Biopharmaceutical company Zafgen announced that the Phase III trial of its experimental obesity drug Beloranib for Prader-Willi syndrome (PWS) has achieved co-primary efficacy endpoints.

The PWS ZAF-311 study led to significant weight-loss and improved hyperphagia-related behaviors in PWS patients.

Around 107 patients were given subcutaneous injections of either 2.4mg or 1.8mg of beloranib or a placebo twice a week.

74 completed the full 26 weeks of treatment as per the trial protocol, while 27 patients completed at least 75% of the randomised treatment period prior to the suspension of dosing in October 2015.

"We now have the robust data to provide greater perspective on the benefit/ risk relationship of beloranib in this high-risk patient population."

Patients treated with 2.4mg and the 1.8mg doses of beloranib experienced 9.45% and 8.20% reductions in body weight relative to placebo, respectively.

The 2.4mg and the 1.8mg doses of beloranib reduced hyperphagia-related behaviors by 7.0 units and 6.3 units relative to placebo, respectively.

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.

The results might help convince the Food and Drug Administration (FDA) to remove the agency’s clinical hold on the treatment.

The hold was due to an imbalance in severe venous thromboembolic events, including two patient deaths.

PWS is a common genetic cause of life-threatening obesity. It causes pathologic hunger-related behaviors, known as hyperphagia.

Other symptoms include slowed metabolism, higher risk for cardiopulmonary and metabolic co-morbidities, and psychiatric conditions including aggression, anxiety, and psychosis.