Disc Medicine (IRON) shares climbed to $79.23 in Wednesday trading, following a fireside chat at the Wells Fargo 21st Annual Healthcare Conference on September 10, where CEO John Quisel and analyst Derek Archila outlined the company's two leading programs.
DISC-3405, a monoclonal antibody against TMPRSS6 designed to restrict iron and curb excess red blood cell production, is being studied in a Phase II trial split into two cohorts of 20 patients each. Cohort A tested a biweekly dosing schedule with a dose run-in adjustment; Cohort B evaluates once-every-four-weeks dosing. Enrollment was completed ahead of schedule, with Cohort B data expected by year-end, followed by an end-of-Phase II meeting and a path toward Phase III.
In Cohort A, phlebotomy rates fell from roughly four procedures per unit time to 0.6—an approximate 85% reduction. About 60% of patients achieved phlebotomy-free status at some point during the trial, and 7 of 9 patients (78%) who reached a stable long-term dose were phlebotomy-free. The program showed minimal anemia and virtually no injection-site reactions, according to Quisel.
The U.S. polycythemia vera market includes roughly 150,000 patients, of whom 50,000 to 100,000 are managed with phlebotomy. Disc Medicine is positioning DISC-3405 as a potential frontline therapy intended to displace hydroxyurea, with interferons and JAK inhibitors reserved for more severe disease. A separate open-label trial in sickle cell disease is evaluating a small number of patients, with case report data anticipated by year-end.
Bitopertin, the company's most advanced candidate for erythropoietic protoporphyria (EPP), has top-line data from the APOLLO Phase III trial slated for the fourth quarter. The trial enrolled 183 patients—above the original target of 150—with the last patient enrolled in March 2024 and the final visit in September 2024 after a six-month treatment period. Co-primary endpoints are protoporphyrin IX levels and time spent in light at month 6, measured via a handheld device tracking daily exposure between 10 a.m. and 6 p.m.
Phase III was powered at more than 80%, using an 11-hour effect size—an approximately 26% discount from the 14.9-hour Phase II result at month 4—with a standard deviation of roughly 24 hours. A blinded sample-size re-estimation in January 2024 based on the first 50 completers confirmed variability matched Phase II expectations.
The FDA issued a complete response letter in early 2024 after prior accelerated-approval efforts, stating that the surrogate endpoint of protoporphyrin IX did not clearly predict clinical benefit. Disc had been selected for the Commissioner's National Priority Voucher.
Massachusetts General Hospital estimates suggest around 20,000 U.S. patients with EPP, though the core approachable population is estimated at 3,000 to 6,000. About 150 patients are already on the drug through extension and expanded-access studies, with roughly 600 more seen at trial-site centers of excellence. Competitors include Clinuvel's SCENESSE, requiring a surgical implant, and oral terapia dersimelagon. Disc is retaining approximately half of its commercial sales force and medical science liaisons in preparation.
Disc Medicine, valued at $2.94 billion, remains pre-revenue and unprofitable with a negative EBITDA of $268 million over the trailing twelve months. Its current ratio stands at 24.14, with cash exceeding debt. The stock has gained 28% over the past year and carries a beta of 2.05. Analyst price targets range from $79 to $128, with six analysts recently revising earnings estimates upward.
