinical trial of our product candidates until we have submitted an IND to the FDA or comparable submissions with equivalent regulatory authorities and received regulatory clearance. We may not be able to submit INDs or other regulatory filings for bitopertin or any of our other product candidates on the timelines we expect, if at all. For example, we may experience manufacturing delays or other delays with IND-enabling studies. Moreover, we cannot be sure that submission of regulatory filings with the FDA or other regulatory authorities will result in such regulatory authorities allowing clinical trials to begin on a timely basis or at all, or that, once begun, such trials will be completed on schedule, if at all, or that issues will not arise that require us to revise, postpone, suspend or terminate our clinical trials. For example, we filed an IND in April 2022 with the FDA to initiate the AURORA Phase 2 trial of bitopertin in EPP patients, but the FDA initially placed the initiation of this trial on clinical hold; we received clearance to initiate the study in July 2022 after the study design was finalized with the FDA, and we initiated the study in October 2022. Commencing any of our clinical trials is subject to finalizing the trial design based on discussions with the FDA and other regulatory authorities. Any guidance we receive from the FDA or other regulatory authorities is subject to change. TheseThe outcomes of our interactions with these regulatory authorities, including interactions critical to successfully advancing through the different phases of clinical development, such as end-of-phase 2 meetings with the FDA, may be difficult to predict ahead of time. In particular, regulatory authorities could change their position, including on the acceptability of our trial designs or the clinical endpoints selected, which may require us to complete additional clinical trials or result in the composition of stricter approval conditions than currently expected. ForOur a further example, we relied on the data package generated by F. Hoffmann-La Roche Ltd. and Hoffmann-La Roche Inc., or collectively, Roche,ability to supportsuccessfully ouradvance IND submission for bitopertin to initiate our AURORA Phase 2 clinical trial in patients with EPP, as well as our submission of an application with the Australian Therapeutic Goods Administration, or TGA, for our BEACON Phase 2 clinical trial in patients with EPP or XLP, and it is possible that the FDA or TGA, as applicable, may require us to conduct additionalfrom preclinical studies tothrough supportthe adifferent future marketing applicationphases of bitopertin.clinical development is therefore subject to significant uncertainty. Successful completion of our clinical trials is a prerequisite to submitting an NDA or a BLA to the FDA, a Marketing Authorisation Application, or MAA, to the European Medicines Agency, or EMA, or other marketing applications to regulatory authorities in other jurisdictions, for each product candidate and, consequently, the regulatory approval of each product candidate.

A single well-controlled clinical trial may not be sufficient for approval. In general,Historically, the FDA requireshas generally required two well-controlled clinical trials to support registration of a new drug or biologic.biologic, Exceptionsalthough mayexceptions behave been made in cases of a severe disease with few treatment options, and in principle this exception may appear applicable to many of the diseases that we seek to treat, such as EPP, XLP, anemia of MF, DBA and others. More recently, the FDA has indicated that its default position will be that one well-controlled clinical trial, combined with confirmatory evidence, will serve as the basis of marketing authorization of novel products. Nonetheless, the FDA and other regulators may always require additional clinical trials to support regulatory approval.

The discovery and development of therapeutics for patients with hematologic diseases is an emerging field, and the scientific discoveries that form the basis for our efforts to discover and develop product candidates are relatively new. The scientific evidence to support the feasibility of developing product candidates based on these discoveries is both preliminary and limited. Although we believe, based on our preclinical work and clinical results to date, that our programs have the potential to provide disease-modifying therapies, future clinical results may not confirm this hypothesis or may only confirm it for certain alterations or certain indications. The patient populations for our product candidates are limited to those with specific hematologic diseases. We cannot be certain that the patient populations for each specific disease will be large enough to allow us to successfully obtain approval for and commercialize our product candidates and achieve profitability.

Clinical product development involves a lengthy and expensive process, with an uncertain outcome.

Additionally, some of the clinical trials we conduct, such as our completed BEACON Phase 2 clinical trial of bitopertin andbitopertin, our ongoing RALLY-MF Phase 2 clinical trial of DISC-0974, and our ongoing clinical trials of DISC-3405, may be open-label in study design and may be conducted at a limited number of clinical sites on a limited number of patients. An “open-label” clinical trial is one where both the patient and investigator know whether the patient is receiving the investigational product candidate or either an existing approved drug or placebo. Most typically, open-label clinical trials test only the investigational product candidate and sometimes may do so at different dose levels. Open-label clinical trials are subject to various limitations that may exaggerate any therapeutic effect as patients in open-label clinical trials are aware when they are receiving treatment. Open-label clinical trials may be subject to a “patient bias” where patients perceive their symptoms to have improved merely due to their awareness of receiving an experimental treatment. In addition, open-label clinical trials may be subject to an “investigator bias” where those assessing and reviewing the physiological outcomes of the clinical trials are aware of which patients have received treatment and may interpret the information of the treated group more favorably given this knowledge. The results from an open-label clinical trial may not be predictive of future clinical trial results when studied in a controlled environment with a placebo or active control.

In May 2021, we entered into a license agreement with Roche, or the Roche Agreement, pursuant to which, among other things, Roche granted us an exclusive and sublicensable (subject to Roche’s consent, except with respect to affiliates) worldwide license under certain of Roche’s patent rights and know-how to develop and commercialize bitopertin. Although bitopertin was originally evaluated by Roche in over 4,000 individuals, Roche did not evaluate bitopertin in EPP or XLP, so the safety data generated from Roche’s clinical trials of bitopertin may not be predictive or indicative of the results of our clinical trials. Regulatory authorities may also raise questions regarding the transition in the future from Roche-manufactured drug substance to drug substance manufactured by us or another party, and we may be required to conduct comparability assessments, which could result in delays in development and additional costs. We may face similar challenges with respect to our other product candidates, for which preclinical results or prior clinical trial results may not be indicative or predictive of future clinical trial results.

Even if the FDA does find our clinical trial success criteria to be sufficiently supported and clinically meaningful at the time, we may not achieve the pre-specified endpoint to a degree of statistical significance in any pivotal or other clinical trials we may conduct for our product candidates. Further, even if we do achieve the pre-specified criteria, our trials may produce results that are unpredictable or inconsistent with the results of the more traditional efficacy endpoints in the trial. For example, in the Complete Response Letter, or CRL, that the FDA issued in February 2026 with respect to our NDA for accelerated approval of bitopertin in EPP and XLP, the FDA agreed that clinical data from our AURORA and BEACON clinical trials provided sufficient evidence that bitopertin significantly lowers whole blood metal-free PPIX, but concluded that the trials did not show evidence of association between percent change in PPIX and sunlight exposure-based endpoints as measured in the trials. As such, the FDA determined that there is uncertainty regarding whether bitopertin’s effect on PPIX is reasonably likely to predict clinical benefit, despite the strong mechanistic and biological plausibility supporting the use of the PPIX biomarker in protoporphyria. As a result, the FDA did not approve our NDA and indicated instead that we would need to provide evidence of clinical benefit from an additional trial, such as our ongoing APOLLO trial, to support a potential traditional approval. The FDA also could change its view or give overriding weight to other efficacy endpoints over a primary endpoint, even if we achieve statistically significant results on that primary endpoint, if for example we do not do so on our secondary efficacy endpoints. The FDA also weighs the benefits of a product candidate against its risks and the FDA may view the efficacy results in the context of safety as not being supportive of approval. Other regulatory authorities in Europe and other countries may make similar findings with respect to these endpoints.

From time to time, we may publicly disclose interim, top-line, initial or preliminary data from our clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data. For example, we announced initial data from our RALLY-MF Phase 1b/2 DISC-0974 trial in patients with anemia of MF in December 2023, June 2024, and December 2024, and from our Phase 1b DISC-0974 trial in patients with anemia and NDD-CKD in December 2023 and October 2024. We also announced initial data from the SAD portion of the Phase 1 clinical trial of DISC-3405 in healthy volunteers in June 2024.2025. We also may make assumptions, estimations, calculations and conclusions as part of our analyses of data, and may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the interim, top-line, initial or preliminary results that we report may differ from future results of the same trials, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Interim, top-line, initial and preliminary data from clinical trials are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. Interim, top-line, initial and preliminary data also remain subject to audit and verification procedures that may result in the final data being materially different from the interim, top-line, initial or preliminary data we previously published. As a result, interim, top-line, initial and preliminary data should be viewed with caution until the final data are available. Adverse differences between interim, top-line, initial or preliminary data and final data could significantly harm our business prospects and may cause the price of our common stock to fluctuate or decline.

Any results from early preclinical studies and clinical trials of bitopertin, DISC-0974, DISC-0998, DISC-3405 or our other product candidates or programs may not necessarily be predictive of the results from later preclinical studies and clinical trials. For example, we havepreviously announced positive data from our Phase 2 BEACON and AURORA clinical trials of bitopertin in patients with EPP, but there can be no assurance that our Phase 3 APOLLO clinical trial of bitopertin in patients with EPP will be successful or that the results of our APOLLO clinical trial will support a traditional approval of bitopertin for EPP. In addition, we previously announced positive initial data from aour RALLY-MF Phase 1b/2 clinical trial of DISC-0974 in patients with non-dialysisanemia dependentof CKD and anemia.MF. However, there can be no assurance that DISC-0974 will achieve the desired effects in this indication. Additionally,Further, we announced positive results from a Phase 1 clinical trial of DISC-3405 in healthy adult volunteers in December 2024,2024 and June 2025, which may not be indicative or predictive of future clinical trial results. Similarly, even if we are able to complete our planned preclinical studies and clinical trials of our product candidates according to our current development timeline, the results from such preclinical studies and clinical trials of our product candidates may not be replicated in subsequent preclinical studies or clinical trial results.

Before obtaining regulatory approvals for the commercial sale of any products, we must demonstrate through lengthy, complex and expensive preclinical studies and clinical trials that our product candidates regulated as drugs are safe and effective and our product candidates regulated as biologics are safe, pure and potent for use in each target indication. Clinical testing is expensive and can take many years to complete, and outcomes are inherently uncertain. Failure can occur at any time during the clinical trial process. Because the majority of our programs and product candidates are in an early or intermediate stage of development, there is a high risk of failure, and we may never succeed in developing any marketable products. There is typically an extremely high rate of attrition from the failure of product candidates proceeding through clinical trials. Product candidates in later stages of clinical trials also may fail to show the desired safety and efficacy profile despite having progressed through preclinical studies and initial clinical trials. For example, Roche had previously developed bitopertin as a potential therapy for certain symptoms of schizophrenia and obsessive-compulsive disorder, but discontinued the program for lack of efficacy in those indications after completing over 30 clinical trials in over 4,000 individuals. If the results of our ongoing or future preclinical studies and clinical trials are inconclusive with respect to the safety and efficacy of our programs and product candidates, if we do not meet the clinical endpoints with statistical and clinically meaningful significance, or if there are safety concerns associated with our product candidates, we may be prevented from, or delayed in, obtaining regulatory approval for such product candidates. In some instances, there can be significant variability in safety or efficacy results between different clinical trials of the same product candidate due to numerous factors, including changes in trial procedures set forth in protocols, differences in the size and type of the patient populations, changes in and adherence to the clinical trial protocols and the rate of dropout among clinical trial participants. Results of our trials could reveal a high and unacceptable severity and prevalence of side effects. In such an event, our trials could be suspended or terminated, and the FDA or comparable foreign regulatory authorities could order us to cease further development of or deny approval of our product candidates for any or all targeted indications. Treatment-related side effects could also affect patient recruitment or the ability of enrolled patients to complete the trial or result in potential product liability claims.

As is the case with many treatments for hematologic and rare diseases, it is likely that there may be side effects associated with the use of our product candidates. If significant adverse events or other side effects are observed in any of our current or future clinical trials, we may have difficulty recruiting patients to our clinical trials, patients may drop out of our trials, or we may be required to abandon the trials or development efforts of one or more product candidates altogether. We, the FDA or other applicable regulatory authorities, or an IRB may suspend or terminate clinical trials of a product candidate at any time for various reasons, including a belief that subjects in such trials are being exposed to unacceptable health risks or adverse side effects. Further, undesirable side effects in one of our clinical trials for a product candidate in one indication could adversely affect enrollment in clinical trials, regulatory approval and commercialization of such product candidate in other indications. Even if the side effects do not preclude the product from obtaining or maintaining regulatory approval, undesirable side effects may inhibit market acceptance of the approved product due to its tolerability versus other therapies. Any of these developments could materially harm our business, operating results, financial condition and prospects.

We have conducted and are currently conducting clinical trials for bitopertin in Australiabitopertin, and may in the future conduct additional clinical trials of our product candidatescandidates, outside the United States, and the FDA and comparable foreign regulatory authorities may not accept data from such trials.

We conducted BEACON, our Phase 2 open-label, parallel-dose clinical trial of bitopertin in EPP and XLP patients, at sites in Australia. All participants inwho completed BEACON arewere eligible to participate in HELIOS, an open-label, long-term extension study of bitopertin in EPP and XLP patients, that we are also conducting in Australia. We are also planning to conductconducting APOLLO, a Phase 3, randomized, double-blind, placebo-controlled clinical trial of bitopertin in EPP and XLP patients, in Canada, Europe and Australia, as well as the United States. We may in the future choose to conduct additional clinical trials of our product candidates outside the United States, including in Europe, Australia, or other foreign jurisdictions. The acceptance of trial data from clinical trials conducted outside the United States by the FDA may be subject to certain conditions. In cases where data from clinical trials conducted outside the United States are intended to serve as the sole basis for regulatory approval in the United States, the FDA will generally not approve the application on the basis of foreign data alone unless (i) the data are applicable to the United States population and United States medical practices, (ii) the trials were performed by clinical investigators of recognized competence and (iii) the data may be considered valid without the need for an on-site inspection by the FDA or, if the FDA considers such an inspection to be necessary, the FDA is able to validate the data through an on-site inspection or other appropriate means. Additionally, the FDA’s clinical trial requirements, including sufficient size of patient populations and statistical powering, must be met. Many foreign regulatory bodies have similar approval requirements. In addition, such foreign trials will be subject to the applicable local laws of the foreign jurisdictions where the trials are conducted. There can be no assurance that the FDA or any comparable foreign regulatory authority, will accept data from trials conducted outside of the United States or the applicable jurisdiction. If the FDA or any comparable foreign regulatory authority does not accept such data, it would result in the need for additional trials, which would be costly and time-consuming and delay aspects of our business plan, and which may result in our product candidates not receiving regulatory approval or clearance for commercialization in the applicable jurisdiction.

The process of obtaining regulatory approvals, both in the United States and abroad, is expensive and often takes many years. If the FDA or a comparable foreign regulatory authority requires that we perform additional preclinical studies or clinical trials, approval may be delayed, if obtained at all. The length of such a delay varies substantially based upon a variety of factors, including the type, complexity and novelty of the product candidate involved. Changes in regulatory approval policies during the development period, changes in or enactment of additional statutes or regulations, or changes in regulatory review policies for each submitted NDA, BLA, or equivalent application types, may cause delays in the approval or rejection of an application. The FDA and comparable foreign regulatory authorities have substantial discretion in the approval process and may refuse to accept any application for review. Even if the FDA or a comparable foreign regulatory authority accepts an application for review, we can provide no assurance that an accepted application will ultimately result in an approval. Any guidance we receive from the FDA or other comparable regulatory authorities during the development or marketing application review processes is subject to change. As such, the outcomes of our interactions with such regulatory authorities during such review processes, such as pre-NDA or Type A meetings with the FDA, and the ultimate approval decision, are subject to significant uncertainty. Among other things, the FDA or a comparable foreign regulatory authority may decide that our data is insufficient for approval and require additional preclinical, clinical or other studies. Our product candidates could be delayed in receiving, or fail to receive, regulatory approval for many reasons, including the following:

The incidence and prevalence for the target patient populations of our programs and product candidates have not been established with precision. Our lead heme biosynthesis modulation product candidate, bitopertin, is an oral, selective inhibitor of GlyT1. We are initially focused on developing bitopertin for the treatment of EPP and XLP, which are both diseases marked by severe photosensitivity and damage to the hepatobiliary system caused by the accumulation of PPIX. We are initially focused on developing DISC-0974 for anemia of MF and anemia of non-dialysisinflammatory dependentbowel CKD.disease, or IBD. We are initially focused on developing DISC-3405 for the treatment of PV.PV and sickle cell disease, or SCD. Our projections of both the number of people who have these diseases, as well as the subset of people with these diseases who have the potential to benefit from treatment with our programs and product candidates, are based on our estimates.

The total addressable market opportunity will ultimately depend upon, among other things, the diagnosis criteria included in the final label, the indications for which our product candidates are approved for sale, acceptance by the medical community and patient access, product pricing and reimbursement. The number of patients with erythropoieticEPP, porphyria andXLP, anemias of inflammationMF or IBD, PV, SCD, or other indications for which our product candidates may be approved as treatment may turn out to be lower than expected, patients may not be otherwise amenable to treatment with our products, or new patients may become increasingly difficult to identify or gain access to, all of which would adversely affect our results of operations and our business. We may not be successful in our efforts to identify additional product candidates. Due to our limited resources and access to capital, we must prioritize development of certain product candidates, which may prove to be the wrong choice and may adversely affect our business.

AlthoughWe wedo designednot ourhave ongoingthe ability to independently conduct clinical trials. We have relied on and expect to continue to rely on medical institutions, clinical investigators, contract laboratories and other third parties, such as CROs, to conduct or otherwise support the Phase 1b/2 clinical trials of DISC-0974 and our ongoing Phase 2 clinical trial of bitopertin, are designing our planned3 APOLLO clinical trial of bitopertin andin our planned Phase 2 clinical trial of DISC-3405,EPP and intendXLP, toas designwell other futureas clinical trials for our other product candidates, these trials are or will be conducted by CROs and we expect CROs will conduct all of our future clinical trials.candidates. As a result, many important aspects of our development programs, including their conduct and timing, are outside of our direct control. Our reliance on third parties to conduct future clinical trials also results in less direct control over the management of data developed through clinical trials than would be the case if we were relying entirely upon our own staff. Communicating with outside parties can also be challenging, potentially leading to mistakes as well as difficulties in coordinating activities. Outside parties may:

These factors may materially adversely affect the willingness or ability of third parties to conduct our clinical trials and may subject us to unexpected cost increases that are beyond our control. If the principal investigators or CROs do not perform clinical trials in a satisfactory manner, breach their obligations to us or fail to comply with regulatory requirements, or if any of our relationships with these third-party principal investigators or CROs terminate, the development, regulatory approval and commercialization of our product candidates may be delayed, we may not be able to obtain regulatory approval and commercialize our product candidates or our development program may be materially and irreversibly harmed. If we are unable to rely on clinical data collected by our principal investigators or CROs, we could be required to repeat, extend the duration of, or increase the size of any clinical trials we conduct and this could significantly delay commercialization and require significantly greater expenditures.

We do not currently own or operate, nor do we have any plans to establish in the future, any manufacturing facilities. AlthoughAs such, we believe we have obtained sufficient material to produce bitopertin tablets to complete our ongoing Phase 2 clinical trial, and DISC-0974 vials to complete our ongoing Phase 1b/2 clinical trials, we cannot be sure we have correctly estimated our drug product and API requirements or that such drug product or API will not expire before we want to use it. We rely, and expect to continue to rely, on third parties such as contract development and manufacturing organizations, or CDMOs, for the manufacture of our product candidates for preclinical development and clinical testing. We also expect to rely on third parties for the commercial manufacture of our products if any of our product candidates receive regulatory approval. This reliance on third parties increases the risk that we will not have sufficient quantities of our product candidates or products or such quantities at an acceptable time, cost or quality, which could delay, prevent or impair our development or commercialization efforts.

If any CDMO with whom we contract fails to perform its obligations, we may be forced to enter into an agreement with a different CDMO, which we may not be able to do on reasonable terms, if at all. In such a scenario, our clinical trials supply could be delayed significantly as we establish alternative supply sources. In some cases, the technical skills required to manufacture our product candidates may be unique or proprietary to the original CDMO and we may have difficulty, or there may be contractual restrictions prohibiting us from, transferring such skills to a back-up or alternate supplier, or we may be unable to transfer such skills at all. In addition, if we are required to change CDMOs for any reason, we will be required to verify that the new CDMO maintains facilities and procedures that comply with quality standards and with all applicable regulations. We will also need to verify, such as through a manufacturing comparability study, that any new manufacturing process will produce our product candidate according to the specifications previously submitted to the FDA or another regulatory authority. The delays associated with the verification of a new CDMO could negatively affect our ability to develop product candidates or commercialize our products in a timely manner or within budget. In addition, changes in manufacturers often involve changes in manufacturing procedures and processes, which could require that we conduct bridging studies between our prior clinical supply used in our clinical trials and that of any new manufacturer. We may be unsuccessful in demonstrating the comparability of clinical supplies which could require the conduct of additional clinical trials.

Any performance failure on the part of our existing or future manufacturers could delay clinical development or regulatory approval. If our current CDMOs cannot perform as agreed, we may be required to replace such CDMOs. In addition, there has been increased governmental focus in the U.S. on contracting with Chinese companies for the development or manufacturing of pharmaceutical products. For example, therelegislation have been Congressional legislative proposals, such as the bill titled the BIOSECURE Act that was previously considered (and not enacted)pending in Congress, whichCongress would have, among other things, prohibitedprohibit U.S. federal funding in connection with biotechnology equipment or services produced or provided by certain named Chinese “biotechnology companies of concern” (which includes WuXi AppTech (Hong Kong) Limited and its affiliates, or WuXi) and loans and grants to, and federal contracts with any entity that uses biotechnology equipment or services from one of these entities. The legislation would also have givengive the federal government the authority to name additional “biotechnology companies of concern” that are engaged in research activities with the Chinese government and that pose a risk of U.S. national security. In addition, in 2025, the United States imposed substantial tariffs on imports from China as well as on other trading partners, including Canada, Mexico, and the EU. We currently rely on certain foreign or foreign-owned third-party vendors, including WuXi and its affiliates,vendors to manufacture certain materials used in clinical trials of our product candidates or to provide services in connection with certain clinical trials or certain discovery activities. Our engagement with these foreign and foreign-owned vendors may be subject to newadditional U.S. legislation similar to the proposed BIOSECURE Act,legislation, investigations, sanctions, further escalation of tariffs, trade restrictions and other foreign regulatory requirements, which could cause us to need to identify alternate service providers, increase the cost or reduce the supply of materials available to us, delay the procurement or supply of these materials, delay or impact clinical trials, or have an adverse effect on our ability to secure significant commitments from governments to purchase our potential therapies, any of which could adversely affect our financial condition and business prospects. We continue to assess the legislation and the tariffs as itthey developsdevelop to determine the effect, if any, on our contractual relationships.

The active pharmaceutical ingredients, or API, used in certain of our product candidates are supplied to us from single-source suppliers. Our ability to successfully develop oursuch product candidates, and to ultimately supply ourany resulting commercial products in quantities sufficient to meet the market demand, depends in part on our ability to obtain the API for these products in accordance with regulatory requirements and in sufficient quantities for clinical testing and commercialization. We do not currently have arrangements in place for a redundant or second-source supply of any such API in the event any of our current suppliers of such API cease their operations for any reason. We are also unable to predict how changing global economic conditions or potential global health concerns or crises will affect our third-party suppliers and manufacturers. Regional issues may in some cases accentuate these risks. For example, the pharmaceutical industry generally, and in some instances we or other third parties on which we rely, depend on China-based suppliers or service providers for certain raw materials, products and services, or other activities. Our ability or the ability of our collaborators or such other third parties to continue to engage these China-based suppliers or service providers for certain preclinical research programs and clinical development programs could be restricted due to geopolitical developments between the United States and China, including as a result of the further escalation of tariffs or other trade restrictions or if the previously proposed federal legislation knownthat aswould theprohibit BIOSECUREU.S. Actfederal funding in connection with biotechnology equipment or services produced or provided by certain named Chinese “biotechnology companies of concern” or a similar law were to be enacted. Any negative impact of such matters on our third-party suppliers and manufacturers may also have an adverse impact on our results of operations or financial condition.

For all of our product candidates, we intend to identify and qualify additional manufacturers to provide such API prior to submission of an NDA to the FDA and/or an MAA to the EMA.API. We are not certain, however, that our single-source suppliers will be able to meet our demand for their products, either because of the nature of our agreements with those suppliers, our limited experience with those suppliers or our relative importance as a customer to those suppliers. It may be difficult for us to assess our ability to timely meet our demand in the future based on past performance. While our suppliers have generally met our demand for their products on a timely basis in the past, they may subordinate our needs in the future to their other customers.

Establishing additional or replacement suppliers for the API used in our product candidates, if required, may not be accomplished quickly. If we are able to find a replacement supplier, such replacement supplier would need to be qualified and may require additional regulatory inspection or approval, which could result in further delay. While we seek to maintain adequate inventory of the API used in our product candidates, any interruption or delay in the supply of components or materials, or our inability to obtain such API from alternate sources at acceptable prices in a timely manner could impede, delay, limit or prevent our development and commercialization efforts, which could harm our business, results of operations, financial condition and prospects.

In addition, thereThere are risks associated with large scale manufacturing for clinical trials or commercial scale including, among others, cost overruns, potential problems with process scale-up, process reproducibility, stability issues, compliance with good manufacturing practices, lot consistency and timely availability of components and raw materials. Even if we obtain regulatory approval for any of our current product candidates or any future product candidates, there is no assurance that our manufacturers will be able to manufacture the approved product to specifications acceptable to the FDA or other comparable foreign regulatory authorities, to produce it in sufficient quantities to meet the requirements for the potential commercial launch of thesuch product or to meet potential future demand. If our manufacturers are unable to produce sufficient quantities for clinical trials or for commercialization, our development and commercialization efforts would be impaired, which would have an adverse effect on our business, financial condition, results of operations and growth prospects.

We are a clinical-stage biopharmaceutical company focused on the discovery, development, and commercialization of novel treatments for patients suffering from serious hematologic diseases. We have assembled a portfolio of clinical and preclinical product candidates that aim to modify fundamental biological pathways associated with the formation and function of red blood cells, specifically heme biosynthesis and iron homeostasis. Our current pipeline includes bitopertin for the treatment of erythropoietic porphyrias, or EPs, including erythropoietic protoporphyria, or EPP, and X-linked protoporphyria, or XLP, and Diamond-Blackfan Anemia, or DBAXLP; DISC-0974 for the treatment of anemia of myelofibrosis, or MF, and anemia of chronicinflammatory kidneybowel disease, or CKDIBD; and DISC-3405 (formerly MWTX-003) for the treatment of polycythemia vera, or PV, sickle cell disease, or SCD, and other hematologic disorders. In addition, our preclinical programs also include DISC-0998 for the treatment of anemia associated with inflammatory diseases. Our approach to product candidate development leverages well-understood molecular mechanisms that have been validated in humans. We believe that each of our product candidates, if approved, has the potential to improve the lives of patients suffering from hematologic diseases.

DISC-0974 is the lead product candidate in our iron homeostasis portfolio and was licensed from AbbVie Deutschland GmbH & Co. KG, or AbbVie. DISC-0974 is designed to suppress hepcidin production and increase serum iron levels. We completed a Phase 1 clinical trial in healthy volunteers in the U.S.United States in June 20222022, with results showing an acceptable tolerability profile and evidence of target engagement, iron mobilization and augmented erythropoiesis. We initiated a Phase 1b/2 clinical trial in June 2022 in patients with anemia of MF, and initiated a separate Phase 1b/2 clinical trial in February 2023 in patients with non-dialysis dependent CKD and anemia. We presented interim dataresults from both of these trials in December 2023 as well as additional interim data for anemia of MF in June 2024 and non-dialysis dependent CKD and anemia in October 2024, which additional interim data included safety data and changes in hepcidin, iron, and hemoglobin levels for additional patients, as well as longer follow-up. In December 2024, we presented additional analyses of the Phase 1b studyportion of this clinical trial showing substantial and sustained reductions in anemiahepcidin of MFlevels and increases in iron alongside strong hematologic responses across patient types and an acceptable tolerability profile. We initiated RALLY-MF, the open-label Phase 2 portion of this clinical trialtrial, in patientsDecember with2024 anemiaand of MF. We expect to reportreported initial data from this Phase 2 trial in theDecember second2025, halfwith results demonstrating meaningful overall anemia responses across all patient subgroups, regardless of 2025.baseline Wetransfusion alsostatus expectand toindependent reportof concomitant Janus Kinase, or JAK, inhibitor therapy use. Topline data from the multiple-ascending dose, or MAD, portion of the Phase 1bthis trial inis patients with non-dialysis dependent CKD and anemiaexpected in the second half of 2025.2026, which, if positive, is expected to support discussions with regulatory agencies on the potential regulatory path for DISC-0974 in anemia of MF. We areinitiated alsoa planningPhase additional2 trialsclinical trial of DISC-0974 in otherpatients anemiaswith IBD and anemia in the first quarter of inflammation.2026, In addition,and we are planning exploratory studies in additional patient populations with anemia of chronic disease. We are also developing a preclinical anti-hemojuvelin, or HJV, monoclonal antibody, DISC-0998, which also targets hepcidin suppression and was licensed from AbbVie. DISC-0998 is designed to increase serum iron levels and has an extended serum half-life as compared to DISC-0974. We believe this profile may be desirable in certain subsets of patients with anemia associated with inflammatory diseases.

Lastly,In addition, we are developing DISC-3405, a monoclonal antibody against Transmembrane Serine Protease 6, or TMPRSS6, that we licensed from Mabwell Therapeutics, Inc., or Mabwell. DISC-3405 is part of our iron homeostasis portfolio and is designed to induce hepcidin production and reduce serum iron levels. AnWe IND for DISC-3405 was cleared by the FDA, andinitiated a Phase 1 clinical trial of DISC-3405 in healthy adult volunteers was initiated in October 2023.2023 Interimand presented interim data was presented from the single-ascending dose, or SAD, portion of the Phase 1this clinical trial of DISC-3405 in healthy volunteers in June 2024. We presented data from the MADmultiple ascending dose, or MAD, portion of thethis Phaseclinical 1 healthy volunteer study of DISC-3405trial in December 2024.2024, and presented updated data from both the SAD and MAD portions of this clinical trial in June 2025, with results showing an acceptable tolerability profile and evidence of target engagement, including dose-related increases in serum hepcidin and corresponding reductions in serum iron across all dose levels. We expectare to developdeveloping DISC-3405 for the treatment of PVPV, SCD, and other hematologic disorders,disorders. andWe planinitiated toRESTORE-PV, initiatean aopen-label Phase 2 clinical trial of DISC-3405 in PVpatients with PV, in the first half of 2025.2025, with initial data expected in the second half of 2026. We also initiated a Phase 1b, open-label clinical trial of DISC-3405 in patients with SCD in October 2025, with initial data expected in the second half of 2026, and plan to explore the role of therapeutic iron restriction in other indications.

As of December 31, 2024, we had cash, cash equivalents and marketable securities of $489.9 million. In JanuaryOctober 2025 we completed an underwritten offering of shares of our common stock and pre-funded warrants for net proceeds of approximately $243.3$211.0 million, after deducting estimated offering expensesexpenses. payableAs byof us.December 31, 2025, we had cash, cash equivalents and marketable securities of $791.2 million. We believe that our cash, cash equivalents and marketable securities, including the net proceeds of our January 2025 underwritten public offering, will be sufficient to fund our current operating and capital expenditure plans and our debt service obligations into 2028,2029, without taking into account any potential net cash inflows from bitopertin or any other marketed product, if approved during such period. We have based these estimates on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. See "Liquidity and Capital Resources" for additional details.

We expect that our research and development expenses will increase substantially as we advance our programs into and through clinical development. At this time, we cannot accurately estimate or know the nature, timing andor costs of the efforts that will be necessary to complete thetheir preclinical and clinical developmentdevelopment. of any product candidates we may develop. A changeChanges in the outcome of any number of variables with respect to productthese candidates we may developprograms could significantly changeaffect the costs and timing associated with thetheir development of that product candidate.development. We may never succeed in obtaining regulatory approval for any product candidates wethat mayhave develop.not yet been approved. The successful development of any product candidate is highly uncertain. This isuncertain due to the numerous risks and uncertainties associatedinherent within product development, including the following:

We anticipate that our selling, general and administrative expenses will increase substantially in the future as we increase our headcount to support our continued research and development and potential commercialization activitiesactivities, including establishing a sales, marketing and distributionthe infrastructure to commercialize any product candidates for which we may obtain marketing approval.

Interest income primarily consists of interest earned on cash equivalents, consisting of money market funds, U.S. treasury securities and certificatescorporate ofdebt deposit,securities, as well as marketable securities, consisting of U.S treasury securities andsecurities, U.S. government agency securities and corporate debt securities.

Research and development expenses were $170.6 million for the year ended December 31, 2025, compared to $96.7 million for the year ended December 31, 2024, compared to $69.3 million for the year ended December 31, 2023.2024. The increase of $27.4$74.0 million was primarily due to an $11.9increase of $30.7 million in bitopertin development expense consisting of a $10.0 million milestone payment triggered by the initiation of our APOLLO trial and a $20.7 million increase in personnel-relatedongoing costs associated with both the APOLLO study and the HELIOS long-term extension trial. Personnel-related costs increased $19.6 million related to higher research and development headcount, including an increase of $5.3$9.0 million in stock-based compensation driven by awards granted under our equity compensation plans. Further, externalDISC-0974 development expenses increased $10.8$10.6 million primarily due to clinical trial advancement and $7.8drug manufacturing activities. Other research programs and expenses increased $9.2 million related to advancingexpanded research initiatives and ongoing program support. Additionally, DISC-3405 development expenses increased $3.8 million driven by a $10.0 million milestone payment triggered by the first administration to a patient in a Phase 2 clinical trialstrial, andpartially drugoffset by a decrease of $6.2 million related to manufacturing activitycosts forincurred bitopertinin andthe DISC-0974,year respectively.ended December 31, 2024 that did not recur in the year ended December 31, 2025.

Selling, general and administrative expenses were $65.4 million for the year ended December 31, 2025, compared to $33.0 million for the year ended December 31, 2024, compared to $21.9 million for the year ended December 31, 2023.2024. The increase of $11.2$32.3 million was primarily due to an increase of $8.9$17.5 million in personnel-related costs due to higher selling, general and administrative headcount, including an increase of $6.0$8.6 million in stock-based compensation driven by awards granted under our equity compensation plans. There was also a $13.1 million increase in legal, consulting, and professional fees primarily related to developing our commercialization capabilities.

Other income (expense), net was $24.2 million for the year ended December 31, 2025, compared to $20.7 million for the year ended December 31, 2024, compared to $14.8 million for the year ended December 31, 2023.2024. The changeincrease of $5.9$3.5 million was primarily due to an increase inhigher interest income baseddriven onby increases in ourlarger cash, cash equivalents and marketable securities balances.balances, partially offset by an increase in interest expense associated with our term loan.

Income tax expense was $0.4 million for the yearyears ended December 31, 2025 and 2024, comparedrespectively. to $0.1 million for the year ended December 31, 2023. TheThis expense primarily relates to state income tax resulting from an increase in interest income.

We have incurred significant operating losses since inception and, as of December 31, 2024,2025, had an accumulated deficit of $298.0$510.2 million. In addition, we expect to continue to incur significant and increasing expenses and operating losses for the foreseeable future. We believe that our cash, cash equivalents and marketable securities, including the net proceeds of our January 2025 underwritten public offering,securities will be sufficient to fund our current operating and capital expenditure plans and our debt service obligations into 2028,2029, without taking into account any potential net cash inflows from bitopertin or any other marketed product, if approved during such period. We have based these estimates on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. We may also pursue additional cash resources through public or private equity offerings, collaborations or additional debt financings.financing.

During the year ended December 31, 2024,2025, net cash used in operating activities of $93.9$180.4 million was primarily due to our net loss of $109.4$212.2 million, offset by changes in operating assets and liabilities of $3.2$3.5 million and non-cash expenses of $12.2$28.3 million which primarily related to stock-based compensation expense of $16.8$34.3 million, offsetreduced by $8.5 million from amortization and accretion of investment securities of $5.3 million.securities.

During the year ended December 31, 2023,2024, net cash used in operating activities of $73.5$93.9 million was primarily due to our net loss of $76.4$109.4 millionmillion, andoffset by changes in operating assets and liabilities of $3.0$3.2 million,million offset byand non-cash expenses of $5.9$12.2 million which primarily related to stock-based compensation expense of $5.5$16.8 million.million, reduced by $5.3 million from amortization and accretion of investment securities.

the costtiming and timingprogress of obtaining materials to produce adequate product supply for any preclinical orand clinical development of any product candidate we may developactivities;

our ability to establish new and maintain strategic collaborations,existing licensing or othercollaboration arrangements and the financial termsprogress of the development efforts of third parties with whom we may enter into such arrangements;

Until such time, if ever, as we can generate substantial revenue from product sales,revenue, we expect to finance our cash needs through a combination of equity offerings, debt financings, collaborations, strategic alliances, and marketing, distribution or licensing arrangements with third parties. However, we may be unable to raise additional funds or enter into such other arrangements when needed on favorable terms or at all. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of our existing stockholders may be materially diluted, and the terms of such securities could include liquidation or other preferences that adversely affect the rights of our common stockholders. Debt financing and preferred equity financing, if available, may involve agreements that include restrictive covenants that limit our ability to take specified actions, such as incurring additional debt, making capital expenditures or declaring dividends. If we raise funds through collaborations, strategic alliances or marketing, distribution or licensing arrangements with third parties, we may have to relinquish valuable rights to our technologies, future revenue streams, research programs or product candidates or grant licenses on terms that may not be favorable to us. If we are unable to raise additional funds through equity or debt financings or other arrangements when needed, we may be required to delay, reduce or eliminate our product development or future commercialization efforts, or grant rights to develop and market product candidates that we would otherwise prefer to develop and market ourselves.

Fair value of our common stock: Prior to the merger with Gemini closing, we determined the estimated fair value of our common-stock based on third-party valuations and certain other relevant objective and subjective factors. See Determination of the Fair Value of Common Stock below for additional details. After the close of the merger, the fair value of our common stock is determined based on the quoted market price of our common stock. See Determination of the Fair Value of Common Stock below for additional details.

Prior to the merger with Gemini closing, the estimated fair value of our common stock had been determined by our board of directors as of the date of each option grant with input from management, considering our most recently available third-party valuation of common stock, and our board of directors’ assessment of additional objective and subjective factors that we believed were relevant and which may have changed from the date of the most recent valuation through the date of the grant. These third-party valuations were performed in accordance with the guidance outlined in the American Institute of Certified Public Accountants’ Accounting and Valuation Guide, Valuation of Privately-Held-Company Equity Securities Issued as Compensation.

Upon closing of the merger, a public trading market for our common stock has been established and it is no longer necessary for our board of directors to estimate the fair value of our common stock in connection with our accounting for granted stock options and other such awards we may grant, as the fair value of our common stock is now determined based on the quoted market price of our common stock.stock

Our net losses were $63.5$123.0 million and $34.1$89.3 million for the threesix months ended MarchJune 31,30, 2026 and 2025, respectively. We had an accumulated deficit of $573.7$633.2 million as of MarchJune 31,30, 2026. Substantially all of our net losses have resulted from costs incurred in connection with our research and development programs and from selling, general and administrative costs associated with our operations. We expect our research and development expenses to continue to increase significantly in connection with the commencement and continuation of clinical trials of our product candidates. In addition, if we obtain regulatory approval for our product candidates, we will incur significant sales, marketing and manufacturing expenses. We also will continue to incur additional costs associated with operating as a public company and expect to continue to incur significant and increasing operating losses over the next several years and for the foreseeable future. Because of the numerous risks and uncertainties associated with developing pharmaceutical products, we are unable to predict the extent of any future losses or when we will become profitable, if at all. Even if we do become profitable, we may not be able to sustain or increase our profitability on a quarterly or annual basis.

successfully enroll subjects in and complete,complete our ongoing and planned clinical trials;

Until such time, if ever, we can generate substantial product revenue, we expect to finance our cash needs through a combination of private and public equity offerings, debt financings, collaborations, strategic alliances and licensing arrangements. Other than up to $80.0$50.0 million of additional advances that may be drawn at our option duringuntil 2026April 30, 2027 under the Hercules Loan Agreement, we do not have any committed external source of funds. The terms of any financing may adversely affect the holdings or the rights of our stockholders and the issuance of additional securities, whether equity or debt, by us, or the possibility of such issuance, may cause the market price of our shares to decline. To the extent that we raise additional capital through the sale of common stock or securities convertible or exchangeable into common stock, your ownership interest will be diluted, and the terms of those securities may include liquidation or other preferences that may materially adversely affect your rights as a common stockholder. Additional debt financing, if available, would increase our fixed payment obligations and may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, acquiring, selling or licensing intellectual property rights, and making capital expenditures, declaring dividends or other operating restrictions that could adversely impact our ability to conduct our business. We could also be required to meet certain milestones in connection with debt financing and the failure to achieve such milestones by certain dates may force us to relinquish rights to some of our technologies or product candidates or otherwise agree to terms unfavorable to us which could have a material adverse effect on our business, operating results and prospects.

Additionally, some of the clinical trials we conduct, such as our completed BEACON Phase 2 clinical trial of bitopertin, our ongoing RALLY-MF Phase 2 clinical trial of DISC-0974,selcodebart (DISC-0974), and our ongoing clinical trials of DISC-3405, may be open-label in study design and may be conducted at a limited number of clinical sites on a limited number of patients. An “open-label” clinical trial is one where both the patient and investigator know whether the patient is receiving the investigational product candidate or either an existing approved drug or placebo. Most typically, open-label clinical trials test only the investigational product candidate and sometimes may do so at different dose levels. Open-label clinical trials are subject to various limitations that may exaggerate any therapeutic effect as patients in open-label clinical trials are aware when they are receiving treatment. Open-label clinical trials may be subject to a “patient bias” where patients perceive their symptoms to have improved merely due to their awareness of receiving an experimental treatment. In addition, open-label clinical trials may be subject to an “investigator bias” where those assessing and reviewing the physiological outcomes of the clinical trials are aware of which patients have received treatment and may interpret the information of the treated group more favorably given this knowledge. The results from an open-label clinical trial may not be predictive of future clinical trial results when studied in a controlled environment with a placebo or active control.

From time to time, we may publicly disclose interim, top-line, initial or preliminary data from our clinical trials, which is based on a preliminary analysis of then-available data, and the results and related findings and conclusions are subject to change following a more comprehensive review of the data. For example, we announced initial data from our RALLY-MF Phase 2 DISC-0974selcodebart trial in patients with anemia of MF in December 2025.2025 and additional interim data from this trial in June 2026. We also may make assumptions, estimations, calculations and conclusions as part of our analyses of data, and may not have received or had the opportunity to fully and carefully evaluate all data. As a result, the interim, top-line, initial or preliminary results that we report may differ from future results of the same trials, or different conclusions or considerations may qualify such results, once additional data have been received and fully evaluated. Interim, top-line, initial and preliminary data from clinical trials are subject to the risk that one or more of the clinical outcomes may materially change as patient enrollment continues and more patient data become available. Interim, top-line, initial and preliminary data also remain subject to audit and verification procedures that may result in the final data being materially different from the interim, top-line, initial or preliminary data we previously published. As a result, interim, top-line, initial and preliminary data should be viewed with caution until the final data are available. Adverse differences between interim, top-line, initial or preliminary data and final data could significantly harm our business prospects and may cause the price of our common stock to fluctuate or decline.

Any results from early preclinical studies and clinical trials of bitopertin, DISC-0974,selcodebart, DISC-0998, DISC-3405 or our other product candidates or programs may not necessarily be predictive of the results from later preclinical studies and clinical trials. For example, we previously announced positive data from our Phase 2 BEACON and AURORA clinical trials of bitopertin in patients with EPP, but there can be no assurance that our Phase 3 APOLLO clinical trial of bitopertin in patients with EPP will be successful or that the results of our APOLLO clinical trial will support a traditional approval of bitopertin for EPP. In addition, we previously announced positive initial data from our RALLY-MF Phase 2 clinical trial of DISC-0974selcodebart in patients with anemia of MF. However, there can be no assurance that DISC-0974selcodebart will achieve the desired effects in this indication. Further, we announced positive results from a Phase 1 clinical trial of DISC-3405 in healthy adult volunteers in December 2024 and June 2025, which may not be indicative or predictive of future clinical trial results. Similarly, even if we are able to complete our planned preclinical studies and clinical trials of our product candidates according to our current development timeline, the results from such preclinical studies and clinical trials of our product candidates may not be replicated in subsequent preclinical studies or clinical trial results.

The incidence and prevalence for the target patient populations of our programs and product candidates have not been established with precision. Our lead heme biosynthesis modulation product candidate, bitopertin, is an oral, selective inhibitor of GlyT1. We are initially focused on developing bitopertin for the treatment of EPP and XLP, which are both diseases marked by severe photosensitivity and damage to the hepatobiliary system caused by the accumulation of PPIX. We are initially focused on developing DISC-0974selcodebart for anemia of MF and anemia of inflammatory bowel disease, or IBD. We are initially focused on developing DISC-3405 for the treatment of PV and sickle cell disease, or SCD. Our projections of both the number of people who have these diseases, as well as the subset of people with these diseases who have the potential to benefit from treatment with our programs and product candidates, are based on our estimates.

DISC-0974,Selcodebart, DISC-0998, and DISC-3405 are monoclonal antibodies. Manufacturing biologics, like monoclonal antibodies, especially in large quantities, is often complex and may require the use of innovative technologies to handle living cells. Each lot of an approved biologic must undergo thorough testing for identity, strength, quality, purity and potency. Manufacturing biologics requires facilities specifically designed for and validated for this purpose, and sophisticated quality assurance and quality control procedures are necessary. Slight deviations anywhere in the manufacturing process, including filling, labeling, packaging, storage and shipping and quality control and testing, may result in lot failures, product recalls or spoilage. When changes are made to the manufacturing process, we may be required to provide preclinical and clinical data showing the comparable identity, strength, quality, purity or potency of the products before and after such changes. If microbial, viral or other contaminations are discovered at the facilities of our manufacturers, such facilities may need to be closed for an extended period of time to investigate and remedy the contamination, which could delay clinical trials and adversely harm our business.

Our commercial success depends in part on our ability to obtain and maintain proprietary or intellectual property protection in the U.S. and other countries for our current or future product candidates, including our current lead product candidates, bitopertin, DISC-0974selcodebart and DISC-3405, and our other current or future programs, including DISC-0998, as well as for their respective compositions, formulations, methods used to manufacture them and methods of treatment, in addition to successfully defending these patents against third-party challenges. We seek to protect our proprietary and intellectual property position by, among other methods, filing patent applications in the U.S. and abroad related to our proprietary technology, inventions, and improvements that are important to the development and implementation of our business. Our ability to stop unauthorized third parties from making, using, selling, offering to sell, or importing our product candidates is dependent upon the extent to which we have rights under valid and enforceable patents or trade secrets that cover these activities. We also rely on trade secrets, know-how and continuing technological innovation to develop and maintain our proprietary and intellectual property position.

We have in-licensed, and may in the future in-license, a portion of our intellectual property, and, if we fail to comply with our obligations under these license arrangements, we could lose such intellectual property rights or owe damages to the licensor of such intellectual property. In particular, we have exclusively licensed intellectual property rights from Roche to develop and commercialize bitopertin, including certain back-up compounds and derivatives, for all prophylactic and therapeutic uses. The Roche license covers know-how, and certain specified Roche patent rights, including a composition of matter patent for bitopertin that expires in 2026. We also have exclusively licensed intellectual property rights from AbbVie Deutschland GmbH & Co. KG, or AbbVie, to develop and commercialize DISC-0974selcodebart and DISC-0998. The AbbVie license covers know-how, and certain specified AbbVie patent rights, including composition of matter and methods of use patents and patent applications for DISC-0974selcodebart and DISC-0998. We also have exclusively licensed intellectual property rights from Mabwell to develop and commercialize antibody products containing Mabwell’s MWTX-001, MWTX-002, and MWTX-003 antibodies. The Mabwell license covers know-how and certain specified Mabwell patent rights, including composition of matter and methods of use patents and patent applications for MWTX-001, MWTX-002 and MWTX-003.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has in recent years been the subject of much litigation. The degree of patent protection we require to successfully commercialize our current or future product candidates may be unavailable or severely limited in some cases and may not adequately protect our rights or permit us to gain or keep any competitive advantage. We cannot provide any assurances that any of our patents have, or that any of our pending patent applications that mature into issued patents will include, claims with a scope sufficient to protect bitopertin, DISC-0974,selcodebart, DISC-3405 or our other current or future product candidates. In addition, if the breadth or strength of protection provided by our patent applications or any patents we may own or in-license is threatened, we could dissuade companies from collaborating with us to license, develop or commercialize current or future product candidates.

Similarly, in the European Union, the European Commission, upon the recommendation of the EMA’s Committee for Orphan Medicinal Products, grants orphan designation in respect of products that are intended for the diagnosis, prevention or treatment of life-threatening or chronically debilitating conditions affecting no more than 5 in 10,000 persons in the European Union. Additionally, designation may be granted for products intended for the diagnosis, prevention, or treatment of a life-threatening, seriously debilitating or serious and chronic condition when, without incentives, it is unlikely that sales of the product in the European Union would generate sufficient return to justify the necessary investment in developing the product. In each case, there must be no satisfactory method of diagnosis, prevention, or treatment of the applicable condition which is authorized for marketing in the European Union (or, if such a method exists, the applicable product would be of significant benefit to those affected by the condition). In the European Union, orphan designation entitles a party to financial incentives such as reduction of fees or fee waivers. The European CommitteeCommission forhas Orphangranted Medicalorphan Products adopted a positive opinion on Orphan Designationdesignation for bitopertin for treatment of EPP.EPP and for selcodebart for treatment of myelofibrosis.

We were granted fast track designation by the FDA for DISC-3405 for the treatment of PV in September 2023 and for DISC-0974selcodebart for the treatment of anemia in non-dialysis dependent chronic kidney disease in February 2024, and we may seek fast track designation for certain of our product candidates. If a drug or biologic is intended for the treatment of a serious or life-threatening condition and the drug or biologic demonstrates the potential to address unmet medical needs for this condition, the sponsor may apply for fast track designation. The FDA has broad discretion whether or not to grant this designation, so even if we believe a particular product candidate is eligible for this designation, the FDA may disagree and instead decide not to grant it. Even if we do receive fast track designation, we may not experience a faster development process, review or approval compared to conventional FDA procedures. The FDA may withdraw fast track designation if it believes that the designation no longer meets the conditions for such designation. Fast track designation alone does not guarantee qualification for the FDA’s priority review procedures.

We may also be subject to state and foreign equivalents of each of the healthcare laws and regulations described above, among others, some of which may be broader in scope and may apply regardless of the payor. Many U.S. states have adopted laws similar to the federal Anti-Kickback Statute and False Claims Act, and may apply to our business practices, including, but not limited to, research, distribution, sales or marketing arrangements and claims involving healthcare items or services reimbursed by non-governmental payors, including private insurers. In addition, some states have passed laws that require pharmaceutical companies to comply with the April 2003 Office of Inspector General Compliance Program Guidance for Pharmaceutical Manufacturers and/or the Pharmaceutical Research and Manufacturers of America’s Code on Interactions with Healthcare Professionals. Several states also impose other marketing restrictions or require pharmaceutical companies to make marketing or price disclosures to the state and require the registration of pharmaceutical sales representatives. State and foreign laws, including for example the European Union General Data Protection Regulation, also govern the privacy and security of health information in some circumstances,information, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts. ThereAny arefailure ambiguitiesor asperceived to what is required to comply with these state requirements and if we failfailure to comply with an applicable state lawlegal requirement we could beresult subjectin to penalties. Finally, there are statepenalties and foreignreputational laws governing the privacy and security of health information, many of which differ from each other in significant ways and often are not preempted by HIPAA, thus complicating compliance efforts.harm.

The regulatory framework for the collection, use, safeguarding, sharing, transfer and other processing of personal information worldwide is rapidly evolving and is likely to remain uncertain for the foreseeable future. We possess and process sensitive information, including patient health information. In the U.S., there are numerous federal and state privacy and data security laws and regulations governing the collection, use, disclosure and protection of personal information, including health information privacy laws, security breach notification laws and consumer protection laws. These federal and state laws, in many cases, are not preempted by HIPAA and may be subject to varying interpretations by the courts and government agencies. These varying interpretations can create complex compliance issues for us and our partners and potentially expose us to additional expense, adverse publicity and liability, any of which could adversely affect our business. There is ongoing concern from privacy advocates, regulators and others regarding data privacy and security issues, and the number of jurisdictions with data privacy and security laws has been increasing. Also, there are ongoing public policy discussions regarding whether the standards for de-identification, anonymization or pseudonymization of health information are sufficient, and the risk of re-identification sufficiently small, to adequately protect patient privacy. We expect that there will continue to be new proposed and amended laws, regulations and industry standards concerning privacy, data protection and information security in the United States. For example, California enacted the California Consumer Privacy Act, or CCPA, as amended by the California Privacy Rights Act, is a comprehensive privacy law that broadly defines personal information, gives California residents expanded rights to access and delete their personal information, and places stringent privacy and security obligations on businesses covered by the law, including obligations to provide detailed disclosures to California consumers about their data collection, use and sharing practices, and to provide such consumers with ways to opt out of certain sales or transfers of personal information. ItA state agency was created to regulate the implementation and enforcement of the CCPA which may increase the risk of regulatory fines and penalties. The CCPA also provides for civil penalties for violations,penalties, and allows for a private right of action for certain types of data breachesbreaches, thatwhich ismay expectedlead to increaseincreased data breach litigation.litigation In addition, the CCPA was amended by the California Privacy Rights Act, which significantly modified the CCPA by expanding consumer rights with respect to certain sensitive information, and creating a new state agency that is vested with authority to implement and enforce the CCPA.risk.

Comprehensive laws similar to the CCPA have been passed in numerous other states outside of California. These laws are substantially similar in scope and contain many of the same requirements and exceptions as the CCPA, including a general exemption for clinical trial data and limited obligations for entities regulated by HIPAA. However, we cannot yet determine the full impact these laws or other such future laws, regulations and standards may have on our current or future business. Any of these laws may broaden their scope in the future, and similar laws have been proposed on both a federal level and instate more than half of the states in the U.S.levels. Such proposed legislation, if enacted, may add additional complexity, variation in requirements, restrictions and potential legal risk, require additional investment of resources in compliance programs, impact strategies and the availability of previously useful data and could result in increased compliance costs and/or changes in our business practices and policies.

In addition to comprehensive consumer privacy laws, certain states have enacted privacy laws with more limited focus. For example, the state of Washington has passed athe law“My Health My Data Act” to protect medical and health information not subject to HIPAA. This law has a private right of action, which further increases the relevant compliance risk. Connecticut and Nevada have also passed similar laws regulating consumer health data. In addition, otherOther states have proposed and/or passed legislation that regulates the privacy and/or security of certain specific types of information. For example, a small number of states have passed laws that regulate biometric information. The existence of comprehensive privacy laws in different states in the country would make our compliance obligations more complex and costly and may increase the likelihood that we may be subject to enforcement actions or otherwise incur liability for noncompliance. These various privacy and security laws may impact our business activities, including our identification of research subjects, relationships with business partners and ultimately the marketing and distribution of our products. State laws are changing rapidly and there have been proposals for a new comprehensive federal data privacy law to which we may likely become subject, if enacted.

The collection, use, storage, disclosure, transfer or other processing of personal data regarding individuals in the EEA and UK, including personal health data, is subject to the EU General Data Protection Regulation 2016/679, or EU GDPR, with respect to individuals in the EEA and the UK General Data Protection Regulation (following the incorporation of the EU GDPR into UK law), or UK GDPR, with respect to individuals in the UK, and together with the EU GDPR, GDPR. The GDPR is wide-ranging in scope and imposes numerous requirements on companies that process personal data, including requirements relating to having a legal basis or condition for processing personal data, stricter requirements relating to processing sensitive data (such asincluding health data), where required by GDPR obtaining consent of the individuals to whom the personal data relates, providing information to individuals regarding data processing activities, implementing safeguards to protect the security and confidentiality of personal data, providing notification of data breaches, requiring data protection impact assessments for high risk processing and taking certain measures when engaging third-party processors. The GDPR permits data protection authorities to impose large penalties for violations of the GDPR, including potential fines of up to €20 million (£17.5 million for the UK) or 4% of annual global revenues, whichever is greater. The GDPR also confers a private right of action on data subjects and consumer associations to lodge complaints with supervisory authorities, seek judicial remedies, and obtain compensation for damages resulting from violations of the GDPR. The GDPR increased our responsibility and liability in relation to personal data that we process where such processing is subject to the GDPR, and we may be required to put in place additional mechanisms to ensure compliance with the GDPR, including as implemented by individual countries. Compliance with the GDPR is a rigorous and time-intensive process that may increase our cost of doing business or require us to change our business practices, and despite those efforts, there is a risk that we may be subject to fines and penalties, litigation, and reputational harm in connection with our European activities.

Although the UK is regarded as a third country under the EU GDPR, the European Commission has issued an “Adequacy Decision” recognizing the UK as providing adequate protection under the EU GDPR and, therefore, transfers of personal data subject to the EU GDPR to the UK remain unrestricted. The UK government has confirmed that personal data transfers from the UK to the EEA remain free flowing. The UK Government introduced the Data Protection and Digital Information Bill, which failed in the UK legislative process.

We may use and integrate artificial intelligence, or AI, into our business processes, and this innovation presents risks and challenges that could affect its adoption, and therefore our business. If we enable or offer solutions that draw controversy due to perceived or actual negative societal impact, we may experience brand or reputational harm, competitive harm or legal liability. The use of certain AI technology can give rise to cybersecurity and intellectual property risks, including compromises to personal or other confidential information, proprietary intellectual property and intellectual property infringement. To the extent we develop our own AI systems, then the risk of intellectual property infringement could arise from third party data sources being used to train our AI models, and from the output of AI systems reproducing or incorporating third party intellectual property rights, in each case without the right to do so. Further, a risk of our proprietary intellectual property rights being compromised through the use of AI could arise through third party vendors using our data to train their models and/or to generate output for other users of their systems. If our third party vendors use our data (which includes personal data) to train their AI models and/or to generate output for other users of their systems, this could also give rise to regulatory risks. Additionally, we expect to see increasing government and supranational regulation related to AI use and ethics, which may also significantly increase the burden and cost of research, development and compliance in this area. For example, the European Union’s Artificial Intelligence Act, or the AI Act, the world’s first comprehensive AI law, enteredis into forcecurrently in August 2024 and,effect with somerespect exceptions,to becamemost effectiveof inits August 2025.provisions. As currently enacted, the AI Act, which may be amended as part of the EU’s Digital Omnibus, imposes significant obligations on providers and deployers of high risk AI systems, and encourages providers and deployers of AI systems to account for European Union ethical principles in their development and use of these systems. If we develop or use AI systems that are governed by the AI Act, it may necessitate ensuring higher standards of data quality, transparency, and human oversight, as well as adhering to specific and potentially burdensome and costly ethical, accountability, and administrative requirements.

We rely on information technology systems and infrastructure that we or our third-party providers operate to process, transmit and store electronic information in our day-to-day operations. In connection with our product discovery efforts, we may collect and use a variety of personal data and other confidential and/or proprietary data, such as names, mailing addresses, email addresses, phone numbers and clinical trial information. A successful cyberattack could result in the theft, destruction or misuse of intellectual property, data, or other misappropriation of assets, or otherwise compromise our confidential or proprietary information and disrupt our operations. Cyberattacks generally are increasing in their frequency, sophistication and intensity, including in relation to the proliferation of artificial intelligence-enabled systems, and have become increasingly difficult to detect. Cyberattacks could include wrongful conduct by hostile foreign governments, insiders such as employees, contractors or other third-parties and industrial espionage, wire fraud and other forms of cyber fraud, the deployment of harmful malware, ransomware, denial-of-service, social engineering fraud (including phishing attacks) or other means to threaten or compromise the security, confidentiality, integrity and availability of systems and information. A successful cyberattack could cause serious negative consequences for us, including, without limitation, the disruption of operations, the misappropriation of protected information or confidential business information, including personal data, financial information, trade secrets, financial loss and the disclosure of corporate strategic plans.

We rely on our third-party providers to implement effective security measures and identify and correct for any such failures, deficiencies, vulnerabilities, compromises, cybersecurity incidents or data breaches. We also rely on our employees and consultants to safeguard their security credentials and follow our policies and procedures regarding use and access of computers and other devices that may contain protected information and our sensitive information. If we or our third-party providers fail to maintain or protect our information technology systems, infrastructure and data integrity effectively or fail to anticipate, plan for or manage significant disruptions to our information technology systems and infrastructure, we or our third-party providers could have difficulty preventing, detecting and controlling such cyber-attacks, and any such attacks could result in the losses described above as well as disputes with physicians, patients and our partners, regulatory sanctions or penalties, increases in operating expenses, expenses or lost revenue or other adverse consequences, any of which could have a material adverse effect on our business, results of operations, financial condition, prospects and cash flows. Any failure by such third parties to prevent or adequately mitigate cybersecurity incidents, data breaches, compromises or other improper access to or disclosure of such information could have similarly adverse consequences for us. If we are unable to prevent or adequately mitigate the impact of such cybersecurity incidents, compromises or data breaches, we could be exposed to litigation and governmental investigations, inquiries, orders, penalties or fines, which could lead to a potential disruption to our business and financial penalties or losses. By way of example, the CCPA, which was modified by the CPRA,CCPA creates individual privacy rights for California consumers and increases the privacy and security obligations of entities handling certain personal data. The CCPA provides for civil penalties of up to $7,500 per violation, as well as a private right of action for certain types of data breaches that has, and is expected to continue to, increase the volume of data breach related litigation filed in California. Our contracts may not contain limitations of liability,liability for data breaches we experience, and even where they do, there can be no assurance that limitationssuch of liability in our contractslimits are sufficient to protect us from liabilities,material damages,damages or claims related to our privacy and data security obligations. Further, although we maintain cyber liability insurance, this insurance may not provide adequate coverage against potential liabilities related to any experienced cybersecurity incidentincidents or data breach.breaches we may experience.

As of MarchJune 31,30, 2026, we had 154165 full-time employees and no part-time employees. We expect to experience significant growth in the number of our employees and the scope of our operations, particularly as we mature as a public company and in the areas of product development, regulatory affairs and, in anticipation of the potential regulatory approval of bitopertin, sales, marketing and distribution. To manage our anticipated future growth, we must continue to implement and improve our managerial, operational and financial systems, expand our facilities and continue to recruit and train additional qualified personnel. Due to our limited financial resources, we may not be able to effectively manage the expansion of our operations or recruit and train additional qualified personnel. The expansion of our operations may lead to significant costs and may divert our management and business development resources. Any inability to manage growth could delay the execution of our business plans or disrupt our operations.

If our existing securityholders sell, or indicate an intention to sell, substantial amounts of our common stock in the public market, the trading price of our common stock could decline. As of MarchJune 31,30, 2026, we had 38,190,46438,345,666 shares of common stock outstanding. All outstanding shares of common stock, other than shares held by our affiliates are freely tradable, without restriction, in the public market. In addition, shares of common stock that are subject to outstanding options of ours are or will become eligible for sale in the public market to the extent permitted by the provisions of various vesting agreements and Rules 144 and 701 under the Securities Act. If these shares are sold, the trading price of our common stock could decline.

As of MarchJune 31,30, 2026, our executive officers, directors and principal stockholders, in the aggregate, beneficially owned approximately 31% of our outstanding shares of common stock. As a result, if these stockholders were to choose to act together, they would be able to significantly influence all matters submitted to our stockholders for approval, as well as our management and affairs. For example, these persons, if they choose to act together, would significantly influence the election of directors and approval of any merger, consolidation or sale of all or substantially all of our assets. This concentration of voting power could delay or prevent an acquisition of us on terms that other stockholders may desire.

We are a clinical-stage biopharmaceutical company focused on the discovery, development, and commercialization of novel treatments for patients suffering from serious hematologic diseases. We have assembled a portfolio of clinical and preclinical product candidates that aim to modify fundamental biological pathways associated with the formation and function of red blood cells, specifically heme biosynthesis and iron homeostasis. Our current pipeline includes bitopertin for the treatment of erythropoietic porphyrias, or EPs, including erythropoietic protoporphyria, or EPP, and X-linked protoporphyria, or XLP; selcodebart (DISC-0974) for the treatment of anemia of myelofibrosis, or MF, and anemia of inflammatory bowel disease, or IBD; and DISC-3405 for the treatment of polycythemia vera, or PV, sickle cell disease, or SCD, and other hematologic disorders. In addition, our preclinical programs include DISC-0998 for the treatment of anemia associated with inflammatory diseases. Our approach to product candidate development leverages well-understood molecular mechanisms that have been validated in humans. We believe that each of our product candidates, if approved, has the potential to improve the lives of patients suffering from hematologic diseases.

We have completed two Phase 2 clinical trials of bitopertin: BEACON, an open-label, parallel-dose clinical trial in EPP and XLP patients conducted at sites in Australia, and AURORA, a randomized, double-blind, placebo-controlled clinical trial in EPP patients conducted at sites in the United States. In both trials, bitopertin significantly reduced the toxic metabolite, protoporphyrin IX, or PPIX, and was associated with improvements in measures of time spent in sunlight and quality of life. In addition, bitopertin was generally well-tolerated. All participants in AURORA and BEACON were eligible to participate in HELIOS, an ongoing open-label, long-term extension study of bitopertin in EPP and XLP patients. Interim data from HELIOS, presented in June 2025,2025 and June 2026, demonstrated that longer term treatment of bitopertin was associated with sustained reductions in PPIX, as well as improvements in quality of life and liver biomarkers. InBitopertin ouris end-of-Phasealso 2currently meetingbeing studied in September 2024, the U.S. Food & Drug Administration, or the FDA, agreed with the potential for reduction of PPIX to serve as a surrogate endpoint to support a potential accelerated approval of bitopertin in EPP and XLP. In our Type C meeting in December 2024, we aligned with the FDA on the design of APOLLO, a Phase 3, randomized, double-blind, placebo-controlled, clinical trial of bitopertin in EPP and XLP patients that in the setting of an accelerated approval would serve as a post-marketing confirmatory trial. Wewe initiated the APOLLO trial in May 20252025. and inIn September 2025 we submitted a New Drug Application, or NDA, for accelerated approval of bitopertin in EPP and XLP in the United States based on our existingPhase 2 data. In October 2025, we were awarded a Commissioner’s National Priority Voucher, or CNPV, from the FDA for bitopertin in EPP and XLP. The CNPV program, announced in June 2025, is designed to accelerate the development and review of certain drugs aligned with US national health priorities. The FDA accepted our NDA for review in November 2025 and in February 2026 issued a complete response letter, or CRL. Although the FDA agreed that clinical data from AURORA and BEACON provided sufficient evidence that bitopertin significantly lowers whole blood metal-free PPIX, theThe FDA concluded that the AURORA and BEACON trials did not show evidence of association between percent change in PPIX and sunlight exposure-based endpoints as measured in the trials.trials, Asresulting such, the FDA determined that there isin uncertainty regarding whether bitopertin’s effect on PPIX is reasonably likely to predict clinical benefit, despite the strong mechanistic and biological plausibility supporting the use of the PPIX biomarker in protoporphyria. TheIn our Type A meeting during the second quarter of 2026, the FDA indicated that results of the ongoing Phase 3 APOLLO trialtrial, if successful, could serve as evidencethe basis for a response to the CRL and could potentially support a potential traditional approval, and we have scheduled a Type A meeting with the FDA during the second quarter of 2026 to review our approach for potentially resubmitting our NDA.approval. We completed enrollment in APOLLO (n=183) in the first quarter of 2026 and expect to report topline data in the fourth quarter of 2026,2026. followingIf whichsuccessful, we plan to submit a response to the CRL and would then anticipate an FDA decision on our NDA by mid-2027.

Iron Homeostasis: Selcodebart (DISC-0974) and DISC-3405

DISC-0974Selcodebart is the lead product candidate in our iron homeostasis portfolio and was licensed from AbbVie Deutschland GmbH & Co. KG, or AbbVie. DISC-0974Selcodebart is designed to suppress hepcidin production and increase serum iron levels. We completed a Phase 1 clinical trial in healthy volunteers in the United States in June 2022, with results showing an acceptable tolerability profile and evidence of target engagement, iron mobilization and augmented erythropoiesis. We initiated a Phase 1b/2 clinical trial in June 2022 in patients with anemia of MF, with results from the Phase 1b portion of this clinical trial showing substantial and sustained reductions in hepcidin levels and increases in iron alongside strong hematologic responses across patient types and an acceptable tolerability profile. We initiated RALLY-MF, the open-label Phase 2 portion of this clinical trial, in December 2024 and reported initial data in December 2025,2025 and interim data in June 2026, with results demonstrating meaningful overall anemia responses across all patient subgroups, regardless of baseline transfusion status and independent of concomitant Janus Kinase, or JAK, inhibitor therapy use. We expect to share updated data from this trial in June 2026 and toplineadditional data in the fourth quarter of 2026. If positive, we expect to hold an end-of-Phase 2 meeting with the FDA for DISC-0974selcodebart in anemia of MF by the end of 2026. We also initiated RALLY-IBD, a Phase 2 clinical trial of DISC-0974selcodebart in patients with IBD and anemia in the first quarter of 2026, with initial data anticipated in 2027, and we are planning exploratory studies in additional patient populations with anemia of chronic disease. We are also developing a preclinical anti-hemojuvelin, or HJV, monoclonal antibody, DISC-0998, which also targets hepcidin suppression and was licensed from AbbVie. DISC-0998 is designed to increase serum iron levels and has an extended serum half-life as compared to DISC-0974.selcodebart. We believe this profile may be desirable in certain subsets of patients with anemia associated with inflammatory diseases.

In addition, we are developing DISC-3405, a monoclonal antibody against Transmembrane Serine Protease 6, or TMPRSS6, that we licensed from Mabwell Therapeutics, Inc., or Mabwell. DISC-3405 is part of our iron homeostasis portfolio and is designed to induce hepcidin production and reduce serum iron levels. We initiated a Phase 1 clinical trial of DISC-3405 in healthy adult volunteers in October 2023 and presented interim data from the single-ascending dose, or SAD, portion of this clinical trial in June 2024. We presented data from the multiple ascending dose, or MAD, portion of this clinical trial in December 2024, and presented updated data from both the SAD and MAD portions of this clinical trial in June 2025, with results showing an acceptable tolerability profile and evidence of target engagement, including dose-related increases in serum hepcidin and corresponding reductions in serum iron across all dose levels. We are developing DISC-3405 for the treatment of PV, SCD, and other hematologic disorders. We initiated RESTORE-PV, an open-label Phase 2 clinical trial of DISC-3405 in patients with PV, in the first half ofJune 2025, with initial data expected in the fourththird quarter of 2026. We also initiated a Phase 1b, open-label clinical trial of DISC-3405 in patients with SCD in October 2025, with initial data expected in the fourth quarter of 2026, and plan to explore the role of therapeutic iron restriction in other indications.

As of MarchJune 31,30, 2026, we had cash, cash equivalents and marketable securities of $730.2$717.7 million. We believe that our cash, cash equivalents and marketable securities will be sufficient to fund our current operating and capital expenditure plans and our debt service obligations into 2029, without taking into account any potential net cash inflows from bitopertin or any other marketed product, if approved during such period. We have based these estimates on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. See "Liquidity and Capital Resources" for additional details.

Comparison of the Three and Six Months Ended MarchJune 31,30, 2026 and 2025

The following table summarizes our results of operations for the three and six months ended MarchJune 31,30, 2026 and 2025 (in thousands):

The following table summarizes our research and development expenses for the three and six months ended MarchJune 31,30, 2026 and 2025 (in thousands):

Research and development expenses were $45.9$46.9 million for the three months ended MarchJune 31,30, 2026, compared to $27.8$46.3 million for the three months ended MarchJune 31,30, 2025. The increase of $18.1$0.6 million was primarily due to an increase of $7.5 million in DISC-3405 development expenses. This increase was primarily driven by aincreases $5.0of $7.7 million milestoneand payment$3.1 triggeredmillion by the first administrationrelated to aselcodebart patient(DISC-0974) inand theDISC-3405, Phaserespectively, 1bprimarily related to clinical trial ofadvancement DISC-3405and indrug amanufacturing second indication.activities. Personnel-related costs increased $7.1$5.9 million related to increasedhigher research and development headcount, including an increase of $2.8$3.1 million in stock-based compensation driven by awards granted under our equity compensation plansplans. andThese anincreases increasewere partially offset by a decrease of $0.2$15.0 million related to an organizational restructuring. DISC-0974 development expenses increased $2.0 million primarily due to clinical trial advancement and drug manufacturing activities. There was also a $0.9 million increase in bitopertin development expenseexpenses reflectingprimarily ongoingdriven by a $10.0 million milestone payment and higher manufacturing costs associatedincurred with bothduring the APOLLOcomparative trial and the HELIOS long-term extension trial.period. Other research programs and expenses increasedalso $0.6decreased million$1.1 related to expanded research initiatives and ongoing program support.million.

The following table summarizes our selling, general and administrative expenses for the three and six months ended MarchJune 31,30, 2026 and 2025 (in thousands):

Selling, general and administrative expenses were $23.6$18.1 million for the three months ended MarchJune 31,30, 2026, compared to $12.2$15.1 million for the three months ended MarchJune 31,30, 2025. The increase of $11.4$3.1 million was primarily due to an increase of $8.7$3.9 million in personnel-related costs due to increased selling, general and administrative headcount, including an increase of $2.8$2.4 million in stock-based compensation driven by awards granted under our equity compensation plansplans. and anThis increase ofwas $1.6partially offset by a $1.2 million related to an organizational restructuring. There was also a $2.1 million increasedecrease in legal, consulting, and professional fees primarily related to developingchanges ourin the timing and scope of commercialization capabilities.activities.

Other income (expense), net was $6.1$5.6 million and $11.7 million for the three and six months ended MarchJune 31,30, 2026, respectively, compared to $6.0$6.2 million and $12.2 million for the three and six months ended MarchJune 31,30, 2025.2025, respectively. Other income (expense), net consists primarily of interest income from our cash, cash equivalents and marketable securities, partially offset by interest expense associated with our term loan.

Income tax expense was $0.1 million for both the three and six months ended MarchJune 31,30, 20262026, compared to $0.1 million and $0.2 million for the three and six months ended June 30, 2025, respectively. This expense primarily relates to state income tax resulting from an increase in interest income.

To date, we have funded our operations primarily with proceeds from the sale of our convertible preferred stock and common stock, the proceeds from the merger with Gemini, proceeds from various private and public sales of our equity securities and proceeds from borrowings under the Hercules Loan Agreement. Through MarchJune 31,30, 2026, we have received net proceeds of $144.5 million from sales of our Series Seed, Series A and Series B convertible preferred stock, $89.5 million from the merger with Gemini, $941.8 million from various private and public sales of our equity securities, and $27.6$57.6 million from net borrowings under the Hercules Loan Agreement. As of MarchJune 31,30, 2026, we had cash, cash equivalents and marketable securities of $730.2$717.7 million.

We have incurred significant operating losses since inception and, as of MarchJune 31,30, 2026, had an accumulated deficit of $573.7$633.2 million. In addition, we expect to continue to incur significant and increasing expenses and operating losses for the foreseeable future. We believe that our cash, cash equivalents and marketable securities will be sufficient to fund our current operating and capital expenditure plans and our debt service obligations into 2029, without taking into account any potential net cash inflows from bitopertin or any other marketed product, if approved during such period. We have based these estimates on assumptions that may prove to be wrong, and we could exhaust our available capital resources sooner than we expect. We may also pursue additional cash resources through public or private equity offerings, collaborations or additional debt financing.

During the threesix months ended MarchJune 31,30, 2026, net cash used in operating activities of $62.2$106.4 million was primarily due to our net loss of $63.5$123.0 million and the change in operating assets and liabilities of $10.0$8.6 million. These were partially offset by non-cash expenses of $11.3$25.2 million which included $11.9$25.9 million in stock-based compensation, reduced by $1.1$1.6 million from amortization and accretion of investment securities.

During the threesix months ended MarchJune 31,30, 2025, net cash used in operating activities of $41.4$89.3 million was primarily due to our net loss of $34.1$89.3 million and the change in operating assets and liabilities of $11.5$11.2 million. These were partially offset by non-cash expenses of $4.2$11.2 million which included $6.4$14.8 million in stock-based compensation, reduced by $2.5$5.1 million from amortization and accretion of investment securities.

During the threesix months ended MarchJune 31,30, 2026, net cash provided by investing activities was primarily due to maturities of marketable securities of $152.1$266.4 million, partially offset by purchases of marketable securities of $93.8$186.5 million.

During the threesix months ended MarchJune 31,30, 2025, net cash used in investing activities was primarily due to purchases of marketable securities of $347.3$405.9 million, partially offset by maturities of marketable securities of $75.5$185.8 million.

During the threesix months ended MarchJune 31,30, 2026, net cash provided by financing activities of $1.7$34.0 million consisted primarily of net proceeds from the issuance of long-term debt of $30.0 million and proceeds from stock option exercises.

During the threesix months ended MarchJune 31,30, 2025, net cash provided by financing activities of $244.3$245.1 million consisted primarily of aggregate net proceeds of $243.4 million from our underwritten offering in January 2025.

The following table summarizes our contractual obligations as of MarchJune 31,30, 2026 and the effects that such obligations are expected to have on our liquidity and cash flows in future periods (in thousands):

(1) Amounts reflect contractual rent payments due for our leased and subleased office spaces in Watertown, Massachusetts as of MarchJune 31,30, 2026 and include contractual payments due under our forward-starting lease which is expected to commence in December 2026. The term date for our existing lease is December 31, 2029 and the term date for our existing sublease is November 30, 2026.