Memorandum
Today, Zafgen announced that the company received verbal notice from the FDA that its beloranib investigational new drug (IND) application has been placed on complete clinical hold, thus suspending the ongoing open label extension (OLE) portion of the phase 3 ZAF-311 best PWS trial in patients with Prader-Willi syndrome (PWS). This follows the day’s earlier news of the death of a patient receiving beloranib in the study’s OLE, who was also diagnosed with bilateral pulmonary emboli. This is the second patient death in the study following a patient death in the beloranib arm this past October. However, Zafgen continues to expect top-line results of the double-blind, randomized portion of the ZAF-311 clinical trial in 1Q16 as management shared ongoing plans to “assemble and analyze the data” from the trial. In addition, the company noted its work with PWS and thrombosis experts to develop a “comprehensive approach to better understand the incidence and mechanisms underlying thromboembolic disease in the setting of PWS.” There is certainly an incredibly high degree of unmet need in this patient population so we will be curious to see how the risk-benefit balance is assessed in this context, and whether or not these deaths are related to the study drug. While we need a medication to address PWS, patient safety must remain paramount – see our AHA coverage for some of the recent commentary we heard regarding beloranib. For the other latest updates on Zafgen’s clinical program, please see our coverage of the company’s 3Q15 call.
-- by Melissa An, Sarah Odeh, and Kelly Close