Risk-benefit litmus test
How Zafgen could find an approval path after a second death in beloranib trials
Beloranib's role in two deaths with concurrent thrombotic events will be difficult to elucidate in a condition whose biology is not well understood. However, if Zafgen Inc. can characterize and mitigate the risk through an improved screening and management protocol, patients with Prader-Willi syndrome may find the trade-off acceptable given their high unmet need and data showing a substantial weight loss benefit.
Until the first death in Zafgen's Phase III trial, which was disclosed on Oct. 14, there did not appear to have been any reason to expect an increased rate of thrombosis in patients treated with beloranib. There is no obvious biological link between thrombosis and beloranib's target, and thromboses were not flagged in clinical trials of a compound from Takeda Pharmaceutical Co. Ltd. that hit the same target and was dosed much higher for cancer. ...