Protoporphyria, Erythropoietic, X-Linked Dominant

Top-line results from AURORA, the placebo-controlled phase 2 study of bitopertin in erythropoietic porphyrias (EPP), expected March / April 2024On track to deliver multiple read-outs in 2024, including updated results from phase 1b/2 study of DISC-0974 in anemia of myelofibrosis (MF) 1H’24Strengthened leadership team with the appointments of Jean Franchi as Chief Financial Officer and Pamela Stephenson as Chief Commercial Officer, and the promotion of Jonathan Yu to Chief Operating OfficerWell-capitalized, ending 2023 with approximately $360M in cash and cash equivalents, which provides runway well into 2026 WATERTOWN, Mass., March 21, 2024 (GLOBE NEWSWIRE) -- Disc Medicine, Inc. (NASDAQ:IRON), a clinical-stage biopharmaceutical company focused on the discovery, development, and commercialization of novel treatments for patients suffering from serious hematologic diseases, today reported financial results for the fourth quarter and full year ended December 31, 2023, and provided an update on recent program and corporate developments. “The past year has been truly remarkable for Disc and marks another important chapter in our company’s story. During 2023, we provided the first evidence of the therapeutic potential of our programs, with positive read-outs in patients for both bitopertin and DISC-0974. In addition, we advanced a third program, DISC-3405, into the clinic and fortified our balance sheet, so we can execute our strategy with confidence,” said John Quisel, J.D., Ph.D., President and Chief Executive Officer of Disc. “These achievements have positioned us well for 2024, which promises to be another transformational year, and I want to express my deep gratitude to our team for their determination and hard work. We’re looking forward to sharing AURORA data in the coming weeks, as well as updated data for DISC-0974 in MF and initial data for DISC-3405 in healthy volunteers in the first half of this year.” Recent Business Highlights and Upcoming Milestones: Bitopertin: GlyT1 Inhibitor (Heme Synthesis Modulator) Completed enrollment of its phase 2 program of bitopertin in erythropoietic porphyrias: BEACON, an open-label phase 2 clinical study of bitopertin in patients with EPP and X-linked protoporphyria (XLP), which was expanded to include adolescentsAURORA a phase 2 randomized, placebo-controlled clinical study of bitopertin in adults with EPP Presented positive results from the phase 2 BEACON trial at ASH 2023, showing: Significant, sustained reductions in whole blood protoporphyrin IX (PPIX) levels >40%Robust and consistent improvements across all measures of sunlight tolerance, including >3x improvement over historical control of precedented pivotal endpointBitopertin was generally well-tolerated with stable hemoglobin at both dose levels Topline AURORA data planned for press release and corporate presentation in March/April 2024 DISC-0974: Anti-Hemojuvelin Antibody (Hepcidin Suppression) Presented positive, initial data from ongoing phase 1b/2 clinical study in MF patients with severe anemia at ASH 2023: Treatment at initial dose levels (14 mg, 28 mg, 50 mg) resulted in substantial, dose-dependent decreases in hepcidin and increases in serum ironHematologic activity was observed in MF patients, regardless of concomitant JAK inhibitor use. Four of seven (57%) evaluable non-transfusion-dependent (NTD) patients reached a >1.5g/dL hemoglobin increase and one of two transfusion-dependent (TD) patients achieved transfusion independence.DISC-0974 was generally well-toleratedEnrollment and dose escalation is ongoing Presented initial data from the 28 mg cohort of the ongoing phase 1b/2 clinical study of patients with anemia of chronic kidney disease who are not receiving dialysis (NDD-CKD) Data demonstrated meaningful reductions in serum hepcidin and corresponding increases in serum iron with a similar PK/PD profile as seen in Disc’s healthy volunteer studyEnrollment and dose escalation is ongoing Updated phase 1b/2 data from DISC-0974 in anemia in MF patients is expected to be presented in the first half of 2024Updated phase 1b/2 data from DISC-0974 in anemia in NDD-CKD is expected to be shared in the second half of 2024Received FDA fast track designation in February 2024 for DISC-0974 for the treatment of anemia in NDD-CKD DISC-3405: Anti-TMPRSS6 Antibody (Hepcidin Induction) Initiated a phase 1 SAD / MAD study in healthy volunteers in October 2023Initial SAD data expected to be presented in the first half of 2024Received FDA orphan drug designation in February 2024 for DISC-3405 for the treatment of PV Corporate: As the company enters late-stage development and begins planning for commercialization, Disc expanded its leadership team with the appointments of industry veterans Jean Franchi as Chief Financial Officer and Pamela Stephenson as Chief Commercial Officer, and the promotion of Jonathan Yu to Chief Operating Officer Full Year 2023 Financial Results: Cash Position: Cash and cash equivalents were $360.4 million as of December 31, 2023, which are expected to fund our operational plans well into 2026, compared to $194.6 million as of December 31, 2022. The increase was primarily due to the completion of a registered direct offering in February 2023 and a publicly marketed follow-on offering in June 2023.Research and Development Expenses: R&D expenses were $69.3 million for the full year ended December 31, 2023, as compared to $33.4 million for the full year ended December 31, 2022. The increase in R&D expenses were primarily driven by the progression of Disc’s portfolio, including bitopertin’s ongoing two phase 2 clinical studies and drug manufacturing, phase 1 study initiation for DISC-3405, and increased headcount.General and Administrative Expenses: G&A expenses were $21.9 million for the full year ended December 31, 2023, as compared to $14.0 million for the full year ended December 31, 2022. The increase in G&A expenses was primarily due to increased headcount and increased costs as a public company.Net Loss: Net loss was $76.4 million for the full year ended December 31, 2023, as compared to $46.8 million for the full year ended December 31, 2022. The increase was primarily due to higher operating costs in the current period to support the continued advancement of our pipeline. About Disc Medicine Disc Medicine (NASDAQ:IRON) is a clinical-stage biopharmaceutical company committed to discovering, developing, and commercializing novel treatments for patients who suffer from serious hematologic diseases. We are building a portfolio of innovative, potentially first-in-class therapeutic candidates that aim to address a wide spectrum of hematologic diseases by targeting fundamental biological pathways of red blood cell biology, specifically heme biosynthesis and iron homeostasis. For more information, please visit www.discmedicine.com. Available Information Disc announces material information to the public about the Company, its products and services, and other matters through a variety of means, including filings with the U.S. Securities and Exchange Commission (SEC), press releases, public conference calls, webcasts and the investor relations section of the Company website at ir.discmedicine.com in order to achieve broad, non-exclusionary distribution of information to the public and for complying with its disclosure obligations under Regulation FD. Disc Cautionary Statement Regarding Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including, but not limited to, express or implied statements regarding Disc’s expectations with respect to its AURORA phase 2 and BEACON phase 2 clinical studies of bitopertin and the results thereof, and its phase 1b/2 study of bitopertin in Diamond-Blackfan Anemia, its phase 1b/2 clinical studies of DISC-0974 in patients with MF and NDD-CKD patients with anemia, its phase 1 clinical study of DISC-3405 in healthy volunteers; projected timelines for the initiation and completion of its clinical trials, anticipated timing of release of data, and other clinical activities; Disc’s business plans, objectives and expected contributions of management; and Disc’s beliefs about operating expenses and that it will have capital to fund Disc well into 2026. The use of words such as, but not limited to, “believe,” “expect,” “estimate,” “project,” “intend,” “future,” “potential,” “continue,” “may,” “might,” “plan,” “will,” “should,” “seek,” “anticipate,” or “could” or the negative of these terms and other similar words or expressions that are intended to identify forward-looking statements. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on Disc’s current beliefs, expectations and assumptions regarding the future of Disc’s business, future plans and strategies, clinical results and other future conditions. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements. Disc may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and investors should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements as a result of a number of material risks and uncertainties including but not limited to: the adequacy of Disc’s capital to support its future operations and its ability to successfully initiate and complete clinical trials; the nature, strategy and focus of Disc; the difficulty in predicting the time and cost of development of Disc’s product candidates; Disc’s plans to research, develop and commercialize its current and future product candidates; that enrollment timelines of both the BEACON and AURORA studies may not necessarily be predictive of future enrollment timelines; the timing of initiation of Disc’s planned clinical trials; Disc’s ability to retain and recognize the intended incentives conferred by Fast Track Designation for its product candidates including DISC-3405 and DISC-0974; Disc’s ability to retain and recognize the intended incentives conferred by Orphan Drug Designation for DISC-3405 and bitopertin; the timing of the availability of data from Disc’s clinical trials; Disc’s ability to identify additional product candidates with significant commercial potential and to expand its pipeline in hematological diseases; the timing and anticipated results of Disc’s preclinical studies and clinical trials and the risk that the results of Disc’s clinical trials may not be predictive of future results in connection with future studies or clinical trials and may not support further development and marketing approval; the other risks and uncertainties described in the “Risk Factors” section of our Annual Report on Form 10-K for the year ended December 31, 2023, and other documents filed by Disc from time to time with the SEC, as well as discussions of potential risks, uncertainties, and other important factors in Disc’s subsequent filings with the SEC. Any forward-looking statement speaks only as of the date on which it was made. None of Disc, nor its affiliates, advisors or representatives, undertake any obligation to publicly update or revise any forward-looking statement, whether as result of new information, future events or otherwise, except as required by law. DISC MEDICINE, INC. CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS(In thousands, except share and per share amounts) ​Year Ended December 31, ​ 2023 ​ 2022 Operating expenses:​ ​ Research and development​$69,264 ​$33,437 General and administrative​ 21,861 ​ 14,038 Total operating expenses​ 91,125 ​ 47,475 Loss from operations​ (91,125)​ (47,475)Other income (expense), net 14,795 ​ 648 Income tax expense​ (99) — Net loss​$(76,429)​$(46,827)Weighted-average common shares outstanding-basic and diluted​ 22,315,877 1,039,490 Net loss per share-basic and diluted​$(3.42)​$(45.05) DISC MEDICINE, INC. CONDENSED CONSOLIDATED BALANCE SHEETS (In thousands) ​December 31, December 31, ​ 2023 ​ 2022 Assets​ ​ Cash and cash equivalents​$360,382 ​$194,611 Other current assets​ 5,280 ​ 3,880 Total current assets​ 365,662 ​ 198,491 Non-current assets​ 2,334 1,714 Total assets​$367,996 ​$200,205 Liabilities and Stockholders’ Equity​ ​ Current liabilities​$21,439 ​$22,578 Non-current liabilities​ 1,436 ​ 1,027 Total liabilities​ 22,875 ​ 23,605 Total stockholders’ equity​ 345,121 ​ 176,600 Total liabilities and stockholders’ equity​$367,996 ​$200,205 Media Contact Peg RusconiVerge Scientific Communicationsprusconi@vergescientific.com Investor Relations Contact Christina TartagliaStern Investor Relationschristina.tartaglia@sternir.com

Consistent and dose-dependent reductions of protoporphyrin IX (PPIX), the disease-causing metabolite in EPP, were observed in patients treated with bitopertin Patients reported significant improvements in sunlight tolerance and measures of quality-of-life Bitopertin was well-tolerated, with no meaningful changes in hemoglobin observed Disc Medicine to host an investor conference call today at 7:30 AM ET WATERTOWN, Mass., June 09, 2023 (GLOBE NEWSWIRE) -- Disc Medicine, Inc. (NASDAQ:IRON), a clinical-stage biopharmaceutical company focused on the discovery, development, and commercialization of novel treatments for patients suffering from serious hematologic diseases, today presented preliminary findings from its ongoing, Phase 2 open-label BEACON trial evaluating bitopertin, an orally administered glycine transporter 1 (GlyT1) inhibitor, in patients with erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) at the European Hematology Association (EHA) 2023 Congress in Frankfurt, Germany. The initial trial data demonstrated consistent decreases in PPIX, significant increases in reported sunlight tolerance and improvements in measures of patient quality of life. “We’re delighted to share these initial, positive data from BEACON, which provide the first clinical evidence supporting our therapeutic hypothesis of bitopertin in EPP. Over the next 12 months, we plan to build on this momentum with a series of additional clinical read-outs across our portfolio,” said John Quisel, J.D., Ph.D., Chief Executive Officer and President of Disc Medicine. “This is an important moment for Disc as a company, and I want to extend my gratitude to our team, collaborators, and most importantly, the patients and families participating in BEACON.” “We are excited to share these initial data from the BEACON trial, where we observed consistent and sustained suppression of PPIX, the disease-causing metabolite in EPP, in patients treated with bitopertin,” said Will Savage, M.D., Ph.D., Chief Medical Officer at Disc Medicine. “Importantly, this reduction translated into significant improvements in the time that patients can spend in sunlight without reporting pain or symptoms related to their disease. We’re encouraged by the data and plan to present additional data at the end of the year.” The BEACON trial is a randomized, open-label, parallel-arm trial enrolling up to 22 patients with EPP or XLP at trial sites in Australia. This trial was designed to assess changes in levels of PPIX, as well as measures of photosensitivity, quality of life, and safety and tolerability. Subjects are randomized to receive either 20 mg or 60 mg of bitopertin once-daily for 24 weeks, after which patients have the option of continuing in an open-label extension of the trial for up to an additional 24 weeks. The trial is ongoing and these data reflect initial data from 15 subjects enrolled as of the data cutoff of May 8, 2023, with a range of treatment durations from 18 days to 6 months. Due to batch processing of samples, the data cutoff for PPIX data was April 7, 2023. Highlights of the initial data presented: Protoporphyrin IX (PPIX) levels: Significant, consistent, dose-dependent, and sustained reductions of whole-blood, metal-free PPIX; mean reduction of >40% when compared to baseline Measures of light tolerance (individual) from two participants with the longest follow-up demonstrated substantial increases in sunlight tolerance as measured by time in sunlight without experiencing a prodrome (initial symptoms that signal a pain attack), or “sunlight challenge”: A participant on 20 mg bitopertin reported a >80-fold increase in sunlight tolerance on day 88 of treatment, increasing from 4.5 minutes at baseline to over 6 hours; the participant did not report a prodrome during any sunlight challenge after Day 20 A participant on 60 mg bitopertin reported a >200-fold increase in sunlight tolerance on day 74 of treatment, increasing from 1.25 minutes at baseline to over 4 hours, and did not report a prodrome during any sunlight challenge after Day 120 Measures of light tolerance (aggregated across participants from whom data was available in the trial): Average weekly total time spent in sunlight: increased from 344 minutes (approximately 49 minutes per day) to 1,200 minutes at Week 24 Time to prodrome during sunlight challenge (averaged over a two-week period): increased >7-fold, from 25 minutes at baseline to 182 minutes at Week 24 Increased proportion of days without symptoms: 75% vs. 25% (baseline) Increased proportion of sunlight challenges without prodromes: 50% vs. 0% (baseline) Phototoxic reactions: 96% reduction in patient-reported phototoxic reactions while on treatment compared to baseline (n=15) Measures of patient quality of life Patient Global Impression of Change (PGIC): All 10 patients that had completed a day 43 visit reported their disease was much better (n=8) or a little better (n=2) in the last 7 days Patient Global Impression of Severity (PGIS): Nine out of 10 patients that had completed a day 43 visit reported their EPP was mild (n=3) or not at all severe (n=6) EPP Impact Questionnaire (EPIQ): For patients whose most recent data was Day 43, 4/8 patients reported an improvement in the impact of EPP on quality of life and 4/8 reported no change in the impact of EPP on quality of life. For patients whose most recent data was after Day 43, 2/2 reported marked improvement in the impact of EPP on quality of life, reporting no impact of EPP on quality of life. Bitopertin was well-tolerated at both dose levels with no reported serious adverse events, no reported discontinuations or dose reductions, no reported adverse events greater than Grade 1, and no meaningful changes observed in mean hemoglobin levels These data were presented at the European Hematology Association 2023 Congress in Frankfurt, Germany and the poster is available on the EHA Congress platform at . Management will host a call to review the presented data on Friday, June 9th at 7:30 am ET. Please register for the event on the Events and Presentations page of Disc’s website ( ). About Bitopertin Bitopertin is an investigational, clinical-stage, orally-administered inhibitor of glycine transporter 1 (GlyT1) that is designed to modulate heme biosynthesis. GlyT1 is a membrane transporter expressed on developing red blood cells and is required to supply sufficient glycine for heme biosynthesis and support erythropoiesis. Disc is planning to develop bitopertin as a potential treatment for a range of hematologic diseases including erythropoietic porphyrias, where it has potential to be the first disease-modifying therapy. There are currently two ongoing Phase 2 clinical trials of bitopertin in patients with erythropoietic porphyria, including an open-label trial called BEACON and a randomized, double-blind placebo-controlled trial called AURORA. Bitopertin is an investigational agent and is not approved for use as a therapy in any jurisdiction worldwide. Disc obtained global rights to bitopertin under a license agreement from Roche in May 2021. About Erythropoietic Protoporphyria (EPP) and X-linked Protoporphyria (XLP) Erythropoietic protoporphyria (EPP) and X-linked Protoporphyria (XLP) are rare, debilitating and potentially life-threatening diseases caused by mutations that affect heme biosynthesis, resulting in the accumulation of a toxic, photoactive intermediate called protoporphyrin IX (PPIX). This causes severe reactions when patients are exposed to sunlight, characterized by excruciating pain, edema, burning sensations and potential blistering and disfigurement. PPIX also accumulates in the hepatobiliary system and can result in complications including gallstones, cholestasis, and liver damage in 20-30% of patients and in extreme cases liver failure. Current standard of care involves extreme measures to avoid sunlight, including restricting outdoor activities to nighttime, use of protective clothing and opaque shields, and pain management. This has a significant impact on the psychosocial development, quality of life, and daily activities of patients, particularly in young children and families. There is currently no cure for EPP and only one FDA-approved therapy, a surgically implanted synthetic hormone designed to stimulate melanin production called Scenesse® (afamelanotide). About Disc Medicine Disc Medicine is a clinical-stage biopharmaceutical company committed to discovering, developing, and commercializing novel treatments for patients who suffer from serious hematologic diseases. We are building a portfolio of innovative, potentially first-in-class therapeutic candidates that aim to address a wide spectrum of hematologic diseases by targeting fundamental biological pathways of red blood cell biology, specifically heme biosynthesis and iron homeostasis. For more information, please visit Disc Medicine Cautionary Statement Regarding Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including, but not limited to, express or implied statements regarding Disc’s expectations with respect to its BEACON Phase 2 clinical trial of bitopertin and projected timelines for the initiation and completion of its clinical trials, the timing of additional data and other activities. The use of words such as, but not limited to, “aim,” “believe,” “expect,” “estimate,” “project,” “intend,” “future,” “potential,” “continue,” “may,” “might,” “plan,” “will,” “should,” “seek,” “anticipate,” or “could” or the negative of these terms and other similar words or expressions that are intended to identify forward-looking statements. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on Disc’s current beliefs, expectations and assumptions regarding the future of Disc’s business, future plans and strategies, clinical data and other future conditions. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements. Disc may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and investors should not place undue reliance on these forward-looking statements. Actual data or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements as a result of a number of material risks and uncertainties including but not limited to: the adequacy of Disc’s capital to support its future operations and its ability to successfully initiate and complete clinical trials; the nature, strategy and focus of Disc; the difficulty in predicting the time and cost of development of Disc’s product candidates; Disc’s plans to research, develop and commercialize its current and future product candidates; the timing of initiation of Disc’s planned preclinical studies and clinical trials; the timing of the availability of data from Disc’s clinical trials; Disc’s ability to identify additional product candidates with significant commercial potential and to expand its pipeline in hematological diseases; the timing and anticipated data of Disc’s preclinical studies and clinical trials and the risk that the data of Disc’s preclinical studies and clinical trials may not be predictive of future data in connection with future studies or clinical trials and may not support further development and marketing approval; the other risks and uncertainties described in the “Risk Factors” section of our Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) on May 15, 2023 and other documents filed by Disc from time to time with the SEC, as well as discussions of potential risks, uncertainties, and other important factors in Disc’s subsequent filings with the SEC. Any forward-looking statement speaks only as of the date on which it was made. None of Disc, nor its affiliates, advisors or representatives, undertake any obligation to publicly update or revise any forward-looking statement, whether as result of new information, future events or otherwise, except as required by law. Media Contact Peg Rusconi Verge Scientific Communications prusconi@vergescientific.com Investor Relations Contact Christina Tartaglia Stern Investor Relations christina.tartaglia@sternir.com

Two ongoing Phase 2 studies of bitopertin in EPP; initial safety and efficacy data from open-label BEACON trial to be presented at the European Hematology Association (EHA) Congress in June 2023; topline data from both BEACON and AURORA studies expected by end of 2023Two separate, ongoing Phase 1b/2 studies of DISC-0974 in patients with anemia of chronic kidney disease who are not receiving dialysis (NDD-CKD) and also in patients with myelofibrosis and anemia; interim data expected by end of 2023In-licensed anti-TMPRSS6 monoclonal antibodies from Mabwell Therapeutics; Phase 1 trial expected to start 2H 2023Completed $62.5 million financing led by Bain Capital Life Sciences WATERTOWN, Mass., May 15, 2023 (GLOBE NEWSWIRE) -- Disc Medicine, Inc. (NASDAQ:IRON), a clinical-stage biopharmaceutical company focused on the discovery, development, and commercialization of novel treatments for patients suffering from serious hematologic diseases, today reported financial results for the first quarter ending March 31, 2023 and provided an update on recent program and corporate developments. “We have had an excellent start to 2023 with each of our development programs on-track; multiple clinical studies ongoing, including new indications such as CKD anemia and Diamond-Blackfan anemia; and growing our pipeline by in-licensing a third, Phase-1 ready program,” said John Quisel, J.D., Ph.D., President and Chief Executive Officer of Disc. “We are positioned to deliver a series of important catalysts across our portfolio through the rest of 2023 and into next year, beginning with the presentation of initial data from the BEACON study at EHA.” Recent Business Highlights and Upcoming Milestones: Bitopertin: GlyT1 Inhibitor (Heme Synthesis Modulator) Bitopertin is an investigational, clinical-stage, orally-administered inhibitor of glycine transporter 1 (GlyT1) that is designed to modulate heme biosynthesis. GlyT1 is a membrane transporter expressed on developing red blood cells and is required to supply sufficient glycine for heme biosynthesis and support erythropoiesis. Disc is planning to develop bitopertin as a potential treatment for a range of hematologic diseases including erythropoietic porphyrias, where it has potential to be the first disease-modifying therapy. Continued enrollment of BEACON, an open-label Phase 2 clinical study of bitopertin in patients with EPP and X-linked protoporphyria (XLP). Interim data will be presented at EHA Congress on June 9, 2023, with an accompanying management call at 7:30 am ET the same day.Disc expects topline data from BEACON by end of 2023. Continued enrollment for AURORA, a Phase 2 randomized, placebo-controlled clinical study of bitopertin in adults with EPP. Disc expects topline data from AURORA by end of 2023.Received a positive opinion on Orphan Designation for bitopertin for treatment of EPP from the European Committee for Orphan Medical Products in January 2023. Orphan Drug Designation was previously granted by the FDA in 2022.Announced a collaboration with NIH to study bitopertin in patients with Diamond-Blackfan Anemia in March 2023; the study is expected to initiate mid-year 2023. DISC-0974: Anti-Hemojuvelin Antibody (Hepcidin Suppression) DISC-0974 is an investigational anti-hemojuvelin monoclonal antibody (mAb) and is designed to suppress hepcidin production and increase serum iron levels in patients suffering from anemia of inflammation. Initiated and enrollment is ongoing for a Phase 1b/2 clinical study of patients with anemia of chronic kidney disease who are not receiving dialysis (NDD-CKD) in February 2023; interim data expected by end of 2023Continued enrollment in a Phase 1b/2 clinical study in MF patients with severe anemia on stable background therapy; interim data expected by end of 2023 MWTX-003: Anti-TMPRSS6 Antibody (Hepcidin Induction) MWTX-003 is an investigational, anti-TMPRSS6 (Transmembrane Serine Protease 6, also known as Matriptase-2) monoclonal antibody designed to increase hepcidin production and suppress serum iron. Entered into an exclusive licensing agreement with Mabwell Therapeutics in January 2023 to obtain an exclusive license to rights outside of Greater China for a portfolio of monoclonal antibodies targeting TMPRSS6 including a Phase 1-ready drug candidate, MWTX-003.The IND was accepted in November 2022 and Disc plans to initiate a Phase 1 study of MWTX-003 in healthy volunteers during the second half of 2023.Disc plans to develop MWTX-003 initially as a treatment for polycythemia vera as well as other indications. Corporate: Completed a $62.5 million registered direct offering of our common stock led by Bain Capital Life Sciences, with participation from Access Biotechnology and OrbiMed, in February 2023. First Quarter 2023 Financial Results: Cash Position: Cash and cash equivalents were $236.4 million as of March 31, 2023 compared to $194.6 million as of December 31, 2022. The increase was due to $62.5 million in gross proceeds from a registered direct offering led by Bain Capital Life Sciences in February 2023, as well as $15.0 million in gross proceeds from ATM offerings completed in Q1 2023. Disc expects its cash and cash equivalents to fund its operational plans into 2025.Research and Development Expenses: R&D expenses were $20.2 million for the quarter ending March 31, 2023, as compared to $7.8 million for the quarter ending March 31, 2022. The increase in R&D expenses were primarily driven by a one-time $10.0 million upfront payment under the Mabwell license agreement and the progression of Disc’s portfolio, including increased headcount, the advancement of DISC-0974 into an additional Phase 1b/2 clinical study, and bitopertin’s ongoing two Phase 2 clinical studies.General and Administrative Expenses: G&A expenses were $4.9 million for the quarter ending March 31, 2023, as compared to $2.1 million for the same period in 2022. The increase in G&A expenses was primarily due to increased headcount and legal and market research costs.Net Loss: The net loss was $22.8 million for the first quarter of 2023, as compared to $9.9 million for the first quarter of 2022. The increase was primarily due to higher operating costs in the current period to support the continued advancement of the Company’s pipeline. About Disc Medicine Disc Medicine (NASDAQ:IRON) is a clinical-stage biopharmaceutical company committed to discovering, developing, and commercializing novel treatments for patients who suffer from serious hematologic diseases. We are building a portfolio of innovative, potentially first-in-class therapeutic candidates that aim to address a wide spectrum of hematologic diseases by targeting fundamental biological pathways of red blood cell biology, specifically heme biosynthesis and iron homeostasis. For more information, please visit www.discmedicine.com. Available Information Disc announces material information to the public about the Company, its products and services, and other matters through a variety of means, including filings with the U.S. Securities and Exchange Commission (SEC), press releases, public conference calls, webcasts and the investor relations section of the Company website at ir.discmedicine.com in order to achieve broad, non-exclusionary distribution of information to the public and for complying with its disclosure obligations under Regulation FD. Disc Cautionary Statement Regarding Forward-Looking Statements This press release contains “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995, including, but not limited to, express or implied statements regarding Disc’s expectations with respect to its AURORA Phase 2 and BEACON Phase 2 clinical studies of bitopertin, and anticipated study of bitopertin in Diamond-Blackfan Anemia, its Phase 1b/2 clinical study of DISC-0974 in NDD-CKD patients with anemia, its anticipated Phase 1 study of MWTX-003 and potential development of MWTX-003 as a treatment for polycythemia vera and other indications, projected timelines for the initiation and completion of its clinical trials, anticipated timing of release of data, and other clinical activities; Disc’s business plans and objectives; and Disc’s beliefs about operating expenses and that it will have capital to fund Disc into 2025. The use of words such as, but not limited to, “believe,” “expect,” “estimate,” “project,” “intend,” “future,” “potential,” “continue,” “may,” “might,” “plan,” “will,” “should,” “seek,” “anticipate,” or “could” or the negative of these terms and other similar words or expressions that are intended to identify forward-looking statements. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, they are based on Disc’s current beliefs, expectations and assumptions regarding the future of Disc’s business, future plans and strategies, clinical results and other future conditions. New risks and uncertainties may emerge from time to time, and it is not possible to predict all risks and uncertainties. No representations or warranties (expressed or implied) are made about the accuracy of any such forward-looking statements. Disc may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and investors should not place undue reliance on these forward-looking statements. Actual results or events could differ materially from the plans, intentions and expectations disclosed in the forward-looking statements as a result of a number of material risks and uncertainties including but not limited to: the adequacy of Disc’s capital to support its future operations and its ability to successfully initiate and complete clinical trials; the nature, strategy and focus of Disc; the difficulty in predicting the time and cost of development of Disc’s product candidates; Disc’s plans to research, develop and commercialize its current and future product candidates; the timing of initiation of Disc’s planned preclinical studies and clinical trials; the timing of the availability of data from Disc’s clinical trials; Disc’s ability to identify additional product candidates with significant commercial potential and to expand its pipeline in hematological diseases; the timing and anticipated results of Disc’s preclinical studies and clinical trials and the risk that the results of Disc’s preclinical studies and clinical trials may not be predictive of future results in connection with future studies or clinical trials and may not support further development and marketing approval; the other risks and uncertainties described in the “Risk Factors” section of our Annual Report on Form 10-K for the year ended December 31, 2022 and other documents filed by Disc from time to time with the Securities and Exchange Commission, as well as discussions of potential risks, uncertainties, and other important factors in Disc’s subsequent filings with the Securities and Exchange Commission. Any forward-looking statement speaks only as of the date on which it was made. None of Disc, nor its affiliates, advisors or representatives, undertake any obligation to publicly update or revise any forward-looking statement, whether as result of new information, future events or otherwise, except as required by law. DISC MEDICINE, INC. CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (In thousands, except share and per share amounts) (Unaudited) ​Three Ended March 31, ​ 2023 ​ 2022 Operating expenses:​ ​ Research and development​$20,180 ​$7,821 General and administrative​ 4,945 ​ 2,139 Total operating expenses​ 25,125 ​ 9,960 Loss from operations​ (25,125)​ (9,960) Other income (expense), net 2,367 ​ 107 Income tax expense​ (23)​ — Net loss​$(22,781)​$(9,853) Weighted-average common shares outstanding-basic and diluted​ 18,954,914 ​ 923,750 Net loss per share-basic and diluted​$(1.20)​$(10.67) DISC MEDICINE, INC. CONDENSED CONSOLIDATED BALANCE SHEETS (In thousands) (Unaudited) ​March 31, December 31, ​2023​2022 Assets​ ​ Cash and cash equivalents​$236,422​$194,611 Other current assets​ 5,716​ 3,880 Total current assets​ 242,138​ 198,491 Non-current assets​ 1,642 1,714 Total assets​$243,780​$200,205 Liabilities and Stockholders’ Equity​ ​ Current liabilities​$9,980​$22,578 Non-current liabilities​ 945​ 1,027 Total liabilities​ 10,925​ 23,605 Total stockholders’ equity​ 232,855​ 176,600 Total liabilities and stockholders’ equity​$243,780​$200,205 Media Contact Peg RusconiVerge Scientific Communicationsprusconi@vergescientific.com Investor Relations Contact Suzanne Messere Stern Investor Relationssuzanne.messere@sternir.com