Weight Loss Pill Belviq Gets FDA Approval
The US Food and Drug (FDA) announced on Wednesday that it has approved the weight loss pill Belviq, for use in adults who are obese or overweight, as part of chronic weight management that includes a reduced calorie diet and exercise.
Belviq (lorcaserin hydrochloride), made by the Swiss pharma company Arena, is the first prescription diet drug to receive US federal approval in over a decade. It works by activating the serotonin 2C receptor in the brain, an effect that may help the patient feel full after eating smaller amounts of food and thereby eat less.
Dr Janet Woodcock, director of the Center for Drug Evaluation and Research at the FDA, told the press:
"Obesity threatens the overall well being of patients and is a major public health concern."
FDA says the drug is approved for use in adults who are obese, or adults who are overweight and have at least one weight-related condition, such as type 2 diabetes, high blood pressure, or high cholesterol.
"The approval of this drug, used responsibly in combination with a healthy diet and lifestyle, provides a treatment option for Americans who are obese or are overweight and have at least one weight-related comorbid condition," said Woodcock.
The agency defines obesity as having a BMI of 30 or over, and overweight as having a BMI under this but no less than 27. BMI stands for Body Mass Index, and equals weight in kilos divided by the square of height in metres.
BMI is used by health authorities and policymakers as a measure of body fat. According to the US Centers for Disease Control and Prevention (CDC), more than one in three of adult Americans is obese.
The approved label for Belviq recommends that patients stop using it if they fail to lose 5% of their body weight after 12 weeks of treatment, as "these patients are unlikely to achieve clinically meaningful weight loss with continued treatment," says the FDA in their announcement.
To arrive at their decision, the FDA reviewed the safety and effectiveness of the drug in three trials. The randomized, placebo-controlled trials lasted between 52 and 104 weeks and involved nearly 8,000 overweight and obese participants, some of whom had type 2 diabetes.
All the participants were treated with the pill (either Belviq or placebo) as part of a lifestyle modification program that also included reduced calorie dieting and counselling to increase physical activity.
The results showed that the participants who took Belviq for up to 12 months lost 3 to 3.7% more of their starting body weight than the participants who took placebo.
Of the participants treated with Belviq who did not have type 2 diabetes, 47% lost at least 5% of their body weight. This compared to only 23% of their counterparts treated with placebo.
There was a similar pattern in the patients who had type 2 diabetes: 38% of those on Belviq lost at least 5% of their body weight, compared with only 16% of those who took placebo. The diabetic patients on Belviq also showed favorable changes in blood sugar (glycemic control).
The most common side effects in non-diabetic patients are fatigue, dry mouth, nausea, headache, dizziness, and constipation. For diabetics the most common side effects are low blood sugar, back pain, headache, cough and fatigue.
A condition of the approval is that Arena conducts six post-marketing studies, including a long term heart trial to assess the impact of Belviq on the risk for major events such as heart attack and stroke.
Belviq should not be used during pregnancy, says the FDA. It may cause disturbances in attention or memory, and can also cause serious side effects when taken with certain medications such as some used in treatments for depression and migraine that increase serotonin levels or activate the relevant receptors.
In 1997, two weight loss drugs (fenfluramine and dexfenfluramine) were withdrawn because of evidence they were damaging heart valves, thought to be due to activation of the serotonin 2B receptor on heart tissue.
But the FDA said when used at the approved dose of 10 mg twice a day, Belviq does appear to activate this receptor.
"There was no statistically significant difference in the development of FDA-defined valve abnormalities between Belviq and placebo-treated patients," said the FDA, adding that the Belviq development program carried out echiocardiograms to assess heart valve function in nearly 8,000 patients.
However, the FDA recommends proceeding with caution when prescribing Belviq for patients with congestive heart failure: preliminary data suggests the drug may increase the number of serotonin 2B receptors in this group.
The agency could not say what effect the drug might have on patients with serious valvular heart disease because it has not been tested on this group.
Belviq is the first of two drugs the FDA is expected to approve for weight loss management: the other is Qnexa from Vivus. That decision is expected by mid-July.
Qnexa is thought to help obese people lose 10% of their body weight, again as part of a program that includes diet and exercise.
One expert suggests, should Qnexa also receive approval, the two drugs will spur a change in how obesity is viewed in the US.
Tim Church, who advises Vivus and is director of preventive medicine research at the Pennington Biomedical Research Center in Baton Rouge, describes the two drugs as "complete game changers" that will trigger a "paradigm shift" in attitude to obesity.
He told USA Today:
"We are going to start treating it [obesity] like a chronic disease. Insurance companies are going to start paying for these medications, and physicians are going to get extremely comfortable with these and other medications that impact weight."
Belviq is distributed in the US by Eisai Inc. of Woodcliff Lake, New Jersey.