Human Tests Planned for Anti-Obesity Drug

Amgen Inc.’s much-publicized anti-obesity drug will be tested on humans this summer for the first time.

The Thousand Oaks-based biotechnology giant is working out final details with the Food and Drug Administration and with various obesity centers in North America that will probably test the drug--called leptin--on 50 to 100 volunteers, Amgen spokesman David Kaye said Friday.

When new drugs are tested on humans, it typically takes two to three test stages--and strong results--before a company can apply to the FDA for approval to sell the drug. The first phase tests the drug for safety, and that could take from several months to a year, Kaye said.

Amgen has invested heavily in leptin, a developmental drug that is a gene-spliced copy of a protein that the company hopes is a key regulator of body fat. It licensed the drug more than a year ago for $20 million from Rockefeller University in New York.

In lab tests, leptin knocked off between 22% and 40% of the weight of obese mice within weeks.

But Wall Street’s enthusiasm for the drug has dimmed considerably since then. In February, a New England Journal of Medicine study found that obese people already have up to four times the normal level of leptin.

And last winter, drug rival Hoffman-La Roche Inc., in collaboration with tiny Millenium Pharmaceuticals in Cambridge, Mass., isolated the gene for the brain’s receptor for leptin. Analysts now think the receptor might be a key to fighting obesity, rather than leptin.

“Despite Amgen’s optimism, I continue to be skeptical about the use of leptin,” said Jim McCamant, editor of the Medical Technology Stock Letter in Berkeley. Giving obese people “extra leptin may make the disease get worse.”

But Amgen’s scientists still believe that giving obese people leptin in a drug form will “cause the trigger to go off in the metabolism so you just don’t want to eat anymore,” Kaye said.

The name leptin comes from a Greek word meaning thin. As more fat enters the body, more leptin is sent into the blood stream, until it signals the brain that the stomach is full.

As for whether leptin actually works, “we’ll know when we put it in humans,” Kaye said.

Hoffman-La Roche still faces elaborate lab research to come up with its own new anti-obesity drug, which it must then try on animals before moving into human tests. That process could take another two years, McCamant said.

Aside from the medical unknowns of whether these drugs will work, there is also a longer-term marketing issue.

Amgen’s leptin must be given by injection. But Hoffman-La Roche’s goal from the start has been to come up with a drug in pill form.

“That would have a tremendous marketing advantage over any other drug,” said Paul Burn, Hoffman-La Roche’s director of metabolic diseases.

On Friday, Amgen’s stock closed at $52.375 on Nasdaq, down $1.125.