Disc Medicine Announces Success on All Primary and Secondary Endpoints in the Pivotal Phase 3 APOLLO Trial of Bitopertin in Adults and Adolescents with Erythropoietic[...]

Disc Medicine Announces Success on All Primary and Secondary Endpoints in the Pivotal Phase 3 APOLLO Trial of Bitopertin in Adults and Adolescents with Erythropoietic Protoporphyria (EPP)

WATERTOWN, Mass., October 19, 2026 - 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 announced topline results from the APOLLO Phase 3 trial of bitopertin in erythropoietic protoporphyria (EPP), including X-linked protoporphyria (XLP). The trial met all its primary and secondary endpoints.

"Today represents a potential breakthrough in the science and treatment of EPP," said John Quisel, J.D., Ph.D., President and Chief Executive Officer of Disc Medicine. "We could not have hoped for a better outcome, and we are grateful to the patients, caregivers, and physicians who have partnered with us throughout the clinical development of bitopertin. We look forward to engaging with regulators with the goal of bringing an important, innovative medicine to this community as efficiently as possible."

"This is the first time a potential treatment for EPP has shown robust evidence of whole blood PPIX reduction alongside unequivocal improvement on important measures of disease severity: increased time in light, reduced phototoxic reactions, and improved Patient Reported Outcome scores," said Herbert L. Bonkovsky, M.D., Director of Gastroenterology & Internal Medicine, Professor Emeritus of Medicine at Wake Forest University School of Medicine, and a Principal Investigator of APOLLO.

"These results are compelling evidence of the clinical benefit of a mechanism aimed at reducing the production of PPIX, the fundamental cause of disease," added Will Savage, M.D., Ph.D., Chief Medical Officer of Disc Medicine. "It has been an incredible journey from establishing the original hypothesis of targeting heme synthesis in cellular models to seeing that biology translate into the clear and meaningful clinical effects from APOLLO. We plan to share more detailed data with additional insights from APOLLO at a future medical conference."

APOLLO is a randomized, double-blind pivotal Phase 3 trial evaluating the safety and efficacy of bitopertin versus placebo in adults and adolescents aged 12 or older with EPP or XLP. The trial enrolled 183 patients across the United States, Canada, Europe, and Australia, who were stratified by baseline light tolerance and geography and randomized 1:1 to receive 60 mg oral bitopertin or placebo once daily for 6 months.

Summary of topline results:

The APOLLO study adds to an extensive clinical data package supporting bitopertin's potential in EPP. Based on these results, Disc plans to resubmit a New Drug Application (NDA) to the U.S. FDA by the end of 2026, with an FDA decision anticipated by mid-2027.

Management will host a corporate webcast this morning, Monday, October 19 at 8:00am EST to discuss the APOLLO topline results and next steps. Please register for the event on the Events and Presentations page of Disc's website (https://ir.discmedicine.com/).

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. Bitopertin has been studied in multiple clinical trials in patients with EPP, including the Phase 2 open-label BEACON trial, the Phase 2 double-blind, placebo-controlled AURORA trial, the open-label extension HELIOS trial, and the APOLLO trial.

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 EPP

Erythropoietic protoporphyria (EPP), including X-linked Protoporphyria (XLP), is a rare, debilitating and potentially life-threatening disease 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 www.discmedicine.com.

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