The US FDA has issued a complete response (CRL) to Disc Medicine's new drug application (NDA) for bitopertin for the treatment of erythropoietic protoporphyria (EPP).[1][2] The application sought expedited approval under the FDA Commissioner's National Priority Coupon Pilot Program.[1][4] The FDA acknowledged that the AURORA and BEACON studies demonstrated significant reductions in whole blood metal-free PPIX, including approximately a 40% decrease in the high-dose arm.[1][3][5] However, the agency concluded that there was no evidence of a relationship between PPIX change and outcomes related to sunlight exposure.[1][2][3] The FDA requires the results of the ongoing Phase 3 APOLLO trial for traditional approval.[1][2][3] APOLLO enrollment was completed in March 2026, with top-line data expected in Q4 2026 and an FDA review decision in mid-2027.[1][2][3] The company is planning a Type A meeting with the FDA and a response to the CRL.[1]