Under the bestPWS ZAF-311 double-blind, placebo-controlled phase 3 trial, the company evaluated the safety and efficacy of beloranib in patients with Prader-Willi syndrome (PWS) in a six-month randomized treatment period.
Last month, the US Food and Drug Administration (FDA) placed beloranib investigational new drug (IND) application on complete clinical hold, citing an imbalance in various venous thromboembolic events, including the death of two patients.
The company said it would now give the FDA data from the trial so far, along with information from other clinical studies.
Zafgen CEO Thomas Hughes said: "This clear efficacy outcome is a crucial first step in moving discussions forward with the Food and Drug Administration regarding continued development of beloranib.
"While we take the previously reported adverse events very seriously, we now have the robust data to provide greater perspective on the benefit/risk relationship of beloranib in this high-risk patient population."
Beloranib inhibits MetAP2, an enzyme that changes the activity of key cellular processes that control metabolism.
The injectable small molecule therapy is thought to help reduce hunger and restore balance to fat metabolism, allowing calories to once again be used as a productive energy source.
Zafgen exclusively licensed beloranib from South Korea-based Chong Kun Dang Pharmaceutical Corporation.
US-based Zafgen is also developing ZGN-839, a liver-targeted MetAP2 inhibitor, to treat nonalcoholic steatohepatitis, abdominal obesity, and second-generation MetAP2 inhibitors.