May 10, 2012 (Silver Spring, Md.) -- An FDA advisory committee voted 18-4, with one abstention, that the agency should approve lorcaserin, which would make it the first new prescription weight loss drug in more than a decade.
Although the FDA does not have to follow the advice of its advisory panels, it usually does.
Arena Pharmaceuticals wants to market lorcaserin for weight loss and maintenance in obese adults whose body mass index, or BMI, is at least 30, and in overweight adults with a BMI of at least 27 who also have one or more weight-related medical problems, such as high blood pressure, heart disease, sleep apnea, or type 2 diabetes. A 5-foot-7-inch person who weighs 192 has a BMI of 30; at 173 pounds, a person that height has a BMI of 27.
Concerns about heart valve problems helped spur the advisory panel to vote 9-5 against recommending approval of lorcaserin in September 2010. Committee members' other safety concerns included psychiatric problems such as psychosis and breast and brain tumors seen in rats given the drug. Meanwhile, patients who took lorcaserin lost only a bit more weight than those given a placebo.
In October 2010, the FDA turned down lorcaserin, citing the modest weight loss and worries about its potential to cause cancer. In response, Arena submitted more material to the agency, including a trial of the drug in 604 patients with type 2 diabetes.
After a year in the study, diabetes patients given lorcaserin lost 3.1% more weight than those on a placebo, below the 5% difference the FDA has set as one criterion for weight loss drugs, FDA medical officer Julie Golden, MD, said.
However, she said, lorcaserin did meet the other criterion: After a year of treatment, 38% of patients on lorcaserin lost at least 5% of their body weight, compared to 16% of those on placebo.
Although he voted in favor of approval, Jack Yanovski, MD, PhD, chief of the section on growth and obesity at the Eunice Kennedy Shriver National Institute of Child Health and Human Development, said he was "not at all convinced" that Arena had provided enough evidence to show that lorcaserin did not raise the risk of breast tumors.
In addition, "there is still a lingering uncertainty" about the connection between lorcaserin and heart valve disease, said panelist Sanjay Kaul, MD, a UCLA cardiology professor who voted against approving the drug. ''Given the totality of evidence, the potential benefits of [the drug] do not outweigh the potential risks."
Doctors who spoke in the public hearing emphasized the need for additional treatment methods for obesity other than diet and exercise on one hand and surgery on the other.
''We need a broader spectrum of tools -- something between cutting calories and cutting the GI tract," said Domenica Rubino, MD, an obesity specialist from Arlington, Va.
Risks of Untreated Obesity
And the doctors noted that untreated obesity carries its own risks.
"There can be no doubt. Untreated obesity harms every body system," said Northwestern University obesity specialist Robert Kushner, MD, representing the Obesity Society, of which Arena is a corporate member.
Lisa Sutter of the Washington, D.C., area told committee members that she had participated in a phase II trial of lorcaserin from 2007 to 2009.
"It was amazing," said Sutter. "My brain switched back to normal again."
In a year, she said, she lost 40 pounds, about 20% of her starting weight. But for the second year of the study, she was taken off the drug. "So now I'm back to where I was, and more," she said.
The FDA is expected to make a decision about lorcaserin by June 27.