ABSTRACT
Switching from oral antiretroviral treatment to intramuscular (IM) cabotegravir (CAB) + rilpivirine (RPV) has an optional oral lead-in to ensure tolerability. The British HIV Association guidelines advise against directly switching from oral antiretroviral (ART) combinations containing strong/moderate cytochrome inducers like efavirenz (EFV) to IM CAB + RPV. EFV has a prolonged elimination half-life, leading to a residual induction of UGT1A1 and CYP3A4 after discontinuation. These enzymes are responsible for CAB and RPV metabolism and their induction might lead to sub-optimal concentrations of CAB and RPV, risking drug resistance. When switching from EFV to oral CAB + RPV, the ATLAS and ATLAS 2M studies showed reduced RPV concentrations but with maintained viral suppression during the oral lead-in and subsequent long-acting injectable (LAI) phases. Also, a recent pharmacokinetic modelling study indicated reduced RPV concentrations, without viral implication, when switching from EFV to IM CAB + RPV. However, there are limited real-world data on direct switching from EFV-based therapy to long-acting IM CAB + RPV. We describe a case where oral intake was impossible in a critical care scenario, switching from emitricitabine/tenofovir-DF (FTC/TDF) 200/245 mg + 600 mg EFV to IM CAB + RPV for treatment optimisation.
Subject(s)
Anti-Retroviral Agents , Benzoxazines , Cyclopropanes , Diketopiperazines , Pyridones , Rilpivirine , Humans , Rilpivirine/therapeutic use , Alkynes , TenofovirABSTRACT
A middle-aged Caucasian man living with HIV, clinically stable (viral load <20 copies/mL) on injectable antiretroviral cabotegravir plus rilpivirine every 2 months presented with a 6-month history of bilateral enlargement of the breasts associated with pain. His hormonal profile was normal, and no other underlying cause was identified. He was diagnosed with idiopathic gynecomastia. Tamoxifen is an anti-oestrogen recommended for gynecomastia and has been described in people living with HIV but can potentially induce the activity of cytochrome P450 3A4 (CYP3A4), reducing rilpivirine concentrations, which consequently may cause virological failure and resistance. This is the same for other antiretroviral agents majorly induced by CYP3A4. To date, there have been no reported cases of using anastrozole as a treatment for gynecomastia in people living with HIV or of its co-administration with antiretroviral. We describe the use of an aromatase inhibitor instead of tamoxifen in a person living with HIV, diagnosed with gynecomastia.
