The effect of antacid and mineral supplements on bictegravir pharmacokinetics: results from a Phase 1, open-label, drug–drug interaction study
Year: 2025
Type: article
Abstract: The mechanism of action of integrase strand transfer inhibitors involves binding to magnesium ions in the active site of the HIV integrase enzyme, making them susceptible to chelation-type drug-drug interactions with metal cation-containing medications. This study evaluated the potential of metal cation-containing antacids and mineral supplements to impact bictegravir (BIC) exposure and assessed alternative approaches for combined use. This was an open-label, single-dose, Phase 1 study in adult participants without HIV. The pharmacokinetics and safety of BIC (administered as part of a single-tablet combination with emtricitabine [F] and tenofovir alafenamide [TAF; B/F/TAF]) were assessed when co-administered with maximum-strength aluminum/magnesium-containing antacid (referred to as "aluminum/magnesium-containing antacid"), calcium carbonate, or ferrous fumarate under fasted and fed conditions, and administered 2 hours before or after the antacid. Pharmacokinetic parameters were compared using analysis of variance to calculate geometric least-squares mean ratios and 90% confidence intervals. Forty-two participants were enrolled. BIC exposure (area under the plasma concentration-time curve extrapolated to infinity) was reduced by 79%, 33%, and 63%, respectively, when co-administered with aluminum/magnesium-containing antacid, calcium carbonate, and ferrous fumarate under fasted conditions. Co-administration of B/F/TAF with calcium carbonate or ferrous fumarate with a meal and administration of B/F/TAF 2 hours before the antacid reduced the impact of the interactions. B/F/TAF was well tolerated alone or in combination with metal cation-containing medications. Co-administration of BIC and calcium/iron-containing supplements with a meal and administration of BIC 2 hours or more before aluminum/magnesium-containing antacids are some of the effective strategies to mitigate chelation effects on BIC exposure.This study was registered at NCT05502341/NCT06333808.
DOI: 10.1128/aac.00781-25
Institution: Gilead Sciences (United States)
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
Funder: Gilead Sciences
OpenAlex ID: W4416792232