Bitopertin (GlyT1 Inhibitor)
for Erythropoietic Porphyrias

Bitopertin is a clinical-stage, first-in-class, oral small molecule inhibitor of
glycine transporter 1 (GlyT1), a key target to modulate heme biosynthesis.
We are developing bitopertin to treat erythropoietic porphyrias, a family of
rare, genetically-driven hematologic diseases.

Regulation of Heme Synthesis

Bitopertin is an oral, potent and selective inhibitor of GlyT1, a key membrane transporter required to supply developing red blood cells with sufficient glycine to support erythropoiesis. Heme biosynthesis is a multi-step, enzymatic process that begins with glycine, which is a critical component of heme. By limiting glycine uptake, bitopertin has the ability to regulate downstream heme synthesis. These hematologic effects have been established in numerous preclinical and clinical studies of bitopertin.

Erythropoietic Porphyrias

Erythropoietic porphyrias (EPs) are a family of rare, debilitating and potentially life-threatening diseases caused by mutations that affect the heme synthesis pathway. This results in the toxic accumulation of byproducts called porphyrins, which are activated when patients are exposed to sunlight and result in excruciating pain, blistering and edema in the skin and damage in other tissues. There is currently no cure and current care involves taking extreme measures to avoid daylight, which has a tremendous impact on the lives of patients and their families.

Erythropoietic porphyrias comprise three subtypes: Erythropoietic protoporphyria (EPP), X-linked protoporphyria (XLPP), and Congenital Erythropoietic Porphyria (CEP)

Development Status

We are developing bitopertin as the potentially first disease-modifying therapy for patients with erythropoietic porphyrias. We have shown in preclinical disease models that inhibiting glycine uptake with bitopertin can significantly deplete levels of disease-causing porphyrins.

Bitopertin was in-licensed from Roche and previously studied in over 4,000 healthy volunteers and patients. While bitopertin has not been studied in EPs, its clinical safety profile and effects on heme synthesis have been extensively characterized. Disc intends to initiate a phase 2 study in patients with EPP and XLPP following discussions with regulatory authorities.