Teva Pharmaceutical Industries Ltd and Xenon Pharmaceuticals Inc. jointly announced that the US Food and Drug Administration (FDA) has granted orphan-drug designation to the investigational drug XEN402 being developed for the treatment of pain associated with erythromelalgia (EM).

EM is a rare autosomal dominant condition characterized by debilitating spontaneous or easily evoked attacks of symmetrical burning pain in the feet and hands, typically associated with elevated skin temperature and erythema (redness of the skin). Symptoms are generally induced by exercise, prolonged standing, exposure to heat, and/or changes in humidity. The pain can be so severe that it can lead to suicide, and adequate treatment remains very challenging.

Orphan Drug Designation is granted by the FDA Office of Orphan Drug Products to novel drugs intended to treat rare disease or condition affecting fewer than 200,000 people in the US. This designation confers special incentives to the drug developer, including tax credits towards the cost of clinical trials, prescription drug user fee waivers and may entitle a period of seven years US market exclusivity upon FDA approval.

"We are very pleased to receive orphan drug designation for XEN402. Through development of this drug, we hope to address the significant unmet medical need for patients who suffer from chronic pain related to erythromelalgia,” said Dr. Michael Hayden, president of global R&D and Chief Scientific Officer for Teva Pharmaceutical Industries, Ltd. “XEN402, which inhibits the SCN9A sodium channel, is being developed as a non-opioid approach to pain management."

“The granting of this orphan-drug designation is another important milestone for our XEN402 development” said Simon Pimstone, President and CEO of Xenon. “Xenon was founded with a commitment to identifying novel targets and from these, novel drugs for difficult to treat rare diseases. We are excited by the promise XEN402 has shown in early proof-of-concept trials and are committed to its development as a novel therapy for the treatment of pain associated with erythromelalgia”.

XEN402 is a novel chemical entity that has been exclusively licensed worldwide to Teva Pharmaceutical Industries Ltd. XEN402 inhibits the SCN9A sodium channel. Data from a published phase II study, suggest that XEN402 may relieve the pain associated with erythromelalgia.