FDA Rejects Disc Medicine’s Porphyria Drug Bitopertin in First Test of Makary Fast-Track Program

The Food and Drug Administration rejected bitopertin, a treatment for porphyria developed by Disc Medicine, on Friday, sending the biotech firm’s stock price down 31% to $49 in afternoon trading. The decision marks the first rejection under a new fast-track review program initiated by FDA Commissioner Marty Makary.

The FDA cited “uncertainties” regarding the link between a blood-based biomarker used to measure efficacy in Disc Medicine’s clinical trials and actual clinical improvement for patients. The agency posted the rejection letter publicly on Friday afternoon, according to reports.

Bitopertin was intended to treat porphyria, a group of rare genetic disorders that cause extreme sensitivity to sunlight and can lead to debilitating pain, skin blistering and organ damage. The drug’s development represented a significant effort to address a condition with limited treatment options.

Makary’s fast-track program, launched with the aim of accelerating the review of promising therapies, previously approved a generic antibiotic in December. The rejection of bitopertin raises questions about the program’s effectiveness and the criteria used for selecting drugs for expedited review.

Disc Medicine was an early recipient of a priority review voucher under Makary’s leadership, a program designed to incentivize the development of drugs for rare diseases. According to reporting by Stat News, nine companies have received these vouchers since Makary’s appointment. The FDA’s decision on bitopertin comes after a period of increased scrutiny regarding the agency’s use of these vouchers.

The FDA’s rejection of bitopertin follows recent approval of Cytokinetics’ heart drug, marking the biotech’s first FDA-approved product. This approval highlights the contrasting fortunes within the biotech sector, with some companies achieving regulatory success while others face setbacks.

Patients who had hoped for access to bitopertin, and who had experienced relief from their symptoms during clinical trials, now face uncertainty about their future treatment options. A recent Stat News report detailed the experiences of patients who had been able to live more normal lives thanks to the drug, and who now fear losing that benefit.