July 20, 2010
The effort to fight HIV/AIDS in the developing world has been ramping up since President George W. Bush launched the President’s Emergency Plan for Aids Relief in 2003. This year the U.S. will spend over $4 billion treating people with the sexually transmitted disease in poor countries, and the rest of the advanced industrial world spends nearly as much.
But with governments everywhere under budgetary pressure to limit foreign aid, the treatment campaign faces an uncertain future. Finding something that can radically reduce the number of new persons becoming infected has become the front burner issue for AIDS researchers and global public health officials.
Their hopes for a breakthrough got a major shot in the arm Monday when U.S. government-backed researchers unveiled the results of a clinical trial that showed a vaginal gel can limit the spread of the infection by 39 percent. If women routinely used the gel within a dozen hours before and after sex, the risk of contracting AIDS from an infected partner was reduced by 54 percent.
“If we can break the chain of transmission in young women,
we can begin to affect the curve of the epidemic.”
“This is the first product that woman can initiate and affect the underlying trends of the epidemic,” said Quarraisha Abdool Karim, associate scientific director of the Center for the AIDS Program of Research in South Africa, which conducted the trial.
Karim has been studying the epidemiology of the AIDS epidemic in South Africa, one of the hardest hit countries in the world, since the early 1990s. She’s watched every new generation of young women become infected at extraordinarily high rates – up to 8 percent of each cohort – by older men who have multiple sexual partners and refuse to wear condoms.
Reached by phone in Vienna, where the global AIDS research community is holding its annual conference, she said, “This is the first thing that we can give to women where they can control its use. If we can break the chain of transmission in young women, we can begin to affect the curve of the epidemic.”
The campaign to develop a female-centered technology that slows or stops transmission has been littered with failures. A previous vaginal gel taken through clinical trials by CONRAD, the U.S.-backed nonprofit drug developer that took this latest vaginal gel into clinical trials, actually increased the rate of HIV transmission among its users.
But the latest test backed by CONRAD added a Food and Drug Administration-approved antiretroviral drug called tenofovir, provided by California-based Gilead Sciences Inc., to the gel. The trial randomly divided 889 women whose average age was 23 into two groups, only one of which got the gel with drug. After 30 months, there were 60 infections in the placebo arm compared to only 38 in the drug arm.
“The efficacy is not overwhelming, and there will need to be confirmatory studies, but this looks like a good candidate for women to protect themselves,” said Henry Gabelnick, executive director of CONRAD. “We’re going to add other compounds to see if we can’t increase its efficacy.”
Based on the results achieved in this trial, researchers estimated widespread use of the vaginal gel could prevent 1.3 million infections and 800,000 deaths over the next two decades.
Cost will remain a stumbling block to widespread dissemination should the confirmatory trial prove successful and lead to regulatory approval in the U.S. and Europe. The drug, licensed by Gilead to generic manufacturers in the developing world, will only be 2 cents per application. However, the applicator and ancillary production costs is currently estimated at 30 cents – a stiff price for some sub-Saharan countries hard hit by the epidemic, where average wages can be as low as $2 a day.
If CONRAD and the development team it helped coordinate are as successful in bringing down the production costs as they were in holding down its development costs, it shouldn’t be an insurmountable issue. The clinical trial cost less than $20 million, with $1 million coming from the South African government, and less than $17 million from the U.S. government. Gabelnick estimated there was several million dollars in pretrial development work.
Gilead agreed to license its gel technology at no cost to two South African nonprofits, and its drug to two manufacturers in India and South African manufacturers for a 5 percent royalty payment. “This has been a real public-private partnership,” said Gabelnick.