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No New HIV Infections Seen Among San Francisco Kaiser PrEP Users

No new HIV infections have occurred among more than 500 Kaiser Permanente San Francisco members using pre-exposure prophylaxis -- better known as PrEP -- but condom use appears to be declining among a subset of gay men, according to a small survey presented at a December 1 forum commemorating World AIDS Day.

"PrEP is provided for the purpose of preventing HIV infections, and we're seeing that hold true," said Bradley Hare, Kaiser San Francisco's director of HIV care and prevention.

Hare described preliminary findings from a survey of Kaiser members who started taking Gilead Sciences' Truvada (tenofovir/emtricitabine) combination pill to prevent HIV.

The U.S. Food and Drug Administration approved Truvada for PrEP in July 2012, based in part on data from the iPrEx trial of mostly gay and bisexual men. This trial showed that once-daily Truvada reduced the risk of HIV infection by 42% overall, rising to 92% among participants with blood drug levels indicating regular use. In an open-label extension of iPrEx, none of the men who took Truvada at least 4 times per week became infected. This past May, the U.S. Centers for Disease Control and Prevention (CDC) recommended that people at substantial risk for HIV infection should consider PrEP.

The Kaiser survey was only recently initiated and so far has received responses from approximately 90 members -- less than 20% of PrEP recipients -- mostly men who have sex with men. The survey is intended to help Kaiser providers learn more about their patients taking PrEP in an effort to provide better clinical care, Hare told HIVandHepatitis.com.

Such preliminary results presented at an informal forum normally would not be major news. But the AIDS Healthcare Foundation -- which has waged a media campaign against PrEP -- issued a press release on December 8 calling attention to an article in the San Francisco Business Times highlighting one number from Hare's presentation: 45% of survey respondents reported using condoms less often since they started PrEP.

"This Kaiser study confirms the fears of organizations like AHF that have expressed caution and skepticism about the wisdom of the community’s wholesale embrace -- as well as the CDC’s recommendation -- of the widespread scale up of PrEP," stated AHF president Michael Weinstein. "This study should serve as a warning and may one day be seen as the canary in the coal mine of unintended -- but predictable -- consequences of a poorly thought out public health strategy." 

Explaining the survey findings in more detail, Hare said that among the 90 people who chose to answer the survey -- a group that may not be representative of Kaiser's PrEP users overall -- half said their condom use had remained the same, 45% said it had decreased, and 5% said it had increased since they went on PrEP.

Hare emphasized that they do not have baseline data about how often respondents used condoms before starting PrEP, and there is no control group of men not using PrEP for comparison. However, the fact that the men chose to go on PrEP suggests they likely were already having sex without condoms at least some of the time.

"We don’t know if we took [condom use] from 100% to zero, or from 50% to 40%," Hare said. "With the extra protection provided by PrEP, some may have decided to forego condoms" -- including people in monogamous relationships with HIV-positive partners, he suggested.

The survey did ask about changes in the number of sex partners, and found that this did not increase. "It's not the case that people are having a lot of unprotected sex with a lot of new partners" after starting PrEP, Hare said.

PrEP clinical trials generally have not seen evidence of so-called "risk compensation" -- engaging in more risky behavior or reducing use of other prevention methods. But anecdotal reports in the gay community suggest that many men find dispensing with condoms to be one of the major benefits of PrEP.

"Is anyone actually surprised that once PrEP starts settling in as a safer sex strategy, some guys who use it are going to use condoms less?" asked PrEP advocate Gus Cairns from Aidsmap. "The important question is not whether they are using condoms less. It's are they protected from HIV better or worse than they were before they started PrEP?"

As Weinstein noted, PrEP critics fear that a reduction in condom use could lead to a rise in other sexually transmitted diseases.

"We are seeing a high numbers of STDs in people on PrEP," Hare acknowledged, but again he stressed that there is no control group of people not taking PrEP to use for comparison.

These STDs include the "usual suspects" syphilis, gonorrhea, and chlamydia, he said, but Kaiser providers have also seen two cases of acute hepatitis C in HIV-negative gay men who were not injections drug users. Sexually transmitted hepatitis C has been reported among HIV positive men over the past decade and a half, but it has been thought to be rare among HIV negative men.

While concern about STDs is well founded, the goal of PrEP is to prevent HIV, Hare emphasized.

"We've seen zero cases of HIV among more than 500 guys on PrEP," he said. "Behavior and STDs are important things to watch to be able to prescribe it responsibly, but PrEP is prescribed to prevent HIV, and it's working."

How Many Are on PrEP?

Another number from Hare's presentation stands out. The total number of people receiving PrEP at Kaiser is now just over 500. When Kaiser physician Jonathan Volk gave an overview of PrEP users at a San Francisco Department of Public Health community forum this past September, the number stood at just over 300 through July 2014, indicating a rapid rise in recent months.

However, Volk and Hare noted that about one-third of people who are referred to the program decide not to start PrEP for a variety of reasons, including cost and concern about side effects -- a worry generally not supported by evidence from clinical trials.

Speaking at a San Francisco Board of Supervisor's hearing in September, iPrEx principle investigator Robert Grant estimated that approximately 800 people in San Francisco were using PrEP, and that Kaiser is the largest PrEP program in the U.S.

Nationwide, a Gilead analysis of prescription data from 55% of U.S. pharmacies, presented at the HIV Drug Therapy conference last month in Glasgow, found that a total of 3253 people had been prescribed PrEP since January 2012 -- including 880 prescriptions during the last quarter of 2013 and the first quarter of 2014 alone. These totals do not include people accessing PrEP through Medicaid, clinical trials, or demonstration projects.

Compared with an earlier analysis Gilead scientists presented in 2013, the proportion of PrEP users who were women fell from 54% to 23%. This change reflects an upsurge in interest in PrEP among gay and bisexual men -- an increase some prevention advocates attribute in part to AHF's publicity. The rise also coincides with the CDC's PrEP recommendation in May, followed in July by the World Health Organization recommending PrEP as an option for at-risk gay men.

Hare expects that the surge in interest in PrEP at Kaiser is likely to continue. "By the time we talk again, it will probably be 600 people," he predicted.

12/10/14