Tenofovir disoproxil fumarate with emtricitabine (TDF/FTC) (Truvada, Gilead Sciences, Inc) should remain the first choice for the vast majority of patients with a risk of HIV and prescribed pre-exposure prophylaxis (PrEP) compared with tenofovir alafenamide with emtricitabine (TAF/FTC) (Descovy, Gilead Sciences, Inc), according to a new study.

The study authors examined the available data on the safety, efficacy, and public health context for 2 PrEP medications: TDF/FTC and TAF/FTC. Robust data show the efficacy of TDF/FTC in all priority populations at risk for HIV, including gay and bisexual men, transgender women, people who inject drugs, and heterosexual people whose partners are living with HIV. In contrast, the only efficacy data for TAF/FTC come from the DISCOVER trial, which enrolled solely gay and bisexual men and a smaller number of transgender women, according to the press release.

“In the DISCOVER study, TDF/FTC was associated with small changes in renal and bone biomarkers, while TAF/FTC was linked to weight gain and changes in cholesterol. Given the available clinical evidence and public health context, TDF/FTC should remain the first choice for the vast majority of PrEP users,” lead study author Douglas Krakower, MD, said in a press release.

He added that there were no differences between the groups in clinical events or the number of people who had stopped the drug for safety reasons, suggesting that these small changes may not be clinically significant.

In October 2019, the FDA approved a second medication for use as HIV PrEP. Gilead Sciences, which manufactures the drugs, argued that TAF/FTC, the newer drug, is safer and more effective than the older drug. The study authors noted that TDF/FTC has been used for PrEP for more than 7 years, with ample evidence of its safety and efficacy.

The high cost of these medications, around $24,000 annually in the United States, has been a major barrier to PrEP use, according to the study authors.

The older PrEP medication, TDF/FTC, will be available as a generic as early as 2020, potentially reducing costs and increasing access. However, Gilead Sciences holds the exclusive rights to manufacture TAF/FTC until 2022 and has requested a patent extension to 2025. If the generic version of TDF/FTC is perceived to be less safe, the uptake of TAF/FTC would rise and may lead to cost ramifications.

“With the exorbitant cost of these drugs, there are huge public health and economic implications if most PrEP users begin to use the newer TAF/FTC pill rather than TDF/FTC for PrEP,” said Julia Marcus, PhD, senior author and assistant professor in the Department of Population Medicine at Harvard Pilgrim Health Care Institute and Harvard Medical School, in a press release.

Reference
Truvada Should Remain First Choice for HIV Prevention, Experts Say [press release]. EurekAlert website. Published January 13, 2020. https://eurekalert.org/pub_releases/2020-01/hphc-tsr010820.php. Accessed January 27, 2020.