Sanofi has decided to halt all clinical trials and cancel plans for regulatory filings with its investigational JAK2 inhibitor, fedratinib (SAR302503).

Following a thorough risk-benefit analysis, including consultation with the US Food and Drug Administration (FDA), study investigators, independent expert neurologists and neuro-radiologists, Sanofi determined that the risk to patient safety outweighed the benefit that fedratinib would bring to patients.

This decision follows recent reports of cases consistent with Wernicke’s encephalopathy in patients participating in fedratinib clinical trials. The FDA directed Sanofi to put all fedratinib trials on clinical hold while the company thoroughly investigated these cases to ensure the safety of fedratinib for patients. Sanofi took immediate action requesting that study investigators discontinue fedratinib treatment for patients in the trials.

“We are deeply disappointed to have to discontinue development of fedratinib, especially given the needs of this difficult-to-treat patient population and the earlier promise shown for this therapy, but patient safety is our top priority and drove this decision,” said Tal Zaks, MD, PhD, VP, head of Development and Interim Head of Sanofi Oncology.

Sanofi has notified investigators of all ongoing fedratinib trials, as well as health authorities, of its decision to halt the trials. Patients currently in fedratinib trials should consult with their treating physician to determine the best alternative course of therapy for their myelofibrosis.

Fedratinib is a novel, investigational JAK2 inhibitor that was under development by Sanofi Oncology for the treatment of the three main types of myeloproliferative neoplasms: primary myelofibrosis, including those previously treated with ruxolitinib; polycythemia vera; and essential thrombocythemia.

Sanofi Oncology, a global division of Sanofi, is dedicated to the discovery, development and delivery of effective therapeutics that address unmet medical need for cancer patients.

Sanofi, an integrated global healthcare leader, discovers, develops and distributes therapeutic solutions focused on patients’ needs. Sanofi has core strengths in the field of healthcare with seven growth platforms: diabetes solutions, human vaccines, innovative drugs, consumer healthcare, emerging markets, animal health and the new Genzyme.