A daily pill containing the newer formulation of tenofovir in combination with emtricitabine (Descovy) had a comparable protective effect to the existing daily pill which contains the older tenofovir and emtricitabine (Truvada), Dr Brad Hare of the Kaiser Permanente San Francisco Medical Center told the Conference on Retroviruses and Opportunistic Infections (CROI 2019) in Seattle today. As expected, the newer formulation had better bone and kidney safety outcomes.
The only licensed medication for oral pre-exposure prophylaxis (PrEP) is a combination of tenofovir disoproxil fumarate (TDF) and emtricitabine, marketed by Gilead Sciences as Truvada, but also available in many countries as a generic product. TDF is highly efficacious and generally well tolerated, but is associated with kidney and bone abnormalities in a minority of people. It is not recommended for individuals with existing kidney problems.
Gilead has developed a new formulation, tenofovir alafenamide (TAF). It achieves high concentrations in tissues, but blood concentrations are typically 90% lower than TDF, therefore reducing the risk of bone and kidney problems. TAF is included in several combination pills used for antiretroviral therapy, including a dual pill of TAF and emtricitabine, marketed as Descovy.
Whereas inexpensive TDF/emtricitabine products are available from generic manufacturers in many markets, TAF/emtricitabine (Descovy) is a new product exclusive to Gilead Sciences that is protected by patent.
In HIV treatment, TAF-based regimens have similar high virologic suppression rates and improved renal and bone safety as compared to TDF-based regimens. However, the efficacy and safety of TAF-based PrEP had not been tested until now.