Disc Medicine is laying off a fifth of its workforce as the biotech reels from the FDA’s rejection of its rare blood disease candidate.
Last month, the agency knocked back an approval application for the glycine reuptake inhibitor bitopertin in erythropoietic protoporphyria (EPP) and X-linked protoporphyria. The FDA took issue with the use of a surrogate endpoint in place of clinical outcomes for the phase 2 study that formed the bulk of Disc’s approval application.
In response to this news, Disc is shrinking its head count by 20%, the biotech disclosed in a Feb. 27 filing with the Securities and Exchange Commission. The layoffs, which Disc expects to be completed in the second quarter, will primarily affect commercial roles and “certain supporting functions,” the company said.
Massachusetts-based Disc entered the new year with 155 full-time employees, according to its annual report, meaning about 30 workers are likely to be affected.
Disc licensed bitopertin in 2021 from Roche, which had been testing the drug predominantly in psychiatric disorders such as schizophrenia. The phase 2 trial at the center of Disc’s approval application enrolled 75 patients with EPP, a rare genetic disease in which molecules called protoporphyrins build up in red blood cells, causing pain when exposed to sunlight. The condition can also lead to liver disease.
In both the randomized, placebo-controlled trial as well as an open-label study that was also included in the submission, Disc used a drop in levels of protoporphyrin IX (PPIX) as the primary endpoint. In its rejection, the FDA agreed that both trials achieved their goals but called the 40% change in PPIX seen in the randomized trial’s high-dose arm “relatively modest.”
The regulator argued that neither trial showed evidence that lowered PPIX levels correlated with an improved tolerance of the sun, “despite the strong mechanistic and biological plausibility” of a connection.
The rejection was part of a recent trend of FDA rebuffs, particularly in rare diseases. Another company on the receiving end of these refusals was Regenxbio’s Hunter syndrome gene therapy, where the agency raised concerns about several trial design features that would typically have been addressed much earlier in the regulatory process.
Despite its own FDA rejection, Disc isn’t ready to give up on bitopertin. In its annual report last week, the biotech pointed out that the regulator indicated results of an ongoing phase 3 trial could provide the evidence needed to support approval.
Top-line data from that study—which is set to enroll about 150 patients and is using sun exposure outcomes as primary endpoints—are expected in the fourth quarter. Once it has this data, Disc plans to respond to the FDA’s rejection letter.