By Jim Shrine

Agouron Pharmaceuticals Inc. presented Phase I data on its HIVprotease inhibitor Monday and is preparing to start a small Phase IIstudy that, with satisfactory results, would trigger a $24 millionmilestone.

Results of the Phase I studies were presented at the Second NationalConference on Human Retroviruses and Related Infections, beingheld in Washington.

Agouron, of La Jolla, Calif., said moderate oral doses of thecompound, AG1343, resulted in sustained levels of the drug inhuman plasma that exceeded those necessary (in preclinicalexperiments) to inhibit replication of HIV.

"We are very encouraged by the exceptional pharmacokinetic profiledemonstrated by AG1343," Donna Nichols, Agouron's director,corporate communications, told BioWorld. "But we also recognizethat demonstration of its anti-HIV activity in infected individualswill be critical to establishing AG1343 as an important therapeuticproduct. We will be addressing this issue in the new few months."

She was referring to a 28-day pilot Phase II study that Agouronexpects to start in early March. The study, being conducted in theU.K., should be completed by the end of April, Nichols said.

"We're going to do a pilot Phase II study in 25 HIV-positiveindividuals to confirm the pharmacokinetics we saw in healthyvolunteers in Phase I, and to look at surrogate signs of efficacy [viralload, CD4 counts]" Nichols said.

"Satisfactory" results from the pilot study would trigger a $24million payment to Agouron from Japan Tobacco Inc., of Tokyo,which already has paid Agouron $6 million related to the AG1343collaboration. Under an earlier arrangement, the companies areworking on anti-viral programs targeting rhinoviruses, herpes virusesand hepatitis C. The collaborators said they now will focus allresources, including more Japan Tobacco scientists, to the anti-viralefforts.

As for AG1343, Agouron and Japan Tobacco will share developmentcosts after the pilot Phase II study. But Agouron won't have to paymore than $15 million toward it's co-development responsibility.Any difference would be paid back after commercialization.

Agouron has exclusive rights to AG1343 in North America, JapanTobacco has rights in Asia and a joint venture of the companies willhold rights to the rest of the world.

Agouron's stock (NASDAQ:AGPH) closed at $15.50 per shareMonday, down 50 cents.

In Other Conference News

* Preclinical data was presented showing VX-478, beingdeveloped by Vertex Pharmaceuticals Inc., of Cambridge, Mass., andBurroughs Wellcome Co., of Research Triangle Park, N.C., an HIVprotease inhibitor, had potent anti-HIV activity in vitro, was welltolerated, was synergistic with Wellcome's AZT, and warrantsfurther study.

* A study conducted at the University of Pittsburgh MedicalCenter in collaboration with Therion Biologics Corp., of Cambridge,Mass., showed that long-term HIV-infected people who had notprogressed to AIDS had low levels of the virus and high levels ofspecialized "memory" killer T cells that specifically recognize partsof HIV. For AIDS vaccines to be effective, they need to stimulatememory killer T cells, investigators said. n