FDA Delays Decision on Orexigen's NB32 For Weight Loss

Orexigen Therapeutics announced in a press release that the Food and Drug Administration (FDA) has delayed its decision on NB32 for weight loss. The company had submitted a revised New Drug Application (NDA), and the FDA was expected to approve or decline the application. Instead, the FDA delayed its decision giving the new Prescription Drug User Fee Act (PDUFA) action date for September 11, 2014. Orexigen stated that the FDA needed more time to evaluate cardiovascular (CV) outcomes and post-marketing studies. Michael Narachi, CEO of Orexigen, said, "We are working expeditiously with the FDA to finalize the review. We are encouraged by the high level of engagement with the FDA, and are confident that we can reach agreement on the remaining post-marketing obligation."

FDA Action

Orexigen’s NDA includes CV outcome data and interim safety reports from the Light Study involving almost 9,000 people. The FDA stated that the delay in its decision is due to its need to review that data. The FDA also wishes to work closely with the company to design post-marketing studies. Additionally, discussions are still underway regarding the package insert. According to Forbes, the company and the FDA are discussing warnings on the label about CV outcomes.

About NB32

NB32 is a fixed-dose combination of Orexigen’s proprietary SR version of naltrexone and bupropion sustained-release (SR). Buproprion increases dopamine activity, which may lead to appetite reduction. Additionally, due to POMC neuron activity, the patient may increase energy expenditure. The two action mechanisms may lead to weight loss. Orexigen states that the drug reduces appetite, helps control cravings, increases metabolism, and improves control over eating behaviors.

In clinical trials, NB32 helped people lose weight and keep it off for up to one year. Half of participants lost five percent of their bodyweight over 12 months compared to the 21 percent who lost five percent body weight in the placebo group. People in a six month program taking NB32 along with a structured weight management program lost an average of 25 pounds. The placebo group lost an average of 17 pounds. People who combined the drug with diet and exercise saw the most improvement.   

About Orexigen Therapeutics

Orexigen Therapeutics is a biopharmaceutical company whose lead candidate is NB32. Orexigen’s strategy for the drug is to pursue U.S. regulatory approval and expand regulatory applications worldwide. The company also wishes to form partnerships for global commercialization. In the U.S., if the drug is approved, Takeda will commercialize NB32. Another Orexigen drug is Empatic, which is currently in Phase II trials.