Combivir Non-Occupational PEP Study Finds Low Adherence Rates

  • Adherence to AZT/3TC (Combivir) as Post-Exposure Prophylaxis in Non-Occupational HIV Exposures (MoPeD3694)
    Authored by A.A. Moe
    View the original abstract

It is well known that adherence to complex antiretroviral regimens is an essential factor in the success of treatment for HIV-infected individuals. While less information about the role of adherence in post-exposure prophylaxis (PEP) is known, it can be reasonably assumed that adherence is of similar importance in this setting. Additionally, characterization of the kind of behaviors that place persons at risk for exposures is an important element targeting prevention strategies (see other presentations on this subject: abstracts 1196, 1197, 1200).

Dr. A. Moe and colleagues at UCLA undertook this study to evaluate the use of co-formulated AZT/3TC (Combivir) in a group of 100 persons who had non-occupational exposure to HIV. One-hundred study subjects were recruited from the Los Angeles area and were represented largely by homosexual men. In an interview, Dr. Moe stated that people for the study were recruited rapidly, suggestive of a high frequency of risky behaviors in this population.

Strikingly, nearly half of the subjects reported having unprotected intercourse while taking either alcohol or other recreational drugs; 70 percent had intercourse without the use of condoms. Over a third of subjects reported frank alcohol intoxication on greater than two of the past 30 days.

A large number of study subjects failed to complete even two follow-up visits (27 percent) and very few completed the six-month follow-up visit. One person eventually became HIV seropositive in the cohort, but this was noted 18 months after recruitment, making assignment of the time of infection difficult. Of the 67 percent of subjects who completed both two- and four-week follow up, 82 percent of persons reported greater than 90 percent adherence to the twice-daily regimen. Seventy-nine percent of subjects reported one or more mild side effect (usually related to the AZT component) -- namely nausea, fatigue or dizziness. There were no serious side effects (grade III or IV) on treatment.

The author concluded that recreational drug and/or alcohol intoxication plays a significant part in risky behaviors. Perhaps because of this, she found a high demand for PEP, even with the known side effect profile of medications. The lack of long-term follow up on therapy limits any ability to evaluate the efficacy, but speaks to the need to address follow-up issues in the design of future studies. Dr. Moe suggested that one way to accomplish this might be to provide payment for persons returning for study visits.

Though this study has significant limitations, I was struck by how often recreational drug use places persons at risk for HIV exposures. Understanding the nature of risky behaviors deserves much attention in prevention strategies -- a fact that counseling must address.