Coadministration has not been studied but based on metabolism and clearance a clinically significant interaction is unlikely. Pemetrexed is not appreciably metabolised and is primarily eliminated unchanged renally (70-90% recovered in 24 hours). Darunavir/cobicistat is metabolized by CYP3A4. Pemetrexed is not expected to affect drugs metabolised by CYP3A4. Pemetrexed is a substrate of OAT3, but emtricitabine and tenofovir derived from tenofovir alafenamide are eliminated by other renal transporters.