SILVER SPRING, Md. -- An FDA advisory committee has voted 13-7 that the modest weight-loss benefits of an investigational combination of naltrexone and bupropion (Contrave) outweigh the drug's blood pressure risk. 
 
 The bupropion naltrexone combo is the last in a trio of new weight-loss drugs that went before FDA panels this year, striving to be the latest treatment in the dwindling field of medications to fight obesity. The previous two drugs, phentermine/topiramate (Qnexa) and lorcaserin hydrochloride (Lorqess) were both rejected by the FDA after they fared poorly at advisory committee meetings. 
 
 But Tuesday's advisory committee ended very differently than the previous two. 
 
 Bupropion/naltrexone appeared to offer fewer side effects than the previous two drugs, although it also doesn't appear to work as well at helping obese patients lose weight. 
 
 The FDA will make an approval decision by Jan. 31. The agency does not have to follow the advice of its advisory committees, but it often does. 
 
 Orexigen, the company that makes naltrexone/bupropion in partnership with Takeda, is seeking approval for treatment of obesity and weight management in patients with a body mass index of 30 or above, or 27 or above and with one or more risk factors (e.g., diabetes, dyslipidemia, or hypertension). 
 
 Contrave combines an antidepressant and an anti-addiction drug, both of which have been used individually for 20 years -- naltrexone for opioid addiction and alcohol dependence and bupropion for depression and smoking cessation. However, little is known about combining the drugs for weight managment. 
 
 The Endocrine and Metabolic Drugs Advisory Committee reviewed results from Orexigen's four placebo-controlled, one-year, phase III clinical trials, which enrolled 3,200 obese patients with at least one comorbid condition, including diabetes and depression. 
 
 In all four trials, patients on the naltrexone/bupropion combination lost more weight than those in the placebo group (P<0.001), and more than 30% lost at least 5% of their body weight, which is one standard by which the FDA judges efficacy of weight-loss drugs. 
 
 In a pooled analysis, naltrexone/bupropion patients lost an average of 4.2% more weight than the placebo group (ranging from 3.3% to 4.8%). That falls short of the other FDA standard that after one year, the difference in mean weight loss between the active and control groups should be at least 5%. 
 
 In one trial where patients taking naltrexone/bupropion were compared with those undergoing a lifestyle modification program, the difference between the groups was even smaller, suggesting that diet and exercise can achieve similar results as naltrexone/bupropion. 
 
 "As far as efficacy goes, I think they made it by the hair of their chinny chin chin," said Melanie Coffin, the panel's patient representative. 
 
 In the FDA's assessment of the drug released last week, reviewers expressed concerns over several side effects -- a potential increased risk for dizziness, nausea, seizures, and high blood pressure among patients taking naltrexone/bupropion. 
 
 However, the panel was mostly just concerned with one side effect: The drug's effect on blood pressure. 
 
 In the trials, patients taking naltrexone/bupropion were more likely to have an increase in blood pressure and heart rate than placebo patients, an effect that was most pronounced during the first eight weeks of treatment. 
 
 However, patients taking naltrexone/bupropion who lost at least 5% of their body weight achieved lower blood pressure and heart rate compared with those who lost less weight. But the most impressive improvements in blood pressure and weight loss were seen among patients taking placebo who achieved more than a 5% weight loss, suggesting diet and exercise is the best option for obese patients to lower their blood pressure. 
 
 Panelists were concerned that a drug that is supposed to reduce obesity -- and hopefully other comorbidities along with it -- actually raised blood pressure instead. 
 
 "This is my biggest concern," said Lamont Weide, MD, PhD, chief of diabetes and endocrinology at Truman Medical Centers Diabetes Center in Kansas City, Mo. "That we are blunting all the good effects that we should see with weight loss." 
 
 The FDA reviewers concluded there wasn't enough data on the cardiovascular risks of the drug. The panel seemed to agree, but voted 11-8, with two panelists abstaining, that the company could submit new data after approval to show that the drug doesn't present major heart risks. 
 
 The panel's one neurologist, Michael Rogawski, MD, PhD, said he thought the panel downplayed the drug's seizure risk. 
 
 Two patients in the clinical trials experienced seizures after going on naltrexone/bupropion; no participants in the placebo group had seizures. About one in 1,000 patients who take the drug would be expected to have a seizure, the panelists said. 
 
 "They occur only in one out of 1,000, but still, the consequences of having a seizure could be catastrophic," said Rogawski, who ended up voting in favor of the drug. 
 
 There is currently just one anti-obesity drug on the market: Orlistat (Xenical, Alli), after Abbott, the maker of another drug sibutramine (Meridia) voluntarily agreed to remove it from the U.S. market in October because of increased risk of stroke and MI. 
 
 Several physicians and other healthcare professionals contacted by MedPage Today/ABC News were pleased with the panel's decision and said that doctors badly need a new drug to help patients battle obesity. 
 
 "It is nice to have a medication that can help those who are watching their diet and boosting activity lose the weight that thus far has been a slow process," said dietitian Connie Diekman, director of University Nutrition at Washington University in St Louis. "This is one more option in the tool chest to deal with the obesity issue." 
 
 "Finally!" said Robert F. Kushner, MD, professor of Medicine at Northwestern University Feinberg School of Medicine. "I fully endorse the panel's vote. The key will be to educate physicians on how to best prescribe the medication -- identify patients who will benefit from the medication and to accompany it with lifestyle and behavioral recommendations." 
 
 Paul L. Doering, a pharmacy professor at the University of Florida, said he doesn't "doubt for a minute that this drug will be wildly successful, at least at first," adding, "Time will ultimately tell if it is a good drug or not. In the meantime, I'm going to let somebody else be the first to take it." 
 
 This article was developed in collaboration with ABC News. ||||| The Food and Drug Administration has approved Arena Pharmaceutical's anti-obesity pill Belviq, the first new prescription drug for long-term weight loss to enter the U.S. market in over a decade. 
 
 This photo provided by Food and Drug Administration shows Arena Pharmaceutical's anti-obesity pill Belviq. The Food and Drug Administration has approved Belviq, the first new prescription drug for long-term... (Associated Press) 
 
 Despite only achieving modest weight loss in clinical studies, the drug appeared safe enough to win the FDA's endorsement, amid calls from doctors for new weight-loss treatments. 
 
 The agency cleared the pill Wednesday for adults who are obese or are overweight with at least one medical complication, such as diabetes or high cholesterol. 
 
 The FDA denied approval for Arena's drug in 2010 after scientists raised concerns about tumors that developed in animals studied with the drug. The company resubmitted the drug with additional data earlier this year, and the FDA said there was little risk of tumors in humans. 
 
 "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 FDA's drug center director, Dr. Janet Woodcock, in a statement. 
 
 Arena and its partner Eisai Inc. of Woodcliff Lake, N.J., expect to launch the drug in early 2013. 
 
 With U.S. obesity rates nearing 35 percent of the adult population, many doctors have called on the FDA to approve new weight loss treatments. 
 
 But a long line of prescription weight loss offerings have been associated with safety problems, most notably the fen-phen combination, which was linked to heart valve damage in 1997. The cocktail of phentermine and fenfluramine was a popular weight loss combination prescribed by doctors, though it was never approved by FDA. 
 
 In a rare move, the FDA explicitly stated in a press release that Belviq "does not appear to activate" a chemical pathway that was linked to the heart problems seen with fen-phen. 
 
 The FDA said the drug acts on a different chemical pathway in the brain, which is believed to reduce appetite by boosting feelings of satiety and fullness. 
 
 Obesity Society President Patrick O'Neil said he's encouraged by the drug's approval because it underscores the idea that lifestyle changes alone are not enough to treat obesity. 
 
 "This is good news because it tells us that the FDA is indeed treating obesity seriously. On the other hand, it's not the answer to the problem _ or even a big part of the answer," said O'Neil, who teaches at Medical University of South Carolina and was the lead researcher on several studies of Belviq. 
 
 Even if the effects of Belviq are subtle, experts say it could be an important first step in a new line of treatments that attack the underlying causes of obesity. 
 
 "The way these things tend to work is you have some people who do extremely well and other people don't lose any weight at all. But if we had 10 medicines that were all different and worked like this, we would have a real field," said Dr. Louis Aronne, director of the weight loss program at Weill-Cornell Medical College. 
 
 Belviq is one of three experimental weight-loss drugs whose developers have been trying for a second time to win approval, after the FDA shot them all down in 2010 or early 2011 because of serious potential side effects. 
 
 Vivus Inc.'s Qnexa is thought to be the most promising of the drugs, achieving the most weight loss. But the FDA has delayed a decision on that pill until July. 
 
 Shares of San Diego-based Arena Pharmaceuticals Inc. jumped $2.54, or 28.7 percent, to close at $11.39. Shares of Mountain View, Calif.-based Vivus rose $1.94, or 7.4 percent, to $28.33. 
 
 Arena's studies showed that patients taking Belviq, known generically as lorcaserin, had modest weight loss. On average patients lost just 3 to 3.7 percent of their starting body weight over a year. About 47 percent of patients without diabetes lost at least 5 percent of their weight or more, which was enough to meet FDA standards for effectiveness. By comparison, average weight loss with Qnexa is 11 percent, with more than 83 percent of patients losing 5 percent of their weight or more. 
 
 The FDA said patients should stop taking Belviq after three months if they fail to lose 5 percent of their body weight. Patients are unlikely to see any significant weight loss by staying with the drug. 
 
 Side effects with the drug include depression, migraine and memory lapses. 
 
 In May a panel of expert advisers to the FDA voted 18-4 to recommend approval of Arena's drug, concluding that its benefits "outweigh the potential risks when used long term" in overweight and obese people. 
 
 Experts say the challenge of weight loss drug development lies in safely turning off one of the body's fundamental directives: to eat enough food to maintain its current weight. 
 
 While several drugs are available for short-term weight loss, until Wednesday there was only one FDA-approved prescription drug for long-term weight loss: Xenical from Roche, which is seldom prescribed because of unpleasant digestive side effects and modest weight loss. Belviq is the first new prescription drug approved to treat obesity since Xenical's approval 13 years ago. 
 
 Other safety failures for diet pills have continued to pile up in recent years. 
 
 Four years ago Sanofi-Aventis SA discontinued studies of its highly anticipated pill Acomplia due to psychiatric side effects, including depression and suicidal thoughts. In 2010, Abbott Laboratories withdrew its drug Meridia after a study showed it increased heart attack and stroke.
– A rarity in the weight wars: An FDA advisory panel gave the green light today to a diet pill that could become the first such drug to hit the market in more than a decade. The FDA is expected to make a final decision next month on Contrave, though it generally follows the advice of its panels. Made by Orexigen Therapeutics—whose shares were soaring, notes Bloomberg—Contrave has what MedPage Today describes has "modest" weight-loss effects. Panel members thought the benefit outweighed potential side effects such as high blood pressure. Contrave is a combination of two drugs already on the market: bupropion, an antidepressant also used to quit smoking, and naltrexone, which is used to treat addictions to alcohol and painkillers. One pharmacy professor tells MedPage Today he's sure it will be a huge success initially. "Time will ultimately tell if it is a good drug or not," he adds. "In the meantime, I'm going to let somebody else be the first to take it."