New Drug Zaps Fat Cells in Monkeys

An experimental drug helped obese monkeys lose 11 percent of their extra weight in a month, a promising sign in the hunt for obesity drugs that could apply to humans, U.S. researchers said Wednesday.

The drug, known as Adipotide, works by attacking the blood supply of a certain kind of fat, known as white adipose tissue, that tends to accumulate under the skin and around the belly.

Most other obesity drugs focus on either reducing appetite, boosting metabolism or preventing the absorption of fat.

The research, led by the University of Texas MD Anderson Cancer Center, offers a potential new pathway for treatment and has also shown effects in mice who lost 30 percent of their body weight during treatment.

"Most drugs against obesity fail in transition between rodents and primates," said co-senior author Renata Pasqualini, whose study appears in the journal Science Translational Medicine.

"We're greatly encouraged to see substantial weight loss in a primate model of obesity that closely matches the human condition."

The monkeys in the study were spontaneously obese, meaning they overate of their own free will, avoided exercise and therefore had packed on extra pounds.

Their weight declined for the first three weeks of treatment, though a small uptick was seen in the fourth week. The average weight loss during that span of time was 11 percent of their body weight.

The drug designed by the MD Anderson group "binds to a protein on the surface of fat-supporting blood vessels," and contains a "synthetic peptide that triggers cell death," the findings said.

"Their blood supply gone, fat cells are reabsorbed and metabolized."

Clinical trials of the drug on obese men with prostate cancer are planned next, in which human subjects will get daily injections of the drug for 28 days.

"The question is, will their prostate cancer become better if we can reduce their body weight and the associated health risks?" asked co-author Wadih Arap, a professor in MD Anderson's David H. Koch Center for Applied Research of Genitourinary Cancers.

Another promising sign was that monkeys treated with the drug showed an improvement in their resistance to insulin, suggesting it may help ward off the development of type 2 diabetes.

However, it was seen to have some damaging effects to the kidneys, which could be lessened by administering the drug in smaller doses.

The journal noted that Arap, Pasqualini and some other researchers involved in the project own equity positions in two drug-development companies working on the research.

Those positions are "subjected to certain restrictions under institutional policy. MD Anderson manages and monitors the terms of these arrangements in accordance with its conflict-of-interest policy," it said.

Funding for the research came from grants from the National Institutes of Health, the National Cancer Institute and several other foundations.