Clinical outcomes associated with concomitant use of atazanavir and proton pump inhibitors.

Background: Pharmacokinetic studies have shown that the concomitant use of atazanavir and proton pump inhibitors (PPIs) decreases atazanavir plasma concentrations. Data describing clinical outcomes associated with this drug interaction are limited.
Objective: To describe the clinical outcomes, in terms of viral load (VL) suppression, associated with the concurrent use of ritonavir-boosted or unboosted atazanavir and PPIs.
Methods: A retrospective chart review of 301 HIV-positive adults attending an Ohio infectious diseases clinic was performed to identify patients prescribed atazanavir, with or without ritonavir, and a PPI. The primary outcome was achievement/maintenance of VL less than 400 copies/mL for 2 or more months during concomitant atazanavir and PPI therapies. Data collected included VL and CD4+ cell count at initiation of coadministered atazanavir and PPIs, genotype/phenotype, prior protease inhibitor experience, length of concurrent atazanavir/PPI therapy, and adherence.
Results: Twelve patients met inclusion criteria. PPIs and dosing regimens varied among subjects. Five of the subjects had a VL less than 400 copies/mL at initiation of atazanavir, with or without ritonavir, which was maintained during concurrent atazanavir and PPI therapy. Four additional subjects initiated protease inhibitor treatment with a VL greater than 400 copies/mL and achieved an undetectable VL while on concurrent PPI therapy. Duration of concurrent therapy ranged from 4 to 23 months in these 9 subjects. Of the 3 patients not maintaining a VL less than 400 copies/mL, 1 achieved that level at 4 months, and all 3 of these subjects showed atazanavir susceptibility during therapy per genotype resistance testing. Subsequently, decreased atazanavir susceptibility was reported in 1 of the 3 patients after 18 months of therapy. Patients not achieving an undetectable VL had known adherence issues.
Conclusions: In this case series, 9 of 12 subjects achieved successful virologic outcomes while receiving concurrent atazanavir and PPIs in a real-world environment. In our experience, the interaction between atazanavir and once-daily PPIs is not clinically significant for adherent patients. Concurrent use of these medications could be considered in patients with limited treatment options.