Strong inhibitors of CYP3A4 and P-gp together (e.g. cobicistat) do not result in a clinically meaningful increase in lenacapavir exposures. Co-administration of lenacapavir (300 mg single oral dose) and cobicistat (150 mg once daily) increased lenacapavir AUC and Cmax by 128% and 110%. Co-administration of lenacapavir (600 mg single dose following a loading regimen of 600 mg twice daily for 2 days) and tenofovir alafenamide (25 mg) increased AUC and Cmax of tenofovir alafenamide by 32% and 24%; tenofovir AUC and Cmax increased by 47% and 23%. No dose adjustment of lenacapavir or tenofovir alafenamide is required. If Sunlenca is discontinued, residual concentrations of lenacapavir may remain in the systemic circulation of patients for prolonged periods. These concentrations are not expected to affect the exposures of other antiretroviral agents that are initiated after discontinuation of Sunlenca.

Based on drug interaction studies conducted with lenacapavir, no clinically significant drug interactions have been observed with cobicistat and tenofovir alafenamide. Coadministration of lenacapavir (300 mg single oral dose) and cobicistat (150 mg once daily) increased lenacapavir Cmax and AUC by 110% and 128%. Coadministration of lenacapavir (600 mg single dose following a loading regimen of 600 mg twice daily for 2 days) and tenofovir alafenamide (25 mg) increased tenofovir alafenamide Cmax and AUC by 24% and 32%; tenofovir Cmax and AUC increased by 23% and 47%.