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Orexigen Hopes to Fatten Up By Entering Multibillion-Dollar Market for Treating Obesity

A local startup believes it holds a key to helping solve the nation’s obesity crisis , a combination of drugs used to treat depression, alcoholism and addiction to such painkillers as opium and heroin.

Orexigen Therapeutics Inc. led a near virtual existence for the past four years, operating with just five employees and a handful of contractors.

At the direction of its venture capitalist-packed board, Orexigen issued no press releases. The firm, said Chief Executive Officer Gary Tollefson, wanted to make sure the drug worked before touting it.

San Diego’s Domain Associates LLC and the Bay Area’s Kleiner Perkins Caufield & Byers, Montreux Equity Partners and Scale Venture Partners are investors.

In an age where biotech companies are going public well before they have a late-stage product, Orexigen played it safe. But now the business has emerged from the shadows to compete for a chunk of the $2 billion to $5 billion market for treating obesity.

The company leased office space in December in Del Mar, completed an initial public offering in May and began the second part of the last phase of clinical trials for Contrave, its obesity drug candidate.

Contrave has so far proven safe and effective, with side effects mostly relating to nausea.

Studies have found that weight loss, as a percentage of body weight, was around 7 percent after 24 weeks on the drug , far greater than the 5 percent per year guideline required for Food and Drug Administration approval.

Tollefson, who spent 13 years at Eli Lilly & Co., said Contrave’s chances of getting an FDA approval are high because the pill is a combination of two drugs that have been on the market for three decades.

Naltrexone is used to treat certain painkiller addictions and alcoholism. Buproprion is prescribed for depression.

The ingredients in Fen Phen, a diet drug combination removed from the market in the late 1990s after it was linked to heart valve damage, were also on the market for 20 years, said Leland Gershell, an analyst with Cowen & Co. in New York.

But the FDA never approved the use of flenfluramine and phentermine together. Rather, doctors began prescribing the combination off-label to treat obesity.

With more than 64 percent of adults in America overweight , 35 percent in California , the market is wide open, experts say.

Just two FDA-approved drugs are on the market for obesity, including Roche’s Xenical, associated with gas and oily bowel discharge, and Abbott Laboratories’ Meridia, which can cause hypertension. Together, they earn about $500 million worldwide.

“There is a lack of a safe and effective drug on the market,” said Shiv Kapoor, a San Francisco-based analyst at Montgomery & Co.

Kapoor, who follows Arena Pharmaceuticals Inc., which also has an obesity drug candidate in the pipeline, said Contrave’s dual-drug nature could hinder rather than speed approval.

“They will have to show which side effects and efficacy are coming from each component,” Kapoor said.

He also raised questions about how insurers would pay for treatment since the two drugs have already been approved.

“Why would patients not just have doctors prescribe the two drugs instead of (Contrave) if they are cheaper?” he asked.

However, Kapoor said he believes it will eventually be a two-drug combination that is most successful in the marketplace , just not necessarily two that are already approved.

It is the dual action of Contrave, said Tollefson, which has allowed patients to not only lose the weight, but keep it off.

While Bupropion initiates the weight loss by triggering the brain to release an appetite-inhibiting hormone, Naltrexone blocks endorphins from slowing down the release of that hormone, thereby allowing further weight loss.

“To have a lasting and promising effect, you have to attack (obesity) from a variety of angles,” Kapoor said.

Potential solutions are coming from all sides from the research labs of San Diego’s biotech industry.

Amylin Pharmaceuticals Inc., which already has two approved diabetes drugs, is testing five combinations of naturally occurring peptide hormones.

Its most advanced candidate, Pramlintide, is in the last stages of a phase-two clinical study. Drugs must pass three phases before seeking approval from the FDA.

Arena’s Lorcaserin works by stimulating a serotonin receptor in the brain, which helps regulate appetite and metabolism.

“These hormones physiologically tell the brain when to stop eating,” said Christian Weyer, Amylin’s director of clinical research.

An FDA committee is expected to meet this week to discuss the safety of remonabant, also known as Acomplia or Zimulti, for which French pharmaceutical giant Sanofi-Aventis is seeking FDA approval. The United Kingdom approved the drug last year.

A handful of other companies have obesity drugs in advanced stage clinical trials, including Regeneron Pharmaceuticals Inc.’s Axokine, known for causing nausea and dry coughing.

Illinois firm Takeda’s Cetilistat began the last stage of clinical trials in early 2006 in Japan. The drug has not been associated with serious side effects.

Pfizer’s CP945598 is another serious competitor, but likely won’t reach the market until 2009, according to IMS Health, a Fairfield, Conn.-based financial forecasting company.

Orexigen and Arena say they both plan to seek approvals in 2009. Weyer said it is too soon to tell when Amylin would file for approval.

Orexigen’s stock trades on the Nasdaq around $18, while Arena and Amylin shares trade on the same exchange around $13 and $42, respectively.


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