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No New HIV Infections Seen So Far in Kaiser San Francisco PrEP Program

, by Liz Highleyman

Kaiser Permanente’s San Francisco Medical Center has seen a dramatic increase in the number of members taking Truvada for pre-exposure prophylaxis (PrEP) since 2012. To date, there have been no new HIV diagnoses among PrEP users during the two and a half years of follow-up.

Some men taking PrEP did report a drop-off in condom use, and rates of sexually transmitted infections (STIs) were high. A  total of 344 STI diagnoses were made among participants during the observation period with a PrEP protocol mandating frequent STI testing and prompt treatment.

Bradley Hare, MD. Photo courtesy of UCSF.

Bradley Hare, MD  (Photo courtesy of UCSF)

Findings from the Kaiser PrEP study, which included 1,045 mostly gay and bisexual men who were referred for evaluation and 657 who decided to start PrEP, were reported in the September 1 advance edition of Clinical Infectious Diseases. Brad Hare, MD, Kaiser’s director of HIV care and prevention, presented preliminary findings about the Kaiser PrEP program at a World AIDS Day forum in December 2014.

“Our observations are important primarily because they extend what is known about PrEP from the controlled setting of clinical trials and show that it works in the ‘real-world’ as well,” Hare told BETA. “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.”

Jonathan Volk, MD (photo: Liz Highleyman)

Jonathan Volk, MD (photo: Liz Highleyman)

Hare, Jonathan Volk, MD, and their colleagues looked at patterns of PrEP use among members of the large Kaiser Permanente San Francisco healthcare system between July 2012—when the Food and Drug Administration approved Truvada (tenofovir + emtricitabine) for PrEP—and February 2015.

The FDA approval was based in part on data from the large international iPrEx trial of mostly men who have sex with men, which showed that once-daily Truvada reduced the risk of HIV infection by 42% overall compared to placebo, rising to 92% among participants with blood drug levels indicating regular use.

At this summer’s International AIDS Society conference in Vancouver, researchers reported that participants in a non-randomized PrEP Demonstration Project in San Francisco, Miami, and Washington, DC, had good medication adherence overall. The two new HIV infections that occurred during follow-up were in men with low drug levels at the time of seroconversion. Thus far, there has not been much data reported about PrEP use in regular clinical practice.

At Kaiser, primary care providers refer members to a specialized PrEP program after a risk assessment or when patients request it. Before beginning PrEP, in-person evaluations are conducted and then people interested in PrEP receive an intake visit where they are tested for HIV infection and STIs and screened for medical contraindications to Truvada such as pre-existing kidney or bone problems. The program provides adherence support and clinical monitoring including HIV and STI screenings every one to three months. Beginning in July 2014 participants were surveyed about changes in their sexual behavior after starting PrEP.

Between July 2012 and February 2015 there were 1,045 referrals for PrEP. A total of 835 (80%) people completed an in-person evaluation and 801 (77%) completed an intake visit. A total of 657 people—or 63% of those referred—chose to start PrEP.

HIV PrEP referrals, intakes, and initiation by month at Kaiser Permanente San Francisco, July 2012 – February 2015

HIV PrEP referrals, intakes, and initiation by month at Kaiser Permanente San Francisco, July 2012 – February 2015

The 144 people who decided against PrEP after completing an intake visit cited reasons including low risk for HIV infection, concerns about cost, not wanting to do the required regular follow-up, preferring post-exposure prophylaxis or PEP, concern about side effects, and worry about potentially increasing their sexual risk behavior. Only a small number of people were ineligible for PrEP for medical reasons, including 3% with pre-existing HIV infection and about 2% with impaired kidney function or osteoporosis (bone loss).

The researchers noted that PrEP referrals and the number of people starting PrEP began to rise around September 2013, with a steeper increase starting in May 2014, after the Centers for Disease Control and Prevention (CDC) recommended that people at substantial risk for HIV infection should consider PrEP.

All but four of the people who opted to start PrEP were cisgender men who have sex with men, one was a transgender man with male sex partners, and three were heterosexual women.

“Our patients on PrEP were primarily gay men,” Hare said. “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.”

Only one PrEP user reported injection drug use as a risk factor, and 15 said they had used PEP during the three months before starting PrEP. PrEP users were significantly more likely than those who decided against PrEP to have multiple sex partners (84% vs 69%, respectively), but PrEP users and PrEP-decliners were about equally likely to report having an HIV-positive partner (30% vs 25%, respectively).

The authors noted that based on data from the placebo arm of the PROUD PrEP trial in the UK, which had a similarly high rate of rectal STIs, they would have expected an HIV incidence as high as 8.9 per 100 person-years—or about 35 total infections—without effective PrEP.

New STIs, however, were common. A total of 187 PrEP users were diagnosed with at least one STI during follow-up, with 78 people diagnosed with multiple STIs for a total of 344 STI diagnoses made over the course of follow-up. Though not discussed in the current report, Hare’s team reported earlier this year that two HIV-negative men receiving PrEP at Kaiser had been newly infected with hepatitis C, with sex being their only apparent risk factor.

The researchers were not able to compare STI incidence between PrEP users and a matched control group of non-users, so the study cannot say whether PrEP use was associated with an increase in STIs.

About one in five PrEP users (143 people) completed a survey about changes in sexual behavior after six months on PrEP. Of these, 56% said their condom use was unchanged, 41% reported a decrease, and 3% reported an increase. In addition, 74% said their number of sexual partners stayed the same, 15% reported fewer, and 11% reported more partners.

“We observed a dramatic increase in PrEP use in a clinical practice setting, with no new HIV infections among PrEP users,” the researchers concluded. “This was despite high rates of STIs—rectal STIs in particular—and self-reported decreases in condom use in 41% of a subset of PrEP users.”

The STI rates in this study “reinforce that ongoing screening and treatment for STIs, including hepatitis C, remain an essential component of PrEP delivery,” the Kaiser team wrote. “Given that STIs are independently associated with HIV acquisition, the frequent STI screening in our PrEP program may have facilitated earlier diagnosis and treatment of these infections and thus contributed to the protective benefit of PrEP against HIV infection.”

“PrEP is not a silver bullet in HIV prevention, and it’s not appropriate for everyone,” Hare told BETA. “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 accompanying editorial, Kimberly Koester and San Francisco AIDS Foundation medical director Robert Grant, MD, both from the University of California, San Francisco, noted that the high number of STIs may in part be attributable to more frequent testing among PrEP users rather than changes in sexual behavior. Previous ethnographic research by the authors found that many men who have sex with men seek sexual health services, including PrEP, from community-based clinics as opposed to primary health care providers. They say the current study’s findings highlight the fact that Kaiser members also feel comfortable accessing PrEP through their regular health provider.

“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,” they explained.

The dramatic increase in PrEP uptake approximately a year after FDA approval “produced an expected and most desired outcome—no new HIV infections—among a population vulnerable to HIV,” Koester and Grant wrote. “Given the historical devastation wrought by HIV/AIDS within the city of San Francisco and elsewhere, this is tremendously good news…[and] demonstrates meaningful progress towards the goal of halting new infections.”

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