Monday, September 7, 2015

HIV Medicine protects all participants in new study

A new study following 657 people who took the HIV prevention drug Truvada for 2.5 years has found that 100 percent of them remain HIV-free - even those in high-risk environments. The pill, which has to be taken every day without fail, has been on the market in the US since 2012, and trials are currently underway all over the world, across Africa, Asia, South America, and in several Australian states. 

But despite promising results, researchers are hesitant to overstate the potential of the drug in combating the spread of HIV because of how fast its efficacy falls when a pill is skipped, and the persistent stigma that’s followed its use in the US.

Researchers following over 600 people who took an HIV prevention pill for more than two years have found that 100% of them remained free from the virus even in high-risk environments.

The study conducted at Kaiser Permanente in San Francisco involved more than 600 high-risk individuals, most of whom were men who have sex with men. These individuals were healthy at the time of enrollment and were put on a daily regimen of a blue pill called Truvada as a pre-exposure prophylaxis (PrEP).

The study is "the first to extend the understanding of the use of PrEP in a real-world setting and suggests that the treatment may prevent new HIV infections even in a high-risk setting," said lead author Jonathan Volk, a physician and epidemiologist at Kaiser Permanente San Francisco Medical Centre.

In the study, 100% of the participants remained HIV-free. Not a single person in the study became infected while on the drug during the study period that included 2.5 years of observation, the Washington Post reported.

No individuals taking preexposure prophylaxis (PrEP) were diagnosed with HIV during 388 person-years of follow-up in a study published online September 1 in Clinical Infectious Diseases.

The researchers analyzed data from 801 individuals with at least one intake visit in the Kaiser Permanente San Francisco system who had been referred for PrEP evaluation between July 2012 — when the US Food and Drug Administration approved daily oral emtricitabine/tenofovir disoproxil fumarate (Truvada, Gilead) as PrEP — and February 2015.

Of these, 82% (657 individuals; average age, 37 years) began taking PrEP, continuing for an average of 7.2 months. Nearly all were men having sex with men; the exceptions were 3 heterosexual women and 1 transgender man who had sex with men.

Of these, 82% (657 individuals; average age, 37 years) began taking PrEP, continuing for an average of 7.2 months. Nearly all were men having sex with men; the exceptions were 3 heterosexual women and 1 transgender man who had sex with men.

Compared with the 18% who did not initiate PrEP, those who started it were no more likely to have an HIV-infected sex partner (30% PrEP vs 25% non-PrEP; P = .18). However, 84% of PrEP users reported multiple sex partners compared with 69% of those not taking PrEP (P < .001).

More than a third (35%) of those who did not start taking PrEP said they didn't because they had a low risk for HIV. Among other leading reasons for not taking it were concern about the cost (15%), lack of desire to complete the required follow-up (10%), and preference for postexposure prophylaxis (6.3%). Only a small percentage were concerned about adverse effects (2.8%) or increasing their sexual risk behavior (1.4%).

Just over a quarter (28.4%) of those who started PrEP were diagnosed with an STI during follow-up, and 11.9% had multiple STIs. By 12 months after starting PrEP, 50% of the users had any STI (95% confidence interval [CI], 43% - 56%), including 28% with gonorrhea (95% CI, 23% - 34%) and 5.5% with syphilis (95% CI, 3.3% - 9.1%). A third (33%) had a rectal STI (95% CI, 27% - 39%), and a third (33%) had chlamydia (95% CI, 27% - 39%). None were diagnosed with HIV during the entire follow-up (upper limit of one-sided 97.5% CI, 1.0%).

Among 143 persons surveyed about behavior changes after 6 months of taking PrEP, 74% said their number of sexual partners had not changed, 15% said it had decreased, and 11% said it had increased. Just over half (56%) did not change their condom use, 41% used condoms less often, and 3% used them more.

In an accompanying commentary, Kimberly A. Koester, MA, and Robert M. Grant, MD, MPH, from the University of California, San Francisco, commend the study authors "for creating a clinical environment conducive for gay and other men who have sex with men to feel comfortable enough to use their specialized PrEP program."

They also note the difficulty of interpreting the STI data.

"The increased [frequency] of STI testing offered during PrEP services affords more timely diagnosis and treatment of STIs, and high rates of diagnosis may reflect greater diagnostic yield rather than changes in sexual behavior," Koester and Grant write. "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 write.

Yet they also state that the time has come "for a vigorous conversation about sexually transmitted infections, too long eclipsed by fear of HIV infection."

"Ideally," they write, "the public health response to the possibility of rising incidence of STIs in the context of decreased or no new HIV infections would be framed in relative terms and therefore considered to be a good problem to have."

The research was funded by Kaiser Permanente Northern California. One author has received research grants from Merck. The remaining authors have disclosed no relevant financial relationships.

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