Zafgen, a Boston-based biotech firm, released data revealing an experimental obesity drug called beloranib was successful in treating patients with a rare illness known as Prader-Willi syndrome (PWS).

PWS is a disorder that can cause a number of physical, mental, and behavioral issues at birth. One prominent symptom of the disease is hyperphagia, a condition that induces a voracious appetite leading to severe obesity, or even death.

Zafgen’s trial had 107 participants, according to Xconomy.The researchers randomly assigned high (2.4 mg) or low (1.8 mg) doses of beloranib to patients twice a week for six months.

Study participants who took the high dose lost an estimated 5.3 percent of their body weight whereas the low-dose recipients lost 4.05 percent, adds Xconomy.

Zafgen faced a big setback last year when two patients died during a late-stage study of beloranib.Regulators insisted Zafgen put a hold on conducting further research in order to figure out next steps. Its stock plunged a little more than 60 percent in December.

The company said on Wednesday it would submit efficacy and safety data to the Food and Drug Administration (FDA) from the study, writes Reuters. It plans on doing more research regarding the impact beloranib has on blood-clotting capabilities to discern its potential risks to patients.

Shares of Zafgen were up 78 percent in premarket trading.