Washington Editor

Shares of BioSante Pharmaceuticals Inc., which is developing a female sexual dysfunction product, plunged by more than a third on Friday in the wake of a negative FDA panel review of a related product.

Lincolnshire, Ill.-based BioSante acknowledged that upcoming Phase III studies of LibiGel, a once-daily transdermal testosterone gel, could be delayed in order to await agency feedback on trial protocol changes. Its stock (AMEX:BPA) dropped $2.66 Friday, or 35.5 percent, to close at $4.84.

A day earlier, the FDA's advisory committee for reproductive health drugs voted not to recommend approval of the Intrinsa testosterone patch, which is in development by Procter & Gamble Co. for female sexual dysfunction in surgically menopausal women. The panel said the Cincinnati-based company's data proved the product's efficacy, but the committee wanted more safety information on testosterone's effects on patients with cardiovascular risk and breast cancer. There were no issues with safety in patients who have been studied with Intrinsa to date.

The agency, of course, has come under recent fire over allegations of drug safety oversights concerning Vioxx, made by Merck & Co. Inc. The FDA, which ultimately decides a product's fate, typically follows the advice of its panels.

"We're hoping that this does not delay the trials too much," Stephen Simes, BioSante's president and CEO, told BioWorld Today. "The good news is that we have not begun our trials, so it's not as if we have to stop and restart. We're in the midst of preparing our Phase III protocols, so we hope that now that the FDA has the benefit of the advisory committee's wish list, as I call it, the FDA will give an opinion finally on what it is they want. And we'll integrate that into the trials."

He noted that at this time, the company expects only a three-month delay. As a result, it would start its pivotal program near the end of the second quarter, rather than the end of the first.

Simes added that to date, no studies of LibiGel have indicated a safety risk in patients with cardiovascular risk or breast cancer.

"There is no difference in any parameter from placebo," he said. "Specifically, to lipid levels and HDLs, there is no difference from active to placebo, as was shown in the P&G trial. This had nothing to do with the data presented to the FDA. This is speculation by the panel on what could be, and that's the frustrating part of this."

In any case, because P&G's program has been set back, BioSante could potentially launch LibiGel into the market shortly after Intrinsa.

"[Procter & Gamble was] going to have a two or two-and-a-half-year lead over us," Simes said. "The good part about that was that they would create a multibillion-dollar market, and we could go in and take 10 or 20 percent. Now they'll probably have a year lead over us, during which time we hope they create a multibillion-dollar market, and we'll go in and take 10 or 20 percent. Some people had been concerned that maybe their lead was too long, and we'd have more difficulty getting into the market, but now that lead is cut down."

Outside of LibiGel, he noted that the company's nearest-term product opportunity remains Bio-E-Gel (estradiol gel), which is being developed as a once-daily transdermal gel for treating symptoms of menopause such as hot flashes. A pivotal study is nearing completion, and BioSante expects to file its new drug application by the middle of next year.

Also, the company is developing calcium phosphate nanoparticles as drug delivery vehicles and for enhancing the effects of vaccines.