ANOTHER SHOT AT ENDING HIV; NEW VACCINE OFFERS MOST HOPE YET FOR HALTING SPREAD OF VIRUS.

Byline: Carol Bidwell Daily News Staff Writer

When Pat Duffy, a gay, 48-year-old communications worker, heard that the first Phase III tests for a potentially AIDS-preventing vaccine were under way, his first thought was: Hallelujah!

``I feel good about it and would certainly, if it were offered, stick my arm out and have them pump me full of it,'' he said. ``It looks so wonderful that they've got something that might work against this insidious disease.''

But Duffy - like most AIDS health-care professionals and scientists - doesn't see AIDSvax, a vaccine that has produced HIV antibodies in 99.5 percent of 1,200 test subjects so far, as the ultimate answer to the pandemic that so far has claimed nearly 12 million lives worldwide. Health experts say another 30 million are infected with HIV, the AIDS-causing virus.

``I think everybody is cautiously optimistic whenever there's a new development, whether it's a new drug, a new treatment or whatever - and rightfully so,'' said Corri Planck, spokeswoman for the Los Angeles Gay & Lesbian Center. ``The drugs (developed so far for AIDS treatment) haven't worked for everyone. And they're very expensive. This could be the same.''

Wil Strain, a treatment advocate for AIDS Project Los Angeles, agreed. ``I think it's far too soon to tell how well (AIDSvax) will work,'' he said. ``Vaccines have been in development for many years, and there has been a lot of skepticism.''

Leader of the pack

Some 25 potential HIV vaccines have been tested worldwide, but this one - developed by the South San Francisco-based VaxGen Inc. - is the first to reach this level of testing. Phase III testing is the final step before the U.S. Food and Drug Administration will consider approving a drug for medical use.

VaxGen kicked off its testing last week in Philadelphia. The firm will test the vaccine over the next three years in at least 30 sites - including Los Angeles and San Francisco - on 5,000 volunteers who are considered to be at high risk of contracting the AIDS virus, such as gay men and women whose sexual partners are infected. Two-thirds of the volunteers will receive AIDSvax, and the other one-third will receive a placebo.

Volunteers will receive injections every six months for 30 months, with a six-month follow-up period.

Vaccines are being administered at clinics specially set up for testing throughout the United States. Because of FDA rules and security worries, VaxGen will not say where the clinics are located. The vaccine is not available at AIDS Project L.A., the Gay & Lesbian Center or at UCLA, sites where AIDS counseling and other services are offered.

People who want to volunteer to be a part of the trials can call VaxGen at [phone] or access its Web site at: www.vaxgen.com.

VaxGen has trumpeted its vaccine as the first medication that can prevent HIV infection. But what makes it different from other vaccines that have been developed - and have failed? What makes some scientists think AIDSvax may be at least a partial antidote to the spread of HIV?

Like other vaccines, AIDSvax is designed to train the human body's immune system by creating antibodies to protect itself against HIV infection. The vaccine uses a genetically engineered protein from the surface of the virus, rather than the naturally occuring virus, which scientists say should allay fears that instead of preventing HIV infection, the vaccine could actually cause it in test subjects.

Injecting the recombinant protein stimulates production of antibodies that attack any invading HIV, preventing the virus from binding to and infecting healthy T-cells, immune-system cells that fight infections.

New and improved

Many U.S. scientists are skeptical about AIDSvax because it is based on gp120, a vaccine the National Institutes of Health decided in 1994 was too weak to study further. But Daniel T. Reiner, chief operating officer of VaxGen, said AIDSvax is a substantial improvement on gp120.

The first tests of AIDSvax began in 1990; chimpanzees inoculated with the vaccine - and later with HIV - still show no sign of infection, said company spokeswoman Donna Walters. More than 1,200 humans have received the vaccine, and it has prevented HIV infection in nearly all of them.

The only side effect has been a temporary sore spot on the arm where the vaccine is injected, as with many vaccines.

``We're very optimistic,'' she said. ``We've passed every hurdle so far.''

If the vaccine does prevent HIV infection, it could mean a lot to Los Angeles residents, as well as people all over the world, said Chuck Henry, director of the Los Angeles County Office of AIDS Prevention and Policies. In the 17 years since the AIDS virus was first isolated and tracked, 24,361 Los Angeles County residents - men, women and children - have died of the disease. About 12,500 people are living with full-blown AIDS, about 11,500 have tested HIV-positive, and another 16,000 or so are believed to be infected but have not yet been diagnosed, he said.

``There's a lot to do from the prevention standpoint,'' Henry said.

The wheels of science

Whatever the results of the AIDSvax trials, they will be a success in the eyes of scientists because they will help fill in the blanks as progress is made toward a prevention vaccine, say medical experts.

``We ... need to go ahead with wide-scale testing and be willing to fail,'' Dr. Richard Marlink, executive director of the Harvard AIDS Institute, said in a 1997 statement. ``We're not going to succeed if we're not willing to fail.''

Dr. Ronald T. Mitsuyasu, director of the UCLA AIDS Care Center, echoed that belief.

``I don't think this vaccine will prevent AIDS,'' he said. ``It may diminish it, reduce the proportion of people who will get the infection, though, and that's good. But there will still be the question of how to identify those it will help. No matter what the results of the testing, it will obviously raise more questions, which is natural for scientists.

``But research is never a waste. Whatever we learn from this study ... will advance the course of science. I think it will be a next step in the development of other vaccines. And one of them may prevent AIDS. I would hope to see such a vaccine within 10 years.''

It's a small step toward the solution, but one many also fear will send the wrong message. If science does come up with a vaccine that can prevent HIV infection, in as little as three to 10 years, does that mean a return to the sexual free-for-all of the late 1960s and early '70s?

Duffy, who admits to having indulged in ``wild and indiscriminate'' sex with strangers in his late 20s and early 30s, said he hopes not.

``I'm just really concerned that this vaccine is going to give everybody a false sense of security,'' he said. ``Even if they could give me something to prevent AIDS, I wouldn't slut around anymore. I'm older and wiser and monogamous, and I know there are other diseases out there you can get. Until they can actually track people and make sure it works, we're going to have to be vigilant and responsible. This vaccine may be a great thing, but it's not a license to go back and not practice safe processes.''

CAPTION(S):

3 Photos

Photo: (1--Cover--Color) Test trials of new AIDS vaccine raising hope, skepticism

Myung J. Chun/Daily News

(2) A man takes a saliva test for HIV at the Los Angeles Gay & Lesbian Center, where a cautious optimism prevails over news of a potential vaccine against the virus that causes AIDS, a spokeswoman says.

(3) Los Angeles Gay & Lesbian Center counselor Oscar Marquez gives a walk-in client a risk assessment, part of the HIV-test regimen.

John Lazar/Special to the Daily News