Multispecies Evaluation of a Long-Acting Tenofovir Alafenamide Subdermal Implant for HIV Prophylaxis

New HIV-1 infection rates far outpace the targets set by global health organizations, despite important progress in curbing the progression of the epidemic. Long-acting (LA) formulations delivering antiretroviral (ARV) agents for HIV-1 pre-exposure prophylaxis (PrEP) hold significant promise, potentially facilitating adherence due to reduced dosing frequency compared to oral regimens. We have developed a subdermal implant delivering the potent ARV drug tenofovir alafenamide that could provide protection from HIV-1 infection for 6 months, or longer. Implants from the same lot were investigated in mice and sheep for local safety and pharmacokinetics (PKs). Ours is the first report using these animal models to evaluate subdermal implants for HIV-1 PrEP. The devices appeared safe, and the plasma PKs as well as the drug and metabolite concentrations in dermal tissue adjacent to the implants were studied and contrasted in two models spanning the extremes of the body weight spectrum. Drug and drug metabolite concentrations in dermal tissue are key in assessing local exposure and any toxicity related to the active agent. Based on our analysis, both animal models were shown to hold significant promise in LA product development.

Nexplanon Subdermal Implant: Assessment of Sexual Profile, Metabolism, and Bleeding in a Cohort of Italian Women

Objectives. To evaluate the impact on metabolism, bleeding, and sexual function of Nexplanon, a subdermal implant. Study Design. We recruited women (n=101) receiving the Nexplanon implant at two university centers in Italy between 2011 and 2016 into this prospective, observational, multicenter research trial. Participants completed the Interview for Ratings of Sexual Function (IRSF) and the Female Sexual Function Index (FSFI) questionnaires before and 3 and 6 months after the implant was inserted. In addition, all blood parameters were assessed at these visits. All women were given a menstrual diary card and a pictorial blood assessment chart to record daily any vaginal bleeding. Results. The studied metabolic parameters remained in the normal range, showing no alarming modifications: minimal statistical reductions (in aspartate aminotransferase, alanine aminotransferase, total cholesterol, triglycerides, and activated partial thromboplastin time) and increases (in glucose and prothrombin activity) were observed. Changes in IRSF score over 6 months showed a significant increase in pleasure, personal initiative, orgasm, intensity of orgasm, and satisfaction, and a significant decrease in anxiety and discomfort. Mean Body Mass Index decreased, and the weekly frequency of sexual intercourse increased. Conclusions. Nexplanon showed not only a lower metabolic and bleeding impact, but also important positive effects on sexual function. It expands the range of possibilities for women, 38 and couples, in the modern concepts of sexual and reproductive wellbeing.