Assistant Managing Editor

Investors - and prospective partners - hoping that detailed data emerging from this year's Obesity Society meeting in Washington might shed more light on the three frontrunners in the weight loss drug race came away with some more promising data on each but no clear winner.

In fact, the sheer quantity of efficacy and safety results presented over the weekend at the annual meeting of The Obesity Society in Washington likely will take time to wade through.

That "large bolus of data may be overwhelming for some physicians to quickly absorb," analyst Elemer Piros, of Rodman & Renshaw, wrote in a research note.

Those doctors, he added, "will ultimately determine their drug of choice based on personal experience," though average weight loss data are sure to remain "one of the key selling messages."

In terms of weight loss data, the combination drugs generally have prevailed. Previously reported top-line figures put placebo-adjusted weight loss numbers as high as 9.4 percent and 8.6 percent in two Phase III trials of Vivus Inc.'s Qnexa (phentermine/topiramate), while Orexigen Therapeutics Inc.'s Contrave (bupropion SR/naltrexone SR) came in at 4.2 percent to 5.2 percent.

Arena Pharmaceuticals Inc.'s lorcaserin, a 5-HT2c serotonin receptor agonist, came in at the lower end, with a 3.6 percent placebo-adjusted weight loss in its first Phase III study. But lorcaserin's clean safety data could give it a foothold in the market.

Piper Jaffray analyst Edward Tenthoff called safety "a key factor" for FDA approval and partnering potential. And lorcaserin "appears to be the safest of these three agents with side effects not meaningfully different than placebo," he wrote in a research note.

But as yet, none of the three products has managed to snag a partnership. San Diego-based Arena has said it is actively seeking a big pharma partner to reach the broad primary care space.

Orexigen, also of San Diego, intends to build its own sales force to reach the specialty market while looking for a larger collaborator for the primary care space and ex-U.S. territories, and Mountain View, Calif.-based Vivus entered partnering mode after reporting the last of its Phase III trials earlier this year.

Industry experts had been expecting data from the obesity meeting to help gauge big pharma interest.

Overall, results presented at the conference offered no big surprises. As JMP Securities analyst Jason N. Butler noted, none of the data "will move the needle dramatically in terms of our approval and commercial potential."

But they could help to differentiate each product's marketing profile if all three reach the market, as many analysts predict.

Data on Vivus' Qnexa showed that the drug's effect was consistent across all levels of body mass index in the EQUIP trial, which tested low-dose and full-dose versions in 1,267 morbidly obese patients. And a measure of excess body weight loss was 42 percent in the intent-to-treat population of the CONQUER study, which enrolled 2,487 overweight and obese patients with high blood pressure, high cholesterol or Type II diabetes.

Excess body weight loss (EBWL) data, while not specifically among the FDA requirements for obesity drugs, were highlighted by each company at the annual conference.

In two Phase III trials, Orexigen's Contrave demonstrated an EBWL of 30 percent and 31.7 percent vs. placebo rates of 6.7 percent and 4.7 percent.

The product also produced significant improvements in markers for cardiometabolic risk and reduced HbA1c levels in patients with Type II diabetes who began the trial with an HbA1c level greater than 8 percent.

Additionally, Contrave patients reported an increased ability to control their eating and resist food cravings.

New data from Arena's BLOOM study, which barely met its endpoints earlier this year, showed that patients on lorcaserin who completed the trial according to protocol lost 31 percent of their excess weight compared to 12 percent in the placebo group. (See BioWorld Today, March 31, 2009.)

And tolerability data was consistent with results previously reported, with no increase in depression or suicidal ideation compared to placebo. Though two suicide attempts were reported in the trial, those events were not believed to be related to the drug.

Shares of Arena (NASDAQ:ARNA) gained 17 cents Monday to close at $4.51, while shares of Orexigen (NASDAQ:OREX) lost 2 cents to close at $7.63 and Vivus' stock (NASDAQ:VVUS) rose 62 cents to close at $9.80.

In other conference news:

• Halsa Pharmaceuticals Inc., of Houston, reported preclinical results demonstrating that recombinant human Zinc-alpha2-glycoprotein induced progressive loss of body weight in mice of 3.5 g in five days, together with a rise in temperature of 0.4 degrees Celsius, suggesting an increase in energy expenditure. In addition, ZAG produced a normalization of the diabetic glucose tolerance curve after three days of treatment.

Published  October 27, 2009