FDA Delays Bitopertin Approval, Pushing Disc Medicine to 2027

Event summary

  • FDA issued a Complete Response Letter for bitopertin, delaying potential approval for EPP treatment.
  • FDA acknowledged PPIX reduction evidence but sought APOLLO trial results for traditional approval.
  • Topline data from APOLLO trial expected in Q4 2026, with updated FDA decision by mid-2027.
  • Disc Medicine has $791 million in cash as of December 31, 2025, with runway into 2029.
  • APOLLO trial enrollment completed in March 2026, ahead of schedule.

The big picture

The FDA's Complete Response Letter for bitopertin highlights the regulatory challenges in expedited approval pathways for rare disease treatments. Disc Medicine's reliance on the APOLLO trial results underscores the critical role of confirmatory data in securing traditional approval. The biopharmaceutical sector continues to face scrutiny over surrogate endpoints, particularly in conditions like EPP where clinical benefit correlation remains complex.

What we're watching

Regulatory Pathway
Whether APOLLO trial results will meet FDA standards for traditional approval.
Execution Risk
The pace at which Disc Medicine can navigate the FDA review process post-APOLLO.
Financial Runway
How Disc Medicine manages its $791 million cash position through 2029.