The pill that prevents HIV infection
In July 2012, the Food and Drug Administration approved the sale of Truvada for pre-exposure prophylaxis (PrEP) for the prevention of HIV transmission. With many men reluctant to use condoms, public health officials thought gay men in particular would be lining up at the pharmacy to get their prescriptions filled to protect themselves from getting infected.
Yet demand for the pill, which includes two antiretroviral drugs, has been disappointing at best. The New York Times recently reported a mere 1,774 prescriptions were filled for Truvada for HIV prevention through March of 2013, more than half of them for women. It raised the question why gay men weren’t more receptive of a drug that in clinical trials showed could cut the odds of getting HIV by 96 percent. Even condoms don’t have a prevention rate that high. A study in Thailand found the drug could reduce the risk of HIV transmission among IV drug users by 49 percent.
Critics of the pill have suggested that men might engage in riskier behavior if they don’t perceive a risk of HIV infection, which could then expose them to other sexually-transmitted diseases or even paradoxically raise the risk of HIV infection if they abandon other risk mitigation strategies. And if men don’t take the pill every day, they might not have any protection at all.
“I think there was a lot of fear that if we do this and promote it, people are going to throw caution to the wind and do whatever they want,” said Michael Anderson-Nathe with the Cascades AIDS Project in Portland. “In places that have used PrEP, that hasn’t panned out.”
Others have questioned whether results of the study testing Truvada’s prevention potential were reproducible in the real world. Those participating in the study also received counseling on condom use and other safe-sex strategies, and they did not know whether they were truly on the medication or taking a placebo. It’s possible they could have been more diligent about protecting themselves than people would be if they knew for sure they were taking the medication.
Some have also questioned the wisdom of giving medications, which can have intense side effects, to perfectly healthy individuals, particularly when thousands of HIV-positive individuals around the world don’t have access to antiretrovirals. Then there’s the $1,000 per month cost of the drug.
Proponents argue that Truvada is another tool in the toolbox, and many advocate a “suspenders and belt” approach, using the PrEP along with other risk reduction methods, such as condom use.
“There are certain people who would benefit,” Anderson-Nathe said. “Think about people who are in a mixed-status relationship, they’re not throwing caution to the wind, but they are at higher risk.”
Are we nearing a cure for HIV/AIDS?
Increasingly researchers have been talking about HIV/AIDS cures instead of treatments. Treatment with antiretroviral drugs can create a functional cure, where the virus is completely suppressed and does not replicate, even after the patient stops taking antiretroviral drugs. A more complete cure, known as a sterilizing cure, requires the eradication of all HIV from a person’s body. There are only two people, so far, who are considered to have achieved a sterilizing cure. But even those cases remain controversial.
Known as the Berlin Patient, Timothy Brown is the first person ever considered cured of HIV/AIDS. Brown was diagnosed with HIV in 1995 and took antiretroviral drugs to keep the virus in check for 10 years. Then he developed acute myeloid leukemia, which doctors in Berlin, Germany, treated with a bone marrow transplant in 2008. Because he was HIV-positive, the doctors chose a donor who was one of 1 percent of Caucasians to have a gene mutation that makes them immune to HIV. Brown has been off antiretrovirals for more than five years now and remains HIV-free.
In October 2013, doctors reported that a 3-year-old Mississippi child, who had been treated for HIV unusually early, remained HIV-free 18 months after she stopped taking antiretroviral drugs. The child was born to an HIV-positive mother and tested positive immediately after birth. Doctors started antiretroviral treatment within 30 hours of the delivery, and within a month the viral levels were undetectable. The baby remained on the mediations for 18 months, but was lost to follow-up. When the doctors saw the child 10 months later, they learned the mother had stopped the drug therapy, yet the infant was free of any HIV infection.
Doctors in France reported last year about a group of HIV patients known as the Visconti cohort, considered to have a functional cure. The patients began taking antiretroviral drugs within weeks of being infected. They continue to have detectable HIV in their blood, but have been off of the drugs for an average of seven years without any signs that the infection is progressing. The researchers cautioned that only 10 to 15 percent of individuals treated in this rapid timeframe have been able to achieve a functional cure.
Physicians in Boston thought they had recreated the Berlin Patient cure in two patients who underwent bone marrow transplants and then agreed to stop taking their medications to see whether the transplant was keeping the virus under control. In July 2013, after one patient had been off medications for 15 weeks and another for 7, doctors announced they could find no trace of the HIV. Doctors were cautiously optimistic at the time, noting the virus could return “next week.” The virus returned in August in one of the patients, and in November in the other.