for erythropoietic protoporphyria (EPP)
FDA issued a Complete Response Letter for the bitopertin NDA in EPP on February 13, 2026. The application sought Accelerated Approval; specific deficiency details would require sponsor 8-K review.
Erythropoietic protoporphyria (EPP) is a disorder that causes severe, painful skin reactions after even brief exposure to sunlight due to a buildup of a light-sensitive molecule called protoporphyrin. Bitopertin is an oral drug designed to inhibit the glycine transporter 1 (GlyT1), which is thought to reduce the overproduction of protoporphyrin in red blood cells. By lowering protoporphyrin levels, this approach could potentially allow people with EPP to spend more time outdoors without triggering painful attacks.
The goal of this clinical trial is to learn if bitopertin works and is safe to treat EPP or XLP in participants 12 years or older. The main questions it aims to answer are: * Whether bitopertin increases pain-free sunlight exposure after 6 months of treatment in participants with EPP or XLP
Source: ClinicalTrials.gov