Orexigen Obesity Drug Hits Weight Loss Goal in Studies, Company Looks Toward FDA
San Diego-based Orexigen Therapeutics dumped a boatload of information in the public domain this morning about clinical trials of its experimental obesity drug. Investors have been in a wait-and-see mode about this drug for months after arguing over the merits of one big trial, but they reacted positively to this new batch of data, sending the stock up 16 percent to $6.62 just after the opening bell.
Orexigen (NASDAQ: OREX) said today that all three of the big clinical trials of the drug in obese patients reached their goals in showing that the treatment helped people lose more weight than a placebo. The company also said that it found encouraging signs on secondary goals, like reducing cholesterol, and blood sugar levels, and helping patients develop slimmer waists. There wasn’t much in the initial announcement about side effects, although Orexigen said nausea was the most common side effect that caused patients to drop out of the studies, and that seven out of 4,500 patients in the trials had severe side effects that may have been related to the drug, including gallbladder inflammation, seizure, heart palpitations, and vertigo.
The drug, a longer-lasting form of two generic treatments known as buproprion and naltrexone, has now cleared enough hurdles that Orexigen plans to send off an application to the FDA in the first half of 2010 to start marketing it in the U.S. as Contrave. If the FDA agrees the drug is safe enough to reach the market, then it has a shot to tap into a market surely worth multi-billions in the U.S. Obesity rates in the U.S. have been skyrocketing for years, as a result of the deadly combo of the sedentary lifestyle and junk-food culture. About two-thirds of U.S. adults are now considered overweight or obese, putting them at risk for a litany of conditions such as heart disease, diabetes, high blood pressure, and arthritis. The cost to society of all this unhealthy weight gain is hard to measure because it’s intertwined with so many diseases, but a U.S. Surgeon General’s report in 2000 fingered it as responsible for about 9 percent of national healthcare spending.
“The results demonstrate the potential for Contrave to help patients in their battle against obesity,” said Mike Narachi, president and CEO of Orexigen, in a statement.
Before breathless commentators start turning too many cartwheels though, it’s worth a closer look at the data to see what kind of magnitude of weight loss researchers saw with Orexigen’s drug.
The FDA has given guidance to drugmakers that it typically likes to see a new obesity drug cross at least one of two thresholds to win an approval: patients on the treatment have to show at least 5 percentage points of body weight loss improvement over a placebo group, or at least twice as many patients on the drug have to lose 5 or 10 percent of their total body weight compared to those on a placebo. It almost goes without saying that for a condition that millions of people have, and that doesn’t imminently threaten them with death, the safety profile of such a drug had better be squeaky-clean.
So how did Orexigen do? About half of the patients in two big trials (48 percent and 56 percent) lost at least 5 percent of their body weight on the Orexigen treatment after little more than a year, which is about three times as many people who did that well in the placebo group (16 percent and 17 percent, respectively.) So far, so good.
Here’s where things get into a little more of a gray zone. The average patient taking the drug in the first trial, COR-1, lost 6.1 percent of his or her body weight, compared with 1.3 percent for those on placebo. The second trial known as COR-2 showed a similar effect, with 6.4 percent average body weight on the Orexigen drug, compared with 1.2 percent in the placebo group. If these trials are pooled together, that means the average patient had exactly 5 percentage points of more weight loss than placebo—the minimum of benefit the FDA wants to see on that important measurement.
The full details of these studies—including a more detailed picture of risk and benefit that the FDA will get to see—will be further analyzed and submitted at scientific conferences and peer-reviewed journals, the company said. The company, as we have written before, will have to compete for market share for this drug with two other companies in the final stages of developing obesity drugs—San Diego-based Arena Pharmaceuticals (NASDAQ: ARNA) and Mountain View, CA-based Vivus (NASDAQ: VVUS). This battle to create the next big thing for obesity is going to be a story to watch for the next couple years.