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BOSTON — A once-promising treatment for obesity is now all but abandoned, as the biotech company that developed the drug scrapped efforts to bring it to market after it was tied to two patient deaths.

Zafgen announced Tuesday it will lay off a third of its workforce, about 16 people, as it pivots to focus on a different experimental drug in an earlier stage of development. Management hopes the new product can spur weight loss without the same safety issues.

Just last year, the Boston firm was among the biotech industry’s star class of young companies. Its drug, beloranib, had generated positive clinical data for patients with a rare binge-eating disorder, and Zafgen was pushing toward Food and Drug Administration approval with a late-stage trial.


But things came apart in October when the company disclosed that a patient in the trial had died. Weeks later, Zafgen disclosed a second death, and the FDA put all development of beloranib on hold. Both deaths came from respiratory failure, the company said, as patients developed blood clots in their lungs.

Now Zafgen is setting beloranib aside, giving up hope of getting the program back on track. The drug is still under an FDA hold, and Zafgen determined that the costs and obstacles of restarting research are too great to justify spending any more money on it.


Instead, Zafgen is turning its attention to a therapy called ZGN-1061, which is now in the first phase of clinical development. The company expects to have safety data on ZGN-1061 next year and will decide then whether to push it forward.

Zafgen’s share price has fallen more than 90 percent since October. Its market value peaked in March of 2015 at $1.4 billion.

The company went public in 2014, amid a surge of optimism in the biotech sector, raising $96 million in the process. It was part of wave of companies seeking new ways to target obesity, amid predictions that new treatments to boost metabolism and melt away fat would become huge sellers. Yet that market has crashed, with drug after drug failing to catch on among physicians and the public.

Correction: An earlier version of this story misstated the number of employees to be laid off at Zafgen.