Pharmacokinetics of the HIV integrase inhibitor S/GSK1349572 co-administered with acid-reducing agents and multivitamins in healthy volunteers

Objectives: To evaluate the effect of pH-altering agents on S/GSK1349572 exposure in healthy subjects. Methods: S/GSK1349572 is an unboosted, once-daily, next-generation HIV integrase inhibitor. In the first study, 16 subjects received four single-dose treatments: (i) S/GSK1349572 50 mg; (ii) S/GSK1349572 50 mg with a multivitamin (MVI; One A Day Maximum); (iii) S/GSK1349572 50 mg with a liquid antacid (Maalox Advanced Maximum Strength); and (iv) S/GSK1349572 50 mg 2 h before an antacid. In the second study, 12 subjects received a single dose of S/GSK1349572 alone and on day 5 of omeprazole. Results: All treatments were well tolerated. MVI co-administration modestly decreased S/GSK1349572 AUC by 33%. Concurrent antacid co-administration reduced S/GSK1349572 AUC by 74% and staggered antacid dosing significantly diminished this interaction, with a reduction in S/GSK1349572 AUC of 26%. Omeprazole did not significantly affect S/GSK1349572 exposure. Conclusions: S/GSK1349572 can be taken with proton pump inhibitors and MVIs without dose adjustment but should be administered 2 h before or 6 h after antacids.