Desperate AIDS patients already are calling doctors to see how they can get a new drug that is warding off the virus in monkeys at a Medical Lake laboratory.
The research breakthrough was announced earlier this week at the University of Washington Regional Primate Center, where doctors have tested anti-viral drugs for the past nine years.
The drug PMPA successfully blocked the infection of 25 monkeys who were exposed last year to SIV, the primate version of HIV, which causes AIDS. Today the monkeys are healthy and strong, even though they were injected with 10 times the amount of SIV known to cause infection.
AIDS experts are calling the results “unprecedented,” but researchers say they won’t allow human tests of PMPA until sometime in 1996.
Doctors also are warning AIDS patients that PMPA is not a cure for people who already have the virus.
For now, though, the breakthrough is giving some people hope, said Norbert Bischofberger of Gilead Sciences Inc. in Foster City, Calif., which manufactures PMPA.
“Of course there are qualifying factors like people are people and monkeys are monkeys,” Bischofberger said. “But this is the first time we’ve had results that give us reason to believe there’s something here we haven’t seen before.”
Bischofberger said plans call for PMPA to be on the market by the middle of next year.
Experts at the National Institutes of Health hailed the latest results as the most promising so far in AIDS research. A daily dose of the drug was given to the monkeys for four weeks, with no trace of the infection in their blood or lymph nodes more than a year later.
Such protection, along with no toxic side effects, makes PMPA unique, they said.
“It’s exciting because no other drug … has had this effect,” said Tom Beck, a scientist who assisted in the Medical Lake research project. “It works better than any we’ve seen.”
Beck said dozens of people with HIV called the laboratory throughout the day Friday, wanting to know when they could get PMPA or if they could volunteer for human testing.
More calls came to the Spokane AIDS Network office on West Gardner, where a receptionist fielded questions about the drug from hopeful patients. Others called the Spokane County Health District and local doctors who specialize in HIV.
The patients wanted to know when PMPA would be available, how it works and if it could help them. Some just wanted to see whether the results they heard about were true.
Unfortunately, Beck said, the results may be more promising for people who are exposed to HIV and then immediately use the drug to protect them from infection.
When PMPA was given to monkeys 20 weeks after they were exposed, it lowered the levels of the virus in their blood but did not eliminate it, Beck said.
It prevented SIV in the 25 monkeys who were treated either 48 hours before, four hours after or a day after being injected with the virus, he said.
Those results could prove useful to health care workers who are accidentally exposed to HIV.
It also could be given to people who find out they have recently had sex with an infected partner, as is the currently used AZT.
While similar to AZT, PMPA is more potent and can stay inside cells longer, enabling them to fight harder, according to an article in Friday’s edition of the journal Science.
The drug AZT often fails to protect people who take it after being exposed to the virus, researchers said.
“PMPA is certainly something to celebrate,” Bischofberger said Friday. “It’s given us hope that it will translate into something very useful, something big.”
Gilead Sciences also is researching drugs for AIDS-related blindness, herpes and human papilloma virus.
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