This Week in HIV Research: The Duracell Batteries of Antiretroviral Therapy
This week, we learn about data from a large study exploring the relative durability of first-line antiretroviral regimens stratified by drug class. (Spoiler alert: Older protease inhibitors don't do so well.) We also take a look at a couple of PrEP-related studies -- one highlighting the limitations of current CDC PrEP guidelines, the other on the power of text messages to improve adherence -- and then wrap up with new findings about the potential value of HPV vaccination among HIV-positive men who have sex with men and transgender women.
To beat HIV, you have to follow the science!
Integrase Inhibitors, NNRTIs Appear More Durable Than Protease Inhibitors
People living with HIV who start treatment on integrase inhibitor- or NNRTI-based regimens are less likely to see their medications changed than those on protease inhibitor-based treatments, a retrospective study published in AIDS found.
Forty-three percent of the 5,373 participants had their first drug regimen modified. Protease inhibitor-based regimens were modified most quickly -- 32 months, on average, among those who changed treatment -- compared to integrase inhibitor-based regimens (44 months) or NNRTI-based regimens (61 months).
Over the course of the study (2007-2015), the overall percentage of participants whose drugs were changed due to virologic failure dropped from 50% to 10%. The study did not investigate the reasons for other prescription changes, but study authors speculate that some switches may have been occasioned by the advent of better tolerated, simplified regimens rather than problems with the old medications. Indeed, among all drugs, the newest combinations were least likely to be changed.
Regimen durability was unevenly distributed among demographic groups, with treatment changes more common among women, young people, African Americans, and people who use intravenous drugs. Study authors called for further evaluation of the antiretroviral treatment challenges faced by these populations.
CDC PrEP Guidelines Don't Adequately Cover Young African-American Men
U.S. Centers for Disease Control and Prevention (CDC) guidelines may be inadequate to determine which young African-American men who have sex with men (MSM) would benefit from pre-exposure prophylaxis (PrEP), a study published in AIDS showed.
Researchers analyzed data on about 300 16 to 29-year-old young black MSM in Chicago between 2013 and 2016. The seroconversion incidence rate was 8.5 per 100 person-years, compared to the World Health Organization's high HIV prevalence definition of 3 per 100 person-years. Almost half of those who acquired HIV were not eligible for PrEP according to CDC guidelines.
The best predictor for who might seroconvert turned out to be participants with a sex partner who is at least 10 years older, a factor that is not accounted for in the guidelines. Only 10% of those who did meet guideline criteria for PrEP had ever taken the medication.
Researchers noted that the guidelines are based on individual-level behaviors, rather than population-level factors, and called for offering PrEP to everyone in that population who is in a high-prevalence area.
Daily Text Messages Appear to Improve PrEP Adherence
Daily text messages may help keep people who are taking PrEP on track, the TAPIR trial published in Clinical Infectious Diseases found.
Almost 400 MSM and transgender women in Southern California received either: 1) daily text messages that were automated but personalized; or 2) brief in-person prevention and adherence counseling, which is the current standard of care. Participants were then tested for study drug concentrations after 12, 24, 36 and 48 weeks. Seventy-four participants dropped out of the study early, leaving 324 people at week 48.
Texting was especially beneficial during the early weeks: 47.5% in the intervention arm had taken PrEP in the 24 hours before the week 12 visit compared to 33.3% in the standard of care arm. The messages also helped to sustain near-perfect adherence over 48 weeks, but did not make much difference for those who showed minimally effective levels of the medication.
Researchers cautioned that real-world adherence is likely lower than in a study, but recommended the intervention as a "low burden" tool that may be helpful for long-term adherence.
Study Findings Back HPV Vaccine for U.S. MSM
Two-thirds of young, mostly African-American MSM carried at least one human papilloma virus (HPV) type included in the HPV vaccine, a study published in The Journal of Infectious Diseases found.
More than 90% of study participants who live with HIV had such an HPV type, compared to 32% of those not living with the virus. Study authors recommended prioritizing HPV vaccinations among that population.
A related study of HIV-positive people published in the same journal issue reported higher HPV prevalence rates in MSM compared to men who have sex with women. Both groups cleared HPV at about the same rate, but those who reported condomless receptive anal sex or methamphetamine use took longer to clear the virus.
The study authors recommended that men who live with HIV be counseled on drug use and safer sex practices, as well as vaccinated against HPV and treated early for HIV to help their immune systems clear HPV.