April 12, 2011
As I look back over the recent past in HIV research, I am impressed at what advancements we have made, yet disturbed at what little we know and have done regarding HIV prevention and treatment in women.
It seems like only yesterday (actually 1993) that reproductive-age women were allowed to enter clinical trials. That was a banner day! We've come a long way, baby. But as women we have a long way to go to catch up with male enrollment in clinical trials. Most drug trials -- whether regarding diabetes, hypertension or HIV -- have been largely conducted on white, middle-aged men; that data were then generalized to all genders and races. Excuse me, but we aren't all white men!
The GRACE Study is a landmark clinical trial that was designed to recruit and retain women and people of color. It was conceived in 2006. Unfortunately, I have yet to see this replicated in other large-scale clinical trials. There are differences between men and women! Hello? Has anyone noticed?
Currently, one of the hottest topics in HIV prevention research is that of pre-exposure prophylaxis (PrEP) to prevent HIV transmission. The most noteworthy study in this field to date is the CAPRISA 004 trial, which featured a vaginally applied gel containing tenofovir (Viread) and showed that a two-dose modality of this gel offered women a statistically significant level of protection from acquiring HIV infection vaginally.
The second study was the iPrEx study, which showed that a once-daily pill of the combination drug tenofovir/emtricitabine (Truvada) also reduces the risks of acquiring the virus among men who have sex with men (MSM). Based on these findings, the U.S. Centers for Disease Control and Prevention (CDC) released interim guidance on the use of PrEP by MSM -- and only MSM.
I'm awaiting the outcome of research in women around reproductive issues, especially for HIV-uninfected women in a serodiscordant, heterosexual relationship in which the male partner is HIV infected. For instance, HPTN 052 is a phase 3, two-arm study of two different treatment strategies (immediate treatment initiation versus deferred treatment initiation) in preventing the sexual transmission of HIV in HIV-serodiscordant couples. This study grew out of the theoretical correlation between HIV viral load and HIV transmission. Specifically, the higher the viral load in the blood, the more likely the chance for transmission. Antiretroviral therapy (ART) reduces the viral load in the blood, as well as in genital secretions (for both men and women), and the drugs can be detected in semen and vaginal/cervical secretions. All of this information strongly suggests that ART may make HIV-infected people less infectious during unprotected sex.
HPTN 052 compares the HIV infection rates of two groups of HIV-serodiscordant couples. The index case of the first group starts taking ART as soon as the couple is enrolled in the study, while the index case of the second group starts taking ART when the HIV-infected male or female partner has two consecutive measurements of a CD4+ cell count within or below the range of 200-250 cells/mm3, or when he or she develops an AIDS-defining illness. Both groups will receive HIV primary care and couples counseling sessions to teach them how to reduce their risk of transmission.
HPTN 052 has closed accrual with approximately 1,750 couples in nine countries (primarily Brazil, India, Malawi, Thailand and Zimbabwe), who will be followed for 60 months.
There is also another trial in development worth noting: HPTN 067, called the ADAPT study. This is a behavioral study to evaluate the feasibility of intermittent dosing of a PrEP regimen (specifically, oral tenofovir/emtricitabine). Recommendations for intermittent usage, compared with daily usage, may provide comparable coverage of possible exposures with pre- and post-exposure dosing, decreased pill requirements, and decreased symptoms. The population studied will include women at high risk for HIV infection.
This is a very exciting time in research for women! So what can you do? Researchers should proactively design clinical trials with a strong recognition of the distinctive needs for, and barriers to, the recruitment and retention of HIV-infected women. Studies should be designed to include financial assistance to cover costs associated with transportation, food vouchers and child care; counseling and emotional support from clinicians and other HIV-infected women; employment time restraints; family commitments; and other psychosocial issues.
Meanwhile, what we can do as health care providers is to keep abreast of research in women and improve opportunities for our female patients and clients to participate in clinical trials.