Antiretroviral drugs require patients to adhere to a strict dosing regimen, but as with other diseases patients tend to slack off, often paying a high price. Researchers at the Oak Crest Institute of Science in Pasadena, California have developed a small implant that can deliver tenofovir alafenamide fumarate, a prodrug developed by Gilead Sciences to help treat and prevent HIV infection, in a controlled manner.
The device looks like the now commonly available subdermal contraception implants and releases its cargo evenly over a period of 40 days. It was tested on dogs to see whether there are any side effects, the researchers not detecting any adverse events in the study. It’s now hoped that the technology may soon be made available for at-risk populations, as the drug is looking very promising as a prophylaxis for HIV, as well as for treatment of infected patients.
Some details from the study in journal Antimicrobial Agents and Chemotherapy
A candidate device delivering TAF at 0.92 mg d-1 in vitro was evaluated in beagle dogs over 40 d for pharmacokinetics and preliminary safety. No adverse events related to treatment with the test article were noted during the course of the study and no significant, unusual abnormalities were observed. The implant maintained a low systemic exposure to TAF (median 0.85 ng ml-1, IQR 0.60-1.50 ng ml-1) and tenofovir (TFV, median 15.0 ng ml-1, IQR 8.8-23.3 ng ml-1), the product of in vivoTAF hydrolysis. High concentrations (median 512 fmol/106 cells over the first 35 days) of the pharmacologically active metabolite, TFV diphosphate, were observed in peripheral blood mononuclear cells, levels over 30 times higher than those associated with HIV-1 PrEP efficacy in humans.
Study in Antimicrobial Agents and Chemotherapy: Pharmacokinetics of Long-acting Tenofovir Alafenamide (GS-7340) Subdermal Implant for HIV Prophylaxis…
Source: Oak Crest Institute of Science…