CDC issues interim HIV prophylaxis measure

In its Morbidity and Mortality Weekly Report of January 28, 2011, the Centers for Disease Control and Prevention (CDC) issued an interim guidance to reduce HIV infection among high-risk individuals. The MMWR reports this guidance as a pre-exposure prophylaxis measure to prevent HIV infection in men who have sex with men (MSM), the population that CDC says accounts “for 53% of the estimated incident infections.” This CDC guidance is based upon results of the Pre-Exposure Prophylaxis Initiative (iPrEX) clinical trial reported November 23, 2010, in the New England Journal of Medicine. Study subjects were uninfected but exposed MSMs.

The PrEP arm of the iPrEX trial demonstrated safety and efficacy of the drug combination oral tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC), in reducing sexually acquired HIV. However, the MMWR article says, “The study findings are subject to at least 5 limitations.” The authors identified these limitations as:

• Low trial numbers, with most participants being in South America, which limits evaluations of efficacy

• Adherence assessment through drug-level testing was not uniformly performed

• No information about long-term health effects of the study drugs in men not infected with HIV was provided

• When measured, actual levels of (low or no) drug in the blood conflicted with adherence self reports, pill counts, and bottles dispensed

• Outside a trial setting, the risk behavior of MSMs and their adherence to the regimen, when aware of the trial results, may be different

CDC says that the success of PrEP is largely dependent on adherence. This interim guidance is needed to avert “various unsafe and potentially less effective PrEP-related practices that may develop among health providers and MSM.” John Folby, retired Director of the Commonwealth of Pennsylvania Aids Drug Assistance Program (ADAP), voiced several concerns for the community once this guidance is adopted.

“The CDC guidance recommends who should be prescribed this drug regimen, but there needs to be an intensive outreach and educational component, so that the uninfected do not misunderstand that this regimen is NOT a vaccine or a cure.”

These drugs are expensive, Folby added, and he questioned how the target population, which is high risk, underserved, and uninfected, will pay for the medication.

“Most third-party payers such as AIDS drug assistance programs and State Medicaid may not pay for or provide antiretroviral therapy in the absence of a confirmed diagnosis of HIV/AIDS,” he said.

The MMWR says this latest interim guidance is the first step in the efforts of CDC and other Public Health Service agencies to develop guidelines on the use of PrEP. After obtaining additional public comment and input from experts, CDC says, it will publish a comprehensive set of PrEP HIV prevention services and guidelines for MSMs at high risk.