No new HIV found in patients in Kaiser PrEP program
by Liz Highleyman
No new HIV infections have been seen so far among more than 650 mostly gay and bisexual men who have received pre-exposure prophylaxis – better known as PrEP – through Kaiser Permanente San Francisco since 2012, according to a report in the medical journal Clinical Infectious Diseases.
"It's tremendously exciting to see PrEP translated from research studies into the real world," study co-author Julia Marcus told the Bay Area Reporter following the September 1 announcement of the results. "Now it's just a matter of getting the word out."
The study also found that about 40 percent of PrEP users reported a drop-off in condom use. Sexually transmitted infections were common, but experts said regular monitoring while on PrEP offers an opportunity for prompt STI diagnosis and treatment.
Marcus, Jonathan Volk, Bradley Hare, and colleagues analyzed patterns of PrEP use among members seen at Kaiser Permanente's San Francisco Medical Center between July 2012 – when PrEP was approved by the Food and Drug Administration – and February 2015. Kaiser Permanente provides health care for more than 170,000 adults in San Francisco.
The FDA approved Gilead Sciences' Truvada (tenofovir plus emtricitabine) for PrEP based in part on data from the large iPrEx trial, which showed that once-daily Truvada reduced the risk of HIV infection for men who have sex with men by 42 percent overall compared to placebo, rising to 92 percent among participants with blood drug levels indicating regular use.
At this summer's International AIDS Society conference in Vancouver, researchers reported that a PrEP Demo Project in San Francisco, Miami, and Washington, D.C., saw good adherence overall, and the two new HIV infections during follow-up were in men with low drug levels.
The Kaiser study is the first to look at PrEP use in regular clinical practice. Primary care providers at Kaiser refer members to a specialized PrEP program. Between July 2012 and February 2015 there were 1,045 referrals for PrEP, and 657 people – or 63 percent of those referred – chose to start daily Truvada. People starting PrEP are tested for HIV and STIs and monitored for side effects at least every three months.
Who opted for PrEP?
PrEP referrals and the number of people starting PrEP began to rise around September 2013, with a steeper increase in May 2014 after the Centers for Disease Control and Prevention recommended that people at substantial risk for HIV infection should consider PrEP.
All but four of the people who chose to start PrEP were non-transgender men who have sex with men, one was a transgender man, and three were heterosexual women.
"Our patients on PrEP were primarily gay men," Hare, Kaiser's director of HIV care and prevention, told the B.A.R. "Much work needs to be done to bring PrEP to other groups at risk for HIV who could benefit from it, including trans women and injection drug users."
PrEP users were more likely than those who decided against it to have multiple sex partners (84 versus 69 percent, respectively), but PrEP users and non-users were about equally likely to report having an HIV-positive partner (30 versus 25 percent). Only one PrEP user reported injection drug use as a risk factor.
People who decided against PrEP cited reasons including low risk for HIV infection, concerns about cost, not wanting to do the required regular follow-up, and concerns about side effects or increasing their sexual risk behavior. Only about 2 percent were ineligible due to medical contraindications such as pre-existing kidney or bone problems, while 3 percent were found to have previously undiagnosed HIV infection.
No HIV, many STIs
No new HIV diagnoses occurred among PrEP users during the 2.5 years of follow-up. The researchers noted that based on data from the placebo arm of the U.K. PROUD PrEP trial, which had a similar high rate of STIs, they would have expected about 35 new HIV infections without PrEP.
"We now have an excellent tool that people can use to reduce their risk for HIV during periods of risk for infection," Volk said. "PrEP works. Now we need to make sure that folks at risk for HIV are able to access this medication."
STIs, however, were common in the study. After a year on PrEP half of study participants were diagnosed with at least one new STI. Of these, 33 percent had a rectal STI, 33 percent had chlamydia, 28 percent had gonorrhea, and 6 percent had syphilis. The Kaiser team reported earlier this year that two HIV-negative gay men on PrEP were newly infected with hepatitis C, with sex being their only apparent risk factor.
The researchers did not compare STI incidence between PrEP users and a matched control group of non-users, so the study could not say whether PrEP use was associated with an increase in STIs. However, data from the San Francisco Department of Public Health show a rise in gonorrhea and syphilis among HIV-negative gay men starting around 2008, well before the advent of PrEP.
Beginning in July 2014 Kaiser members were asked about changes in their sexual behavior after starting PrEP, and 143 people (about one in five) completed the survey. Of these, 56 percent said their condom use did not change during the first six months on PrEP, 41 percent reported a decrease, and 3 percent reported an increase. DPH data show that the proportion of HIV-negative gay men reporting recent condomless anal sex rose from about a third in 2010 to nearly 60 percent in 2014.
"It's remarkable to see that PrEP is so effective at preventing HIV in a setting like San Francisco, even as we're seeing high rates of STIs and other evidence of significant HIV risk," Hare told the B.A.R. "Even though our study shows that PrEP works, it should be used in conjunction with monitoring for side effects and regular testing for HIV infection and other STIs."
In an editorial accompanying the published study, Kimberly Koester and Robert Grant from UCSF suggested that the high number of STIs may in part be attributable to more frequent testing among PrEP users rather than changes in sexual behavior. The findings also show Kaiser members feel comfortable accessing PrEP through their regular health provider rather than a dedicated community sexual health clinic.
"The increased frequency of STI testing offered during PrEP services affords more timely diagnosis and treatment of STIs," they wrote. "What appears to be high rates of STI diagnosis may reflect appropriate use of PrEP by people who have the most to benefit and people staying closer to their medical home for sexual health services."
Koester and Grant added that the new findings further the San Francisco Getting to Zero Consortium's aim of making the city the first to achieve the UNAIDS goals of eliminating new HIV infections, HIV-related deaths, and HIV stigma, using a three-prong strategy of expanded access to PrEP, rapid access to antiretroviral therapy, and retention of HIV-positive people in care.
"The data published by Volk and colleagues demonstrates meaningful progress toward the goal of halting new infections," they wrote.
"These data are the greatest proof yet that a PrEP clinic delivering this intervention as thoughtfully as Kaiser has can be a major force in reducing new HIV infections," Dana Van Gorder from Project Inform told the B.A.R. "We have yet to see whether a less well-funded health center serving a poorer and more diverse population of individuals can perform as well, but there is good reason to believe they can."