Miami Herald - September 25, 2009
Fred Tasker, ftasker@MiamiHerald.com

While the Thai experiment is the first to prevent infection by the HIV virus that creates AIDS, Dr. Margaret Fischl of UM is working on a vaccine that would be given to patients already infected with HIV to help boost their immune systems to fight off the disease. Both vaccines are years away.

If successful, the Fischl vaccine could replace the two- and three-drug "cocktails" of antiretroviral drugs now used to improve and prolong the lives of people with HIV. That approach is expensive and also produces numerous side effects.

Fischl is one of the world's most respected AIDS researchers. In 1987, she was instrumental in developing AZT, a breakthrough that provided the first effective antiviral medicine that stopped AIDS from killing nearly all of its victims. It is still in use today along with many newer drugs, and AIDS deaths have plummetted.

Her new vaccine, being developed in conjunction with a major out-of-state biotech firm, has been successful in treating HIV in small mammals up to the size of rhesus monkeys. It should be ready for human trials by about January, she said.

"The goal is to use the vaccine as the mainstay of treatment, so infected people would no longer need HAART (highly active antiretroviral therapy), with its expense and side effects," Fischl said. "With this, they would take a shot every year to boost their systems and keep them in shape."

ENCOURAGING NEWS

Alan Bernstein, executive director of the New York-based Global HIV Vaccine Enterprise, which is not involved in Fischl's study, called news of Fischl's vaccine trial "great news for people who already have HIV."

"Obviously, the vaccine in the Thai trial would not help people who already have HIV" because it's given to uninfected people to prevent HIV, he said. "So this vaccine would be very complementary."

Also, he said, people who control HIV with antiretroviral drugs are never cured and must stay on the drugs for life. And he said new research suggests that such people are developing signs of premature aging, such as arthritis and early dementia.

Since a therapeutic vaccine would be aimed more directly at the HIV virus, it might have fewer toxic side effects, he said. It, too, would not be a cure.

Fischl and the biotech firm, which she cannot yet name, have been working on the new vaccine for years. She said more details will be released soon. It has been successful "in vitro" in the lab and has worked well in trials with six rhesus monkeys who had been infected with the HIV virus, she said.

"We know the vaccine works all the way up to the monkey model. We know its safety profile already," Fischl said. By about January, she said, it should be ready for its first trials in humans. About 30 volunteers would be recruited at several universities.

TREATING HUMANS

Human trials are very sensitive, she said.

"I feel very strongly that when you do a study in humans, even if you have volunteers lined up around the block, you move slowly. You give a dose to the first patient, and you wait to make sure there are no side effects. Then you give it to the second patient."

Eventually, the vaccine would be given to humans with HIV who then would go off their antiretroviral medicines. They would be watched carefully to see if any had "breakthroughs" of the HIV virus.

If all goes well, the new vaccine could seek "fast-track" approval by the FDA and be on the market in three years, she said.

Fischl praised the breakthrough in Thailand. She said she favors bringing it to U.S. markets, even though it protected only 31 percent of Thai subjects who took it.

"It this were a flu vaccine, it would be stopped cold because the success rate is so low," she said. Vaccines against H1N1 swine flu and regular seasonal flu report success at more than 85 percent.

In the Thai trials, new HIV infections occurred in 51 of the 8,197 given the vaccine and in 74 of the 8,198 who received dummy shots -- a 31 percent reduction in the number of new infections.

It's not a very big difference, Fischl said, "but you could argue that since this epidemic is moving so quickly, you might want to bring it to market. I guess anything at this point that can stop the spread of HIV is important."

The Thai vaccine was tested against local strains of HIV, leading some scientists to wonder if it would work against U.S. strains of HIV. But Fischl said U.S. strains are similar enough that that should not be an issue.

Around the world, at least 15 AIDS vaccine trials are under way at various stages, with more than 8,500 volunteer subjects in the United States, Brazil, South Africa, Thailand and Peru, according to the HIV Vaccine Trials Network, which tracks HIV vaccine research. Drug companies involved include Merck, Wyeth, Chiron/NOVAD, Therion, GeoVax and others. Two previous trials in Thailand were failures.

DISEASE HOT SPOTS

In the United States, HIV/AIDS has gone from a lethal epidemic to a chronic disease. New HIV infections peaked in the mid-1980s at about 130,000 cases per year, declined quickly in 1995 when antiretroviral drugs came on the market, and have plateaued at about 55,000 new cases per year, according to the U.S. Centers for Disease Control and Prevention.

South Florida is especially hard hit. In Miami-Dade in 2008, one in every 82 Hispanic men, one in every 60 white non-Hispanic men and one in every 29 African-American men are living with HIV, the Florida Department of Health says.

In Broward, those living with HIV include one in 98 Hispanic men, one in 76 non-Hispanic white men and one in every 42 African-American men.

At the end of 2007, more than 500,000 persons in the 34 states that report such statistics were living with HIV/AIDS.

Worldwide, about 33 million were living with HIV/AIDS, with 2.7 million new infections that year, the World Health Organization says.

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