Biohaven Pharmaceutical, a clinical-stage biopharmaceutical company, announced that BHV-5000, an investigational compound in the company's glutamate modulation platform, has been granted orphan drug designation by the US Food and Drug Administration (FDA) for the treatment for patients with Rett syndrome.  This is the company's fourth product candidate to receive orphan drug designation from the FDA.

Rett syndrome is a rare and severe genetic neurodevelopmental disorder affecting females almost exclusively. Symptoms emerge from six to 18 months of age after apparently normal post-natal development. Patients with Rett syndrome develop global deceleration of psychomotor function, loss of acquired cognitive skills (such as language and purposeful hand movement) as well as brain-mediated episodes of transient respiratory suppression. Patients may survive into adulthood, yet they are severely physically and cognitively impaired. Rett syndrome affects approximately 15,000 individuals in the United States. No approved drug therapies for Rett syndrome are currently available and care is supportive.

"BHV-5000 is a novel glutamate antagonist that Biohaven plans to evaluate for efficacy across several therapeutic indications," said Vlad Coric, M.D., chief executive officer of Biohaven. "Our clinical development program in Rett syndrome is particularly important because patients and their families currently have no approved drugs for this severe neurodevelopmental disorder. The orphan drug designation for BHV-5000 in Rett syndrome supports Biohaven's global development strategy of providing improved therapies for patients suffering from some of the most disabling neurologic disorders."

Potential benefits of orphan drug designation include tax credits for 50% of clinical trial costs, waiver of marketing application user fees (estimated at over $2 million in savings) and 7 years of marketing exclusivity if regulatory approval is ultimately received.

"Patients with Rett syndrome develop debilitating symptoms," said Robert Berman, M.D., chief medical officer of Biohaven.  "Preclinical studies on BHV-5000 have demonstrated benefits in transgenic mouse models of Rett syndrome, particularly on symptoms of abnormal breathing.  We are eager to test BHV-5000 in patients with Rett syndrome to understand if these preclinical effects translate into therapeutic benefits for patients."   

Biohaven expects to initiate a Phase 1 trial of BHV-5000 in healthy volunteers with a commercially-ready formulation in 2017, and then proceed to a study in patients with Rett syndrome in 2018.