Challenges in the March Toward an AIDS-Free Generation

FDA’s approval of Truvada, a once-a-day oral combination of tenofovir and emtricitabine, for pre-exposure prophylaxis (or PrEP, a method for preventing HIV infection) arrived during a chorus of optimism surrounding major developments in the fight against AIDS.

At conferences in the UK and the US last month, the possibility and even likelihood of an AIDs-free generation in our lifetime graced the lips of innumerable activists, academics and government officials including Secretary of State Hillary Clinton and NIH director Francis Collins. “I honestly believe,” rock star Sir Elton John told an audience at the International AIDS Conference in Washington DC, “that before I die, I will more or less be seeing the remains, the last remaining people infected with AIDS.”

Much of this optimism is a result of the HIV Prevention Trials Network (HPTN) – an international collaborative clinical trials network – and the findings from its key study, HPTN-052. That study was halted last April after demonstrating that HIV-infected individuals, when treated with antiretroviral therapy (ART), experienced an astonishing 96% reduction in transmission of HIV to an uninfected partner.

Prior to that discovery, the National Institute of Allergy and Infectious Diseases (NIAID), in partnership with the Bill and Melinda Gates Foundation and Gilead Sciences, sponsored the iPrEx study, which looked at uninfected men who have sex with men, and transgendered women who have sex with men, with an eye toward prevention. That study, which served as the basis for Truvada’s PrEP indication approval, found that study participants who took a daily dose of Truvada experienced an average of 43.8% fewer HIV infections than those receiving placebo. Study participants who said they took the drug 90% of the time – 100% representing perfect, daily adherence – had 72.8% fewer HIV infections, a finding that points to the necessity of adherence for full benefit.

Combine these studies with viral load testing capabilities and comprehensive educational measures, and the picture starts to look almost rosy, despite a continuing need for access to education, testing and ART in many parts of the world. The case for treating HIV-positive patients with ART as a preventative measure – known as Treatment as Prevention, or TasP – is easily justified in environments where healthcare coverage is accessible and affordable, particularly for patients who want to begin treatment earlier. As for prescribing Truvada in “high-risk individuals” as a protective measure, many questions remain, not least of which is cost-effectiveness.

Of the 48,000 to 56,000 new HIV infections in the US each year, 56% to 61% occur among men having sex with men (MSM), according to original research published in the Annals of Internal Medicine last April. Within the MSM population, researchers designated 20% as “high-risk;” in the high-risk population, Truvada provided considerable savings, with a caveat. “Because PrEP provides the most value in reducing HIV transmission when used in high-risk MSM, efficient clinical PrEP will depend on a clinician’s ability to identify high-risk MSM,” according to the authors. Indeed, it will be critical for physicians to determine who’s high risk and who isn’t, by asking questions about frequency of condom use and the number of sexual partners a man has had in the last year; the research points to diminishing returns cost-wise when PrEP is used in larger MSM populations, beyond the highest-risk populations.

At the joint International Association of Physicians in AIDS Care (IAPAC) and British HIV Association (BHIVA) conference in London, Michael Horberg, director of HIV/AIDS at Kaiser Permanente, estimated that PrEP treatment – including lab work and appointments, would cost private payers approximately $17,450 for the first year of treatment. These costs are estimated for MSM populations only. At the same conference, Jim Rooney, Gilead’s VP, medical affairs, said stakeholder meetings were underway in the US to get feedback on PrEP use in MSM populations, but “subsequent meetings have included discussion of PrEP in heterosexuals as well.” Gilead will provide education via third parties, and will not promote the drug directly, said Rooney.

Will payers get behind an expensive preventative treatment that only makes sense for patients carefully selected by physicians educated on high-risk MSM lifestyles, and willing to ask the necessary questions? Will payers pony up for a treatment that only works half of the time if patients don’t strictly adhere to the daily dose? Truvada looks to be a solid test case in the ongoing value discussion. Pay for an expensive new drug now, or a potentially more expensive condition later?