US PrEP study achieves high levels of engagement and adherence among black men who have sex with men

What was described at the 21st International AIDS Conference (AIDS 2016) as “the first PrEP trial devised and run by four black gay men” has shown that high levels of PrEP (pre-exposure prophylaxis) use, retention and adherence can be achieved in a demonstration project if its recruitment and support structures are tailored to the needs of black men who have sex with men (BMSM). 

Although the HPTN073 “My Life, My Health, My Choice” study which recruited 226 participants, was too small to demonstrate a statistically significant reduction in HIV cases, HIV incidence was 62% lower in men electing to take PrEP during the study than the minority who never did.

Although BMSM only form 0.4% of the US population, 20% of new HIV infections occur in this group. Fifty-seven per cent of African Americans diagnosed with HIV are MSM, and HIV incidence in black MSM under 25 has nearly doubled in the last decade. However other PrEP demonstration projects such as the ADAPT study have found lower uptake of and adherence to PrEP in black MSM than in other groups, and particularly in young men.

About the HPTN073 study

Darrell Wheeler of the State University of New York introduced the study and its findings. Three hundred and forty-four BMSM were screened for the study and of these, 226 were enrolled. Reasons for exclusion included 40% for medical reasons including 21% who had tests indicating liver or kidney problems. Six per cent screened turned out to have HIV.

The year-long study took place at three sites in Los Angeles, Washington DC and Chapel Hill, North Carolina, with sites recruiting between August 2013 and September 2014.

A poster presented at the conference (Hightow-Weidman 2) showed high levels of co-morbidities in those who did enrol: 30% had a diagnosed psychiatric condition, 15% a cardiovascular condition, and two-thirds had at least one ‘clinically significant co-morbidity’.

Participants were offered significant support in a programme of so-called client-centred co-ordinated care (C4) operated by an inter-disciplinary team, which assessed them for sexually transmitted infections (STIs), other illnesses, psychiatric condition and gave counselling and prevention support. On average participants taking PrEP attended six of these C4 sessions and those who chose not to attended four sessions.

In a separate presentation Christopher Hucks-Ortiz, who chairs the HIV Prevention Trials Network Black Caucus, said that the trial was also strongly embedded within local communities. All trial staff ranging from physicians to receptionists were given cultural responsiveness training, and there was a specific work plan with targets around engagement of the local community with the trial.

Wheeler said that 79% of men enrolled chose to take PrEP, in the form of daily Truvada, with 92% retention over the twelve months.

PrEP uptake varied by site, as did retention. In Chapel Hill 88% started PrEP and 67% were still taking it at the end of the study; in Washington DC 79% started and 60% were still taking it at month 12; in Los Angeles the figures were 68% and 51% respectively. Most people who started PrEP did so immediately, except in Los Angeles, where a significant minority delayed starting by a few weeks. A higher proportion of young men (under 25) started PrEP – 84% – and 96% of those with an HIV-positive primary partner started it.

Of the participants, roughly three-quarters defined as gay, 20% as bisexual and 7% as heterosexual or other. A third had a primary male partner and a third of those partners had HIV (only three individuals had a primary female partner). Ninety per cent defined as black American or Caribbean; most of the rest were mixed black/Latino.

Nearly half (48%) of participants earned less than $20,000 a year but 23% earned more than $50,000. A considerably higher proportion of those who were screened but not enrolled had an income of under $20,000 a year (63%).

Sixty-nine per cent had at least some healthcare insurance coverage and 75% had some tertiary education. But more than a quarter (27%) were unemployed or on disability benefit and 30% had been in prison at some point.

Adherence and HIV infections

Two-thirds of men throughout the trial self-reported adherence of more than 90%, and 85% reported more than 50% adherence. The only factors significantly associated with low or high adherence were poly drug use (self-reported adherence 50% lower than average) and having a primary partner (75% higher than average). There was a trend to better adherence among participants with more education.

Directly-measured drug levels correlated well with self-reported adherence, especially near the start of the trial, though it tailed off somewhat later. Eight weeks into the trial, 67% of men had drug levels in blood consistent with taking four or more doses of PrEP a week but by week 52 this had declined to 56%. Interestingly at week eight drug levels in cells were a little lower than those in blood (61% consistent with four or more doses a week) but at weeks 26 and 52 they were exactly the same. This may indicate how slowly drug levels reach a steady state in tissues.

There were five HIV infections among men who started PrEP versus three in those who did not. But because many fewer men elected not to start PrEP, this translates to a considerably reduced annual incidence in men starting PrEP: 2.9% versus 7.7%, representing a 62% reduction in incidence, though because of the size of the trial this difference was marginally statistically non-significant. Two of the five men who started PrEP but still caught HIV were known to have stopped taking PrEP more than seven weeks before they tested HIV-positive.

Sexually transmitted infection and condom use

Another presentation (Hightow-Weidman 1) looked as STIs and sexual behavior in the study. Self-reported condomless sex actually declined over the course of the study. At the start of the study 46% of men reported condomless insertive anal sex at last sex and 45% receptive; by week 52 this had declined to 34% and 32%, respectively, though these declines were not significant. Condomless sex with known HIV-positive partners did not change, staying at 15% insertive and 8% receptive.

STI diagnoses increased somewhat during the study, though non-significantly. At baseline 14% were diagnosed with an STI, with a considerably higher rate among under-25s (35% versus 6.7%, or 4.39 times the risk). This equated to an annual incidence of 31%; 33% in those who started to take PrEP and 27% in those who decided not to.

By week 52, annual STI incidence had declined in those not taking PrEP (23.5%) but had increased in those taking PrEP (38%), though again these differences were not statistically significant. Altogether, 60 of 226 participants (26.5%) acquired an STI during the study, with some acquiring several.

Wheeler commented that the study had shown that the answer to whether BMSM would utilise PrEP was “a resounding Yes” if they were engaged and supported in culturally-appropriate ways, though he did add that the slight decline in adherence and HIV incidence of nearly 3% even in those who started PrEP showed that there was room for further improvements in PrEP such as injectable formulations.