A second patient has died in a late-stage clinical trial testing Zafgen Inc.’s experimental obesity drug beloranib , just two months after the Food and Drug Administration (FDA) halted part of the study to investigate what may have caused the first death.
The second death occurred in an arm of the trial that was testing beloranib on patients with Prader-Willi Syndrome, a rare genetic disorder that causes constant, extreme hunger often resulting in life-threatening obesity. The patient was diagnosed with bilateral pulmonary emboli – blood clots in the lungs – during treatment, and subsequently died.
In October, Zafgen informed the FDA that a patient had died during a trial on beloranib. The agency placed a partial clinical hold on the study while it investigated the unknown nature of the patient’s death. The agency also cited reports of thromboembolic events, or potentially life-threatening blood clots in the blood vessels, in patients in other ongoing and completed studies on the drug.
Beloranib is designed to make the body produce less fat and burn off excess fat as fuel. It works by blocking methionine aminopeptidase 2, an enzyme that plays a key role in the production and use of fatty acids. Zafgen was testing beloranib as a treatment for Prader-Willi Syndrome, as well as other weight-related disorders.
Obesity treatments have traveled a rocky road with the federal government over the years, with many treatments pulled or slapped with warning labels because of heart risks, liver damage, increased suicidal thoughts, and birth defects. The most recent weight loss treatments to receive FDA approval have been granted clearance only if the companies agree to collect additional safety data on patients taking the drug.
Zafgen says it is working with the FDA to determine next steps for beloranib, and expects to have “top-line results” of the randomized arm of the clinical trial by the first quarter of 2016.