Titolo: 20:10 WSJ: Drug Slims Down Obese Monkeys By Killing Fat Cells
Testo: By Ron Winslow
Of THE WALL STREET JOURNAL
In a study that provides provocative support for a new approach to treating obesity, a drug that kills a particular type of fat cell by choking off its blood supply was shown to cause significant weight loss in obese monkeys.
After four weeks of treatment at M.D. Anderson Cancer Center in Houston, obese monkeys given daily injections of the drug, called adipotide, lost an average of 11% of their body weight. They also had substantial reductions in waist circumference and body-mass index and, importantly, striking improvement in the ability to respond to insulin, researchers said. The drug didn''t have any effect on weight when given to lean monkeys.
(This story and related background material will be available on The Wall Street Journal website, WSJ.com.)
Results of the study, published online Wednesday by the journal Science Translational Medicine, confirmed a 2004 report from the same research team showing marked weight loss in mice treated with the agent.
But success in mice studies often fails to translate to people. Because the biology of monkeys is much closer to that of humans, researchers said the new findings offer hope that the treatment could prove effective in people.
Indeed, as a result of the new findings, the first human trial, which would involve obese patients with advanced prostate cancer, could begin as soon as early next year. Rights to the drug, which was developed at M.D. Anderson, have been licensed toAblaris Therapeutics Inc., a unit of Arrowhead Research Corp. (ARWR) in Pasadena, Calif., that was formed last year. Plans to develop it for broader uses will depend, among other things, on finding a safe and effective dose in the initial tests.
Most weight-loss drugs aim to suppress appetite or amp up the body''s metabolism to trigger burning of more calories. But systems governing those processes are especially complex, and several drugs have failed to clear regulatory hurdles because of modest benefits and troublesome side effects.
Starving fat cells of their blood supply would be a distinctly different strategy, one that experts say might circumvent some of the side effects that have hampered other efforts.
"This is really new stuff," said Randy J. Seeley, director of the Cincinnati diabetes and obesity center at University of Cincinnati, who wasn''t involved in the current study. "There''s no way to know if this will become a therapy or not, but at least it opens up a new way to think about therapies, and we have not had a lot of those."
There were kidney side effects, but researchers said they resolved quickly when the treatment was stopped. Monkeys in the study were treated for just four weeks, and what impact kidney or other side effects might have with long-term use isn''t known. That is one of the challenges facing efforts to get the drug on the market.
Blocking or undermining the formation of blood vessels is called anti-angiogenesis. It is the key mechanism by which Roche Holding AG''s (RHHBY, ROG.VX) drug Avastin works against certain cancers.
Research by Wadih Arap, his wife, Renata Pasqualini, and their laboratory at M.D. Anderson have determined that cells in specific organs in the body-- including those on blood vessels that nourish white fat cells--have distinct molecular markers on their surfaces they liken to ZIP codes.
One part of adipotide is designed to home in specifically on the zip code specific to the white-fat-cell blood vessels. The other part is a therapeutic payload that kills the cells.
The new study was funded by the National Institutes of Health and various philanthropic foundations. The findings, Dr. Pasqualini said, indicate adipotide "looks like a promising lead in a situation where there is very little out there that''s in the pipeline" for obesity.
James Hulvat, head of research and development for Ablaris Therapeutics, said the decision to test the agent first in obese prostate-cancer patients reflected in part the interests of M.D. Anderson, which is paying for the initial study, and the agent''s potential for demonstrating an important benefit in a limited group of patients. White fat cells secrete hormones that are known to promote the growth of prostate tumors.
"We''ll carry the drug forward into a broader weight-loss indication if the [initial] clinical trial data support that," he said. The company is also interested in pursuing the agent as a potential treatment for type 2 diabetes, which is associated with obesity.
Dr. Pasqualini and Dr. Arap are entitled to royalties that could result from successful commercialization of the drug. Both researchers and M.D. Anderson are investors in Ablaris Therapeutics.