DURBAN, SOUTH AFRICA – The number of Americans using oral emtricitabine/tenofovir (Truvada) to prevent HIV infection jumped by 738% during a recent 3-year period since the drug’s 2012 marketing approval. However, uptake in certain at-risk populations leaves much room for improvement, Scott McCallister, MD, said at the 21st International AIDS Conference.
“While there are encouraging signs in using Truvada for pre-exposure prophylaxis across the country as a whole, there are certainly barriers that must be addressed in women, those under age 25, and in certain regions of the U.S. where lifetime risk of HIV acquisition is high,” said Dr. McCallister, senior director for clinical research at Gilead Sciences in Foster City, Calif.
Dr. Scott McCallister
He presented key findings from a national survey of 80% of retail pharmacies that showed that more than three-quarters of the 79,684 individuals who started on emtricitabine/tenofovir for HIV chemoprophylaxis during the fourth quarter of 2012 through the end of 2015 were men. Just 11% of the men and 28% of women taking the drug for pre-exposure prophylaxis (PrEP) were under age 25, a particularly high-risk group.
Fifty-one percent of all patients on emtricitabine/tenofovir for PrEP resided in five states: Texas, New York, Florida, Illinois, and California. Yet that doesn’t reflect the distribution of the HIV epidemic. A 2016 Centers for Disease and Prevention report concluded that the highest lifetime risk of HIV infection occurs in eight southeastern states and the District of Columbia, as well as Texas and New York.
“Some of the states with the highest lifetime risks of HIV diagnosis are lagging behind and have low numbers for Truvada for PrEP,” Dr. McCallister observed.
The Centers for Disease Control and Prevention estimates that while the lifetime risk of HIV is 1 in 99 in the United States overall, it’s 1 in 48 among black or Hispanic men, 1 in 2 for black men who have sex with men, and 1 in 4 for Hispanic MSM. Moreover, the CDC has also reported that 44% of all new HIV diagnoses occur in African Americans. And while Dr. McCallister said it’s difficult to analyze race/ethnicity in the Gilead survey because the data were de-identified, it’s his impression from other studies and talking with clinicians that PrEP users are disproportionately white.
Asked why prescribing of emtricitabine/tenofovir to date for PrEP in men far outpaces that for women, Dr. McCallister offered a theory: “Based on conversations I’ve had with community-based physicians who are avid prescribers, I think it’s a matter of men having a greater comfort level in terms of using PrEP because their clinicians and the MSM communities are more knowledgeable about PrEP. Perhaps there are fewer touch points for women to see knowledgeable clinicians. They are probably most often going to an ob.gyn. or a primary care physician who may have slightly less knowledge of PrEP than the HIV specialists or sexual health clinics where many MSMs are going.”
He noted that in addition to the randomized trial evidence of safety and efficacy that won Food and Drug Administration approval of emtricitabine/tenofovir for HIV PrEP, the real-world experience accrued in 32 demonstration projects with a total of more than 7,000 person-years of follow-up showed an HIV seroconversion rate of 0.95% per year in patients on the daily oral medication.
Dr. McCallister is an employee of Gilead Sciences, which sponsored the national PrEP survey and markets emtricitabine/tenofovir.