Summary: This is a Phase 2, multi-center, double-blind, placebo-controlled, parallel group study of bitopertin to evaluate the safety, tolerability, efficacy, and PPIX concentration change in participants with EPP. Participants may roll over to an open label extension portion after completing the double-blind treatment period.

Summary: Erythropoietic protoporphyria (EPP) and X-linked protoporphyria (XLP) result from genetic defects of heme biosynthesis that cause life-long, painful cutaneous sensitivity to light. The objective of this study is to determine the efficacy and safety of oral cimetidine administration for treatment of the protoporphyrias. Efficacy will be based on protoporphyrin levels, photosensitivity, and quality ...