Coadministration has not been studied. Idelalisib is metabolised primarily by aldehyde oxidase, and to a lesser extent by CYP3A4 and UGT1A4. Maraviroc is metabolized by CYP3A4 and does not inhibit or induce CYP enzymes. The primary metabolite of idelalisib, GS-563117, is a strong CYP3A4 inhibitor. The European product label for maraviroc recommends when coadministering potent CYP3A4 inhibitors and maraviroc to patients with impaired renal function (creatinine clearance less than 80 ml/min), maraviroc should be reduced to 150 mg once daily. The US Prescribing Information recommends 150 mg twice daily for patients with creatinine clearance of 30-80 ml/min and contraindicates in patients with creatinine clearance less than 30 ml/min or on haemodialysis.