Analysis: Merck's obesity drug scrapped

By STEVE MITCHELL, UPI Senior Medical Correspondent

WASHINGTON, Oct. 3 (UPI) -- Merck's anti-obesity treatment candidate MK-0577 failed to induce significant weight loss in a clinical trial released Tuesday, but the company appears to be moving ahead with another compound.

Merck hasn't said much publicly about MK-0577, which blocks a receptor for neuropeptide Y. The drug showed promise in animal studies and a phase 1 study, but failed in a phase 2 study involving about 1,600 patients that was published in the October issue of Cell Metabolism.


"It's (MK-0577) certainly on hold," Steven Heymsfield, an author of the study and a researcher with Merck, told United Press International. "Merck, at the moment, has now plans to pursue it for monotherapy."

The company could revive MK-0577 in the future as a combination therapy with another drug, but there aren't any plans in the works to do that, Heymsfield said.

Other anti-obesity compounds in development include MK-0364, he said. Merck hasn't revealed yet what the compound is, but it's currently in a phase 2 trial, he added.

In the phase 1 proof-of-concept study for MK-0577, the drug was well tolerated and induced a modest weight loss in obese individuals who took it for 12 weeks.


The results spurred Merck to initiate a yearlong phase 2 study involving more than 1,600 patients who received placebo or MK-0557. The placebo group lost an average of 4 pounds compared to 7.5 pounds in the MK-0557 group. The difference was statistically significant, but it was not enough to support using the compound as a treatment for obesity, Heymsfield said.

Merck had kept the 0577 program pretty quiet. Anthony Butler, an analyst with Lehman Brothers, told UPI he had never heard of MK-0577.

"Neither we nor the street know anything about it," Butler said.

Over the next 12 months Butler said he expects Merck to do well and emerge relatively unscathed from the Vioxx fiasco.

The company has launched three new vaccines this year, including Gardasil, and its type 2 diabetes drug Januvia could receive Food and Drug Administration approval later this month, he said. In addition, Zolinza is expected to be approved later this year for treatment of lymphoma and the company could file for FDA approval of MK-0518, an integrase inhibitor for HIV infection, by the end of the year, followed by a couple of other products next year.

Merck "should do pretty well," Butler said. The question is how well they will execute their plans and whether their new products will replace the void left by the expiration of patents for Zocor and Fosamax.


Butler said he expects the new products to make up the slack, but "the question is really by how much," he said.

In terms of the Vioxx lawsuits, Butler noted that he's attended seven of the trials and the decisions depend on the composition of the jury and the plaintiff attorney.

"The key is not the number of cases ... the key is avoiding a class action suit," he said. So far, Merck has done that, choosing instead to fight each case individually.

"I think they're going to survive it quite fine," Butler said.

Another drug in Merck's pipeline that is showing promise is its new COX-2 inhibitor Arcoxia. Preliminary data indicated the compound has a similar rate of cardiovascular events as the non-steroidal anti-inflammatory drug diclofenac.

Bank of America analyst Chris Schott stated in a recent research report the findings increase the chances of Arcoxia gaining approval in the United States.

In addition, Schott raised his sales projections for Arcoxia by $40 million in 2007. By 2010 he estimates the drug will have worldwide sales of $425 million. These projections do not assume U.S. sales.

Other big players in the obesity market include sanofi aventis' Acomplia, which was approved in Europe, and received an "approvable" letter from the FDA in February.


Sanford Bernstein analyst Gbola Amusa said in a research report issued Tuesday that winning a U.S. approval for Acomplia could be key to sanofi's efforts to gain back investor confidence.

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