A randomized pilot study of tenofovir/emtricitabine (TDF/FTC) + boosted atazanavir (ATV/r) vs. raltegravir (RAL BID) + ATV/r vs. RAL BID + ATV BID

Abstract

Patients virologically suppressed on TDF/FTC + ATV/r may require alternative regimens that maintain suppression while addressing some drug‐related side effects. We explored two alternative regimens that replace RTV and/or TDF/FTC. This open‐label exploratory pilot trial enrolled 43 patients on TDF/FTC + ATV/r. Subjects were randomized to one of three arms. Arm 1 (n=15) replaced TDF/FTC with RAL 400 mg BID while continuing ATV/r. Arm 2 (n=14) made two changes: TDF/FTC was stopped and RAL BID was used instead; ritonavir was stopped and ATV 300 mg BID was used. Arm CTL (n=14) continued the baseline (BL) regimen. The week 48 final endpoint is summarized. The primary endpoint was maintaining virologic suppression (<40 c/mL); secondary endpoints compared safety measures. Overall mean age was 46, with 74% Caucasian, 21% black race and 12% female; similar characteristics noted across arms. Through week 48, all but two patients maintained virologic suppression; both virologic failures (>200 c/mL on two consecutive tests) were on arm 2; both reported adherence problems and no resistance mutations were detected. Overall CD4 counts were 534/mm3 at BL and 555/mm3 at week 48. There was a significant CD4 cell count difference favoring CTL (+52/mm3) vs. arm 2 (−14/mm3), p=0.03. No significant differences across arms were noted in lipid fractions or other lab tests. There were no clinically significant EKG changes across arms. Among AEs of interest through week 48, there were more neurologic AEs on arm 1 (n=7) and 2 (n=6) vs. CTL (n=1), and more musculoskeletal events noted on arm 2 (n=7) vs. arm 1 (n=3) and CTL (n=1). Quality of life was measured with a self‐assessment Likert scale. Scores were similar across arms despite the BID dosing in two arms. Self‐reported adherence using 3‐day recall was>95% in all three arms at both baseline and week 48. In this randomized pilot study, two of the three arms maintained virologic suppression in all subjects; there were two virologic rebounds in arm 2. No resistance mutations were detected in either, and adherence issues were noted for both subjects. We also noted that the CD4 cell change was significantly less on arm 2, and there were more neurologic and musculoskeletal AEs on arm 2 vs. CTL. In this study, the use of ATV/r with either TDF/FTC or RAL was successful over 48 weeks, but unboosted BID ATV 300 mg+BID RAL 400 mg as an alternative in virologically suppressed patients should be used with caution.