[Reuters]

* First of three new obesity drugs up for review July 15

* Vivus’ Qnexa targets patients with related health issues

* Arena, Orexigen seeking to sell rival drugs

* Pills would be first for weight-loss in a decade

* Effects of long-term use likely to be an issue

By Susan Heavey and Lisa Richwine

WASHINGTON, July 8 (Reuters) – The first of three new fat-fighting pills faces public scrutiny by U.S. regulatory advisers next week, as small biotechs target the growing number of obese Americans despite a checkered past for weight-loss drugs.

Vivus Inc (VVUS.O), Arena Pharmaceuticals Inc (ARNA.O) and Orexigen Therapeutics Inc (OREX.O) are trying to succeed where earlier efforts flopped after several weight-loss drugs were linked to serious side effects.

The U.S. Food and Drug Administration will seek input from outside advisers July 15 on Vivus’ pill, Qnexa, for use with diet and exercise. If approved, it would be the first new prescription weight-loss drug in a decade in the United States, where two out of every three people are overweight.

The FDA’s review by a panel of outside experts follows a troubled history with obesity pills that either never gained approval, were pulled from the market after sales began, or were slapped with severe warnings.

“The history of weight-loss drugs is such that it’s a no-brainer that the FDA is going to take each and every one to an advisory panel,” said analyst Ira Loss, who follows the agency for Washington Analysis Corp.

An advisory panel is one of the last hurdles in a drug’s route to market. The FDA will make the final decision, but usually follows the advice of its advisers.

Qnexa, which combines the appetite suppressant phentermine with the anti-seizure drug topiramate, aims to treat obese people and overweight patients with related health problems.

Vivus is trying to improve on the notorious “fen-phen” diet drug that combined fenfluramine with phentermine. While fenfluramine was withdrawn, phentermine is generally considered safe at low doses. Topiramate, sold generically and as Johnson & Johnson’s (JNJ.N) Topamax, is an anticonvulsant that can curb appetite.

MORE WEIGHT-LOSS DRUGS AHEAD

Rival products are not far behind.

Arena is seeking FDA approval for lorcaserin, a new type of drug that targets the part of the brain that controls metabolism and appetite. A public FDA meeting has been tentatively scheduled for Sept. 16, according to the company.

Orexigen has said the FDA will hold a Dec. 7 public review of its candidate, Contrave. A combination of naltrexone, used to fight alcohol and drug addiction, and the antidepressant bupropion, Contrave aims to target cravings, curb appetite and boost metabolism.

All three drugs, if they make it to market, would be a big boost for their relatively small makers.

Analysts expect Vivus’ Qnexa, if approved, to take in nearly $689 million in sales by 2014, according to consensus forecast data from Thomson Reuters.

Last year, the entire range of prescription and over-the-counter weight-loss drugs took in $381.5 million, according to data from IMS Health.

For the year to date, shares of Vivus have risen 15 percent, while Arena is up nearly 3 percent. Orexigen has fallen 42 percent.

By comparison, the Nasdaq Biotech Index .NBI has fallen nearly 5 percent.

A TROUBLED PAST

Roughly 68 percent of U.S. adults, or nearly 211 million, are overweight or obese, according to the U.S. Centers for Disease Control and Prevention. Of those, more than 105 million are considered obese.

Weight can be managed through diet and exercise, but some medicines also can help.

American Home Products Corp, later renamed Wyeth and since last year part of Pfizer Inc (PFE.N), marketed fen-phen until 1997, when fatal heart valve problems forced the diet cocktail off the market.

Thousands of lawsuits followed, costing Wyeth some $21 billion in legal expenses. The company’s other drug, Redux, also contained a related chemical dexfenfluramine and was also taken off the market in 1997.

Shortly after, the FDA approved Meridia, now sold by Abbott Laboratories (ABT.N). That drug carries warnings about high blood pressure and a risk of heart attack and stroke in cardiovascular patients. It is no longer sold in Europe.

Roche Holding AG’s (ROG.VX) Xenical has been available since 1999, and GlaxoSmithKline (GSK.L) markets a lower-dose, over-the-counter version called Alli. But it can cause serious liver problems, uncontrolled bowel movements and gas.

Last year, widely used Hydroxycut-brand diet supplements were pulled from store shelves after reports of liver damage.

The current options “are not that effective by themselves,” said Dr. Lawrence Cheskin, director of the Johns Hopkins Weight Management Center in Baltimore. He has served on an advisory board that provides input to Vivus.

SMALL COMPANIES TAKE ON BIG PROBLEM

The companies offering the new generation of pills hope theirs offer better results.

Side effects of the three potential new drugs include headaches, infection, nausea, constipation and dry mouth.

Orexigen Chief Executive Officer Michael Narachi said he was keeping an eye on the July 15 Vivus meeting to get a sense of the FDA’s latest stance on obesity products.

“The best-case scenario is all of these drugs get approved for some appropriate population,” he said. Each drug may be able to target a niche group, such as Contrave’s potential for obese patients who are also depressed.

Arena is pinning its hopes on the fact that its drug is the only one of the three to use an entirely new chemical.

“There’s clearly a need for better agents,” said Dominic Behan, Arena’s chief scientific officer and co-founder.

Representatives for Vivus declined to comment, except to say they expected the FDA to make its final decision by Oct. 28.

All three companies must prove their therapies will not repeat the past.

“Obesity is the Cape Hatteras of drug development,” Morningstar analyst Damien Conover said, “where all these ships wanted to go and they sunk.” (Reporting by Susan Heavey and Lisa Richwine; Additional reporting by Bill Berkrot in New York; Editing by Tim Dobbyn and Lisa Von Ahn)

VIVUS, Inc. (NASDAQ:VVUS), Sun Bancorp, Inc. (NASDAQ:SNBC) and H&R Block, Inc. (NYSE:HRB) are three notable analyst upgrades, downgrades and comments made during today’s session.

VIVUS Obesity Medication Looks Attractive

VIVUS, Inc. (VVUS, Free Analysis), a developer of therapeutic products for underserved markets, was initiated at an Outperform with a $20 price target by Wedbush ahead of the opening bell today. The analyst believes that the firm’s Qnexa will help define a new class of obesity medications and views it as one of the most attractive product-driven plays in the mid-cap biotech space.

VIVUS’s experimental weight loss drug, which pairs a stimulant with an epilepsy drug, has shown in studies that it can help patients lose weight and keep it off for a year. Moreover, the drug has even helped some patients lower their blood pressure. Qnexa is up for approval by the FDA in October and has demonstrated impressive results in the eyes of many analysts.

Sumfolio

There have not been any serious adverse effects reported during the trial. Researchers have reported over 60% of the men taking the 200mg dose where able to achieve sufficient erections for intercourse following treatment.

Vivus Chief Executive Leland Wilson said “This is the second Phase III study in which avanafil demonstrated efficacy, fast onset-of-action and was well tolerated,” said . ED is a common occurrence among men with diabetes Wilson added.

Vivus is also being closely watched on progress Qnexa, an obesity drug that is also shown to lower blood pressure which has two more late-stage trials to complete a trial cycle that will enlist a total of some 1,300 patients.

Excessive weight gain isn’t only unhealthy, it’s expensive. Nearly 10 percent of U.S. healthcare dollars are spent on obesity-related expenses.

That’s why there’s so much interest in a new weight loss pill called Qnexa, which is expected to hit the market this year.
When it comes to weight loss, we’ve always been taught there’s no such thing as a quick fix. That might be about to change with Qnexa, which could be the next blockbuster drug to fight not only obesity, but also high blood pressure, diabetes and high cholesterol.
“We believe we have the first product that actually treats the causes of these diseases,” said Peter Tam, president of VIVUS, a Silicon Valley biotech company which developed Qnexa.
“So far all the treatments that are available right now are able to achieve 3-5 percent weight loss. We are the first treatment that is capable of achieving 10-15 percent weight loss within one year,” said Tam.
Meg Evans took one of these pills every day for two years. Her results were dramatic.
I just started steadily losing weight. Every time I came in, the scale just went straight down,” said Evans.
“They were amazed – and happy. And I was just as happy,” said Dr. Michelle Look, family practice / VIVUS consultant.
Look is a lead investigator and a paid consultant for VIVUS.
“What’s important to me for my patients is that a drug is efficacious and safe. And that is what I’ve seen in my two years of experience with this drug,” said Look.
Qnexa is a combination of the stimulant phentermine, which used to be one-half of the recalled drug Phenfen, and its new partner the epilepsy drug Topamax.
Study participants were also put on a reduced calorie diet and told to exercise three times a week.
Evans lost 55 pounds, more than 20 percent of her body weight. On average, participants lost ten percent of their weight.
“Very good results. Definitely much higher than we’d seen in any other compound that had been previously approved,” said Michelle.

Only a few patients reported side effects, which included itching, dry mouth, constipation and altered taste.
Qnexa was submitted to the FDA in March and could be on the market later this year. If approved, it will be by prescription only.

“The CODHy clinical congress is an excellent opportunity for us to share the potential of Qnexa with the global medical community,” stated Wesley Day, vice president, clinical development at VIVUS. Dr. Garvey’s presentation illustrates the promise of Qnexa for the treatment of obesity and its effect on weight-related co-morbidities, including diabetes and high blood pressure. There is mounting clinical and scientific evidence solidifying the link between obesity and important cardiovascular and metabolic disease.  We are pleased to be able to share this exciting data at an international meeting.”

Following are details about the upcoming presentation:

Excerpt from Motley Fool Article

VIVUS has a lot riding on its obesity drug Qnexa, which has potentially huge profit potential due to the size (sorry) of its target market. Along with competitor Arena Pharmaceuticals (Nasdaq: ARNA) — who is hoping to grab a piece of the lucrative niche with its own lorcaserin — VIVUS is still waiting for an FDA decision for the drug. Qnexa is up for an FDA expert panel review in July, and many expect to hear a decision on both drugs by October. Some investors and analysts are already prognosticating on the future though — one Brean Murray Carret analyst is betting on an approval in October and his recent buy recommendation helped trigger a rally in shares. About 91% of the 296 CAPS members rating VIVUS now see it is as a market-beating investment.

By Denise Mann

WebMD Health News

May 4, 2010 (New York) — An experimental weight loss/blood pressure pill may pack a one-two punch against hunger and high blood pressure, one of the main health consequences of obesity, according to new research presented at the American Society of Hypertension’s 25th annual meeting in New York.

Taken once a day, Qnexa combines the appetite suppressant phentermine with the anti-seizure drug topiramate in a unique formulation. Data on this drug are slated to be reviewed this summer by an FDA advisory panel. The FDA is not obligated to follow the advice of its expert panels, but it usually does.

Phentermine quickly suppresses appetite, while the controlled-release topiramate decreases appetite and increases satiety throughout the day. “When the hunger comes back, the topiramate kicks in,” says study author Suzanne Oparil, MD, a professor of medicine, physiology, and biophysics and director of the vascular biology and hypertension program at the University of Alabama at Birmingham. Topiramate also has blood pressure-lowering effects, she says. Oparil is a consultant for Qnexa manufacturer Vivus.

The new analysis of three separate studies included more than 4,500 people. Researchers compared several doses of the new pill with placebo among severely obese adults, as well as overweight, nonobese people who had other health problems related to their weight, such as high blood pressure or metabolic syndrome, a cluster of risk factors that increase risk for diabetes and heart disease.

Overall, people who took the combination pill lost more weight than their counterparts who were given a placebo. The higher the dose, the more substantial the weight loss, and the more likely it was to be maintained over time, the study shows.

At six months, people who took the full dose of Qnexa once daily lost nearly 10% of their body weight; by one year, it was up to 10.4%. Those who took the medium dose of the pill lost 8% of their body weight at six months and 8.2% by one year. The people who took the lowest dose of the drug dropped about 5.1% of body weight at six months, and, on average, gained some back by one year.

The new drug also resulted in drops in systolic blood pressure — the upper number in a blood pressure reading — at one year.

A sub-analysis of people with high blood pressure showed that the new pill also helped reduce blood pressure in this group and allowed them to reduce the number of other blood pressure medications they were taking.

The new pill did have some side effects, including altered taste, constipation, dizziness, dry mouth, and headache. But “there were no surprises,” Oparil says.

“It was safe and efficacious across a broad patient population — some who were very obese and some who were less obese, but had metabolic syndrome or high blood pressure,” she says.

MOUNTAIN VIEW, Calif., May 3, 2010 /PRNewswire via COMTEX/ — VIVUS, Inc. (10.71, -0.04, -0.37%), a biopharmaceutical company dedicated to the development and commercialization of novel therapeutic products, today reported its highlights and financial results for the first quarter ended March 31, 2010.

First Quarter 2010 Highlights

On January 7, 2010, we announced positive results from a Phase 2 study evaluating the safety and efficacy of Qnexa, our investigational product candidate, for the treatment of obstructive sleep apnea, or OSA. This study demonstrated statistically significant improvement in the apnea/hypopnea index, or AHI, which is a measure of the severity of sleep apnea, in patients with OSA treated with Qnexa for 28 weeks. Qnexatreated patients on average had a 69% reduction in sleep apnea and hypopnea events as compared to patients on placebo (ITT-LOCF p <0.001 active vs. placebo).

On January 11, 2010, we announced new data from an analysis of the recently completed Phase 3 study, REVIVE TA-301, of avanafil, an investigational product candidate for the treatment of erectile dysfunction, or ED. Patients who attempted intercourse within 15 minutes of dosing were successful 67%, 69% and 72% of the time on 50, 100 and 200 mg of avanafil, respectively, as compared to 29% of the patients on placebo (p<0.05).

On March 1, 2010, we announced that the FDA had accepted for filing the New Drug Application, or NDA, for Qnexa for the treatment of obesity. The Endocrinologic and Metabolic Drugs Advisory Committee of the U.S. FDA is tentatively scheduled to review the NDA for Qnexa for the treatment of obesity on July 15, 2010. Further, the FDA has set October 28, 2010 as the Prescription Drug User Fee Act, or PDUFA, date whereby we may expect a response to the review of the NDA.

“The highlight of the quarter was the acceptance of the Qnexa NDA and the notification of the tentative Advisory Committee meeting on July 15, 2010. We look forward to discussing the results of the phase 3 studies with Advisory Committee,” stated Leland Wilson, chief executive officer of VIVUS. “Early in the quarter we reported positive results from the phase 2 study of Qnexa in obstructive sleep apnea, a serious unmet medical need. Obstructive Sleep Apnea is now the third potential indication for Qnexa and we are working with the FDA to design a phase 3 program. In addition we also reported new data from the first phase 3 avanafil study that showed efficacy in 15 minutes, further distinguishing the product from the existing oral ED therapies.”

First Quarter Results

Product revenues from the sale of MUSE in the first quarter of 2010 were $1.6 million as compared to $1.2 million in the first quarter of 2009 due to the increase in number of units sold in 2010 as compared to last year. Total revenue for the first quarter of 2010 was $1.7 million as compared to $22.2 million for the first quarter of 2009. The decrease in total revenue in the first quarter of 2010 compared to the first quarter last year was primarily due to the inclusion of deferred license revenue from the sale of Evamist in the first quarter of 2009. There was no deferred license revenue recognized in the first quarter of 2010 as the monthly Evamist deferred revenue recognition ended in May 2009.

Net loss for the first quarter of 2010 was $18.8 million, or $0.23 per share, compared to $6.8 million, or $0.10 per share, for the same period last year. The increase in net loss in the first quarter of 2010 as compared to the first quarter of 2009 predominantly results from the completion of the recognition of the Evamist deferred revenue in 2009 and to a lesser extent, decreased research and development spending due to the completion of the phase 3 clinical trials for Qnexa for the treatment of obesity.

Cash, Cash Equivalents and Available-for-Sale Securities

VIVUS had cash, cash equivalents and available-for-sale securities of $194.9 million at March 31, 2010, as compared to $207 million at December 31, 2009. The decrease in cash, cash equivalents and available-for-sale securities of $12.1 million is primarily due to cash used in operations and other net cash uses offset by proceeds of $1 million from the exercise of common stock options.

About VIVUS

VIVUS is a biopharmaceutical company developing innovative, next-generation therapies to address unmet needs in obesity, sleep apnea, diabetes and sexual health. The company’s lead investigational product in clinical development, Qnexa(R), has completed phase 3 clinical trials for the treatment of obesity and an NDA has been filed and accepted by the FDA, with an action date of October 28, 2010. Qnexa is also in phase 2 clinical development for the treatment of type 2 diabetes and obstructive sleep apnea. In the area of sexual health, VIVUS is in phase 3 development with avanafil, a potentially best-in-class PDE5 inhibitor for the treatment of erectile dysfunction. MUSE(R) (alprostadil), a first generation therapy for the treatment of ED, is already commercially available and generating revenue for VIVUS. For more information about the company, please visit www.vivus.com.

Note to Investors

As previously announced, VIVUS will hold a conference call and an audio webcast to discuss the first quarter financial results today, May 3, 2010, beginning at 1:30 p.m. Pacific Time. You can listen to this call by dialing 1-877-359-2916 and outside the U.S. 1-224-357-2386. A webcast replay will be available for 30 days and can be accessed at http://ir.vivus.com/.

Certain statements in this press release are forward-looking within the meaning of the Private Securities Litigation Reform Act of 1995. These statements may be identified by the use of forward-looking words such as “anticipate,” “believe,” “forecast,” “estimated” and “intend,” among others. These forward-looking statements are based on VIVUS’ current expectations and actual results could differ materially. There are a number of factors that could cause actual events to differ materially from those indicated by such forward-looking statements. These factors include, but are not limited to, substantial competition; uncertainties of patent protection and litigation; uncertainties of government or third party payer reimbursement; reliance on sole source suppliers; limited sales and marketing efforts and dependence upon third parties; risks related to the development of innovative products; and risks related to failure to obtain FDA clearances or approvals and noncompliance with FDA regulations. As with any pharmaceutical under development, there are significant risks in the development, regulatory approval and commercialization of new products. There are no guarantees that future clinical studies discussed in this press release will be completed or successful or that any product will receive regulatory approval for any indication or prove to be commercially successful. VIVUS does not undertake an obligation to update or revise any forward-looking statement. Investors should read the risk factors set forth in VIVUS’ Form 10-K for the year ended December 31, 2009 and periodic reports filed with the Securities and Exchange Commission.

MOUNTAIN VIEW, Calif., May 3 /PRNewswire-FirstCall/ — VIVUS, Inc. (Nasdaq: VVUS) today announced the appointment ofMichael P. Miller to the position of senior vice president and chief commercial officer. This newly created position, reporting directly to Leland Wilson, chief executive officer, will be responsible for building and leading the commercial efforts for Qnexa, if approved, for commercial use.  Mr. Miller brings 30 years of commercial and launch experience from executive positions in marketing, sales and business development in the pharmaceutical and biotechnology industries. He has played a central role in the launch, growth and success of multiple brands spanning specialty and primary care markets, and has managed business development activities and partnerships with several leading pharmaceutical companies.

Most recently, Mr. Miller served as vice president in the BioOncology Business Unit at Genentech, a wholly owned member of the Roche Group, where he presided over three marketing teams and sales forces and drove top-line growth and successful indication launches for leading oncology therapies Herceptin®, Tarceva®, and Xeloda® to $2.5 billion combined revenue in 2009.  He was also responsible for the pre-launch activities of multiple pipeline products and the U.S. commercial collaboration with OSI Pharmaceuticals. Previously, Mr. Miller was senior vice president and chief commercial officer of Connectics Corporation.  He also served as vice president at ALZA Corporation, a Johnson & Johnson Company, where he launched Ditropan XL® and negotiated partnerships with companies including UCB Pharma, Inc., Abbott Laboratories, Inc. and Bayer Corporation.

“Mike brings significant specialty and primary care experience to our management team,” said Leland Wilson, chief executive officer, VIVUS. “Mike has the strategic vision, leadership skills, and track record for success as we evaluate potential partners and begin to formalize commercial plans for Qnexa, our investigational product candidate for the treatment of obesity.”

Prior to ALZA, Mr. Miller also held senior sales and marketing executive positions at VIVUS and Syntex Laboratories.  Mr. Miller holds a BS from the University of San Francisco and an MBA from San Francisco State University.

About VIVUS

VIVUS is a biopharmaceutical company developing innovative, next-generation therapies to address unmet needs in obesity, sleep apnea, diabetes and sexual health.  The company’s lead investigational product candidate, Qnexa®, has completed phase 3 clinical trials for the treatment of obesity and an NDA has been submitted and accepted by the FDA, with an action date of October 28, 2010. Qnexa is also in phase 2 clinical development for the treatment of type 2 diabetes and obstructive sleep apnea.  In the area of sexual health, VIVUS is in phase 3 development with avanafil, a potentially best-in-class PDE5 inhibitor for the treatment of erectile dysfunction. MUSE® (alprostadil), a first generation therapy for the treatment of ED, is already on the market and generating revenue for VIVUS.

Certain statements in this press release are forward-looking within the meaning of the Private Securities Litigation Reform Act of 1995. These statements may be identified by the use of forward-looking words such as “anticipate,” “believe,” “forecast,” “estimated” and “intend,” among others. These forward-looking statements are based on VIVUS’ current expectations and actual results could differ materially. There are a number of factors that could cause actual events to differ materially from those indicated by such forward-looking statements. These factors include, but are not limited to, substantial competition; uncertainties of patent protection and litigation; uncertainties of government or third party payer reimbursement; reliance on sole source suppliers; limited sales and marketing efforts and dependence upon third parties; risks related to the development of innovative products; and risks related to failure to obtain FDA clearances or approvals and noncompliance with FDA regulations. As with any pharmaceutical under development, there are significant risks in the development, regulatory approval and commercialization of new products. There are no guarantees that future clinical studies discussed in this press release will be completed or successful or that any product will receive regulatory approval for any indication or prove to be commercially successful. VIVUS does not undertake an obligation to update or revise any forward-looking statement. Investors should read the risk factors set forth in VIVUS’ Form 10-K for the year ended December 31, 2009 and periodic reports filed with the Securities and Exchange Commission.

By THOMAS GRYTA

A new generation of anti-obesity drugs could hit the market in coming months, the latest attempt in what has proved a difficult medicine to make safe for patients.

Currently, just two anti-obesity drugs are approved for long-term treatment, and medical practitioners say both can cause undesirable side effects in many patients. The three new medications, which have been submitted for approval to the Food and Drug Administration, also can be expected to have side effects for some patients, particularly because treating obesity with drugs involves altering the body’s chemistry. But doctors say different weight-loss medications affect people differently, so having more choices should help them match a patient to a therapy that maximizes weight loss while minimizing side effects.

“Obesity has many causes, and ferreting out what is going to work in individuals requires more options,” said Charles Billington, a professor of medicine at the University of Minnesota and medical director of the obesity program at the Minneapolis VA Medical Center.

The FDA will need to review data on the drugs, and approval isn’t assured. The agency is aware of past problems with anti-obesity drugs and plans to evaluate the new drugs under the assumption that patients likely would use them indefinitely, an FDA spokeswoman said.

The three new drugs awaiting regulatory approval are lorcaserin, manufactured by Arena Pharmaceuticals Inc., Vivus Inc.’s Qnexa, and Orexigen Therapeutics Inc.’s Contrave. The companies are small drug developers and each has held talks to partner with a larger pharmaceutical concern to help sell the products, although no agreements have been signed.

The three drugs work by affecting the patient’s central nervous system to dampen appetite, Dr. Billington said. “To say that you are going to do that without any side effects is just not understanding how things work in real life,” he said.

Typically, medications help moderately obese patients lose about 5% to 10% of their body weight. While not a large percentage, even that much weight loss can mean a big reduction in diabetes and cardiovascular risk, said Jeanine Albu, chief of the Metabolic Clinic at the New York Obesity Research Center at St. Luke’s-Roosevelt Hospital. “The problem is keeping the weight off over time. A lot of people just gradually gain it back,” said Dr. Albu.

Lifestyle Changes First
For most obesity patients, a physician’s first line of treatment is to modify the person’s lifestyle, including through dieting, exercise and counseling. When this isn’t successful, some patients might move on to one of the few anti-obesity drugs currently available. And in cases of dangerous obesity, doctors might recommend bariatric surgery, which makes the stomach smaller. The Centers for Disease Control and Prevention estimates that about two-thirds of U.S. adults are overweight, while a third are considered obese. Obesity is defined as having a body mass index—a measure of weight in relation to height—of 30 or higher.

Some earlier diet drugs have had a mixed history. The so-called fen-phen drug combination manufactured by Wyeth, now owned by Pfizer Inc., was recalled in the 1990s after one of the medication’s components was linked to heart-valve damage.

One drug currently in use also has stirred controversy. Meridia, sold by Abbott Laboratories, was pulled from the market in Europe this year after a study indicated that people with certain health problems who took the prescription drug had more heart attacks, strokes and other cardiovascular problems than people getting a placebo. In the U.S., the FDA required Abbott to put a stronger warning on the Meridia label.

Another drug currently on the market, Orlistat, which is sold over the counter as Alli by GlaxoSmithKline Plc and in prescription form as Xenical by Roche Holding AG, can cause undesirable bowel-related problems in some patients. The drugs haven’t been blockbusters. Financial firm Cowen and Co. estimates that Alli had U.S. sales of $150 million last year, while Meridia and Xenical had sales of $40 million and $35 million, respectively. Doctors also regularly prescribe phentermine, which is approved for short-term use of, say, a few weeks, to treat obesity.

Arena Pharmaceuticals said its lorcaserin drug works by stimulating a neurotransmitter receptor in the brain that helps control appetite and metabolism. The mechanism is similar to the one used by a component of the recalled fen-phen drug combination, but with an important difference.

While the older medications worked on multiple versions of the body’s receptors, including those in the heart, lorcaserin has a very specific target that is mostly in the brain, Arena said. Clinical trials have shown there is no increase in such heart-related side effects with the new drug, it said.

In clinical trials, patients taking lorcaserin lost about 6% of their weight on average, while patients taking a placebo lost between 2% and 3%. The most common side effects of the pill, which would be taken twice a day, were headache and nausea, although both symptoms disappeared after an initial period of use.

Combination Therapies
The two other drugs under FDA review are both combination treatments of compounds that are already on the market, but will be delivered in new dosages and methods. Using two drugs at once can be more effective in treating obesity because the brain has multiple ways of making sure that appetite is preserved, as a survival mechanism. Blocking multiple pathways, therefore, can help ensure that a therapy will work.

Orexigen said its Contrave drug works by stimulating a group of neurons in the brain, known as POMC, which, when activated, seem to result in reduced food intake and increased metabolism. The first drug in the combination, the antidepressant bupropion, turns on POMC. But that action also causes the release of a hormone that subsequently switches POMC back off in order to prevent perpetual weight loss. So the second drug in the combination, addiction-treating naltrexone, blocks that hormone in order to allow weight loss to continue, the company said.

Giving the two together as Contrave, in a sustained-release formulation taken twice a day, led to average weight loss that ranged from 5% to 9.3% of a patient’s body weight in four clinical trials. Trial participants who took a placebo lost between 1.2% and 5.1% of their body weight. The medication’s most common side effects were nausea, constipation and headache, all of which tended to go away after an initial period.

The third drug, Qnexa from Vivus, was the most effective in clinical trials at taking off pounds. In two separate trials, patients lost an average of 10.4% and 11%, respectively, of their body weight, while those taking a placebo lost 1.8% and 1.6%.

Vivus said Qnexa is a controlled-release formulation that combines low doses of the stimulant phentermine, which leads to the release of the stress hormone norepinephrine to cut the body’s appetite, and topiramate, which works in various ways to increase satiety, or the sense of feeling full. Combining the two underlying drugs also seems to counteract some of their individual effects: Topirimate can cause cognitive slowing, which phentermine negates, and topirimate counters the blood-pressure raising of phentermine, the company said.

In clinical trials, the most common side effects of the once-daily Qnexa were constipation and dry mouth, along with mild tingling in the finger tips, all of which eventually went away.

Write to Thomas Gryta((djn, x2169)) at thomas.gryta((djn, x2169)) @wsj.com