WASHINGTON — Should doctors prescribe to healthy people engaged in high-risk behavior an $11,000-a-year drug that is not as effective as condoms in preventing HIV infection?
That question created some of the most heated debate at the 19th International AIDS Conference in Washington this week.
When opponents argued that such a drug would give users a false sense of security that would discourage condom use, scientist Linda-Gail Bekker said: “Do people think that if we give people more statins (drugs to lower cholesterol), they will eat more ice cream? Why don’t we ever ask that?”
Concerns were also raised about the allocation of resources and the danger of creating resistance to drugs that are invaluable in treating those already infected.
The debate was inspired by a prevention tool called pre-exposure prophylaxis, or PrEP, which involves giving antiretroviral drugs to HIV-negative people who are at high risk of infection.
On July 16, the Food and Drug Administration approved the first drug for PrEP in the United States — an oral, once-a-day pill called Truvada. The drug, marketed by Gilead Sciences, is for healthy, high-risk individuals such as gay men and partners of HIV-positive people.
In 2010, a clinical trial demonstrated a 39 percent decrease in the chance of contracting HIV for at-risk women in South Africa who were given Truvada in the form of a vaginal microbicide. It was the first trial to show that PrEP could work.
Another study showed that gay and bisexual men who took a daily pill of Truvada reduced their risk of infection by 44 percent. Two more trials involving heterosexual men and women in southern Africa showed an efficacy of up to 75 percent.
By comparison, circumcision is about 60 percent effective in preventing HIV infection.
Next to abstinence, condom use is the most effective preventative — 90 to 95 percent if used consistently.
In addition to concerns about discouraging condom use, opponents raised ethical issues about cost. Fewer than 50 percent of people worldwide with HIV are receiving the treatment they need, according to the United Nations Program on HIV/AIDS.
Moreover, many other diseases and illnesses are rampant, including those that are inexpensive to prevent or treat.
Truvada is estimated to cost about $11,000 annually per person, and generic versions of the therapy will not be available until Gilead Sciences’s patent expires in 2021.
Nelly Mugo, a leading HIV-prevention expert at the Kenyatta National Referral Hospital, said PrEP could be an empowering tool for vulnerable populations such as people living in places where rape is used as an instrument of war. Mugo notes that the tactic gives women a prevention tool that they can control.
Harvard scientist Douglas Krakower said that the full benefits can be achieved if physicians are trained to prescribe and monitor its use responsibly as part of a “prevention package” that includes condom use and behavioral counseling.
Krakower added that consistent HIV testing would have to be carried out for those on PrEP to ensure that they would not unknowingly become infected while taking antiretrovirals — a dangerous opportunity for their viral strains to gain resistance to drugs.
Mugo proposed that patients be provided newly approved “HIV home testing kits” that could be coordinated with renewals of PrEP prescriptions.”If later evidence says (prescribing PrEP isn’t a good idea), I think it’s within the Hippocratic oath to change my mind.”
Heated discussion after presentation sessions made it clear that physicians remain divided about prescribing Truvada or other PrEP drugs that are in the pipeline. One doctor, referring to the fact that condoms are cheaper and more effective, shouted angrily to Krakower, “How is this not a violation of the Hippocratic oath?”
He responded, “I think it’s a violation of the oath to withhold strategies that may be protective.” He added that PrEP development is a young and rapidly evolving field.