Introduction: Unboosted atazanavir (ATV) including regimens have been investigated as a ritonavir-sparing simplification strategy. No data are available on removal of one NRTI in subjects effectively treated with unboosted atazanavir+2NRTIs. We present the 48-week virological efficacy and safety of unboosted atazanavir plus lamivudine (3TC) or emtricitabine (FTC) (lamivudine/emtricitabine/Reyataz(©), LAREY Study).
Materials and methods: Single arm, prospective, pilot study on HIV-treated patients, HBsAg negative, with HIV-RNA<50 cps/mL since at least 2 years, who switched from ATV+2NRTIs to ATV 400 mg QD +3TC or FTC. Virological failure was defined as 2 consecutive values of HIV-RNA>50 cps/ml; viral blip was defined as a single HIV-RNA value>50 cps/ml not subsequently confirmed. RESULTS as median (IQR). Changes between baseline (BL) and week 48 assessed by the Wilcoxon signed rank test.
Results: Forty patients enrolled: 75% males, 51 (47-54) years, 14% HCV co-infected, infected with HIV since 16 (9-21) years, on antiretroviral therapy since 13 (5-16) years, with a nadir CD4+ of 254 (157-307) cells/mm(3), virologically suppressed since 4.2 (2.2-5.4) years; 53 patients switched from a tenofovir (TDF)-based regimens; ATV was associated with 3TC in 83% patients. No virological failures or discontinuations were observed; three patients had a single viral blip in the range 50-250 copies/mL; CD4+ increased from 610 (518-829) cells/mm(3) at BL to 697 (579-858) cells/mm(3) at week 48 [48-week change: 39 (-63/+160) cells/mm(3) p=0.081]. Three clinical events were observed (one herpes zoster, one pneumonia, one syphilis) in absence of renal lithiasis, AIDS-defining or drug-related events or death. Overall, significant 48-week amelioration of ALP [BL: 83 (71-107) mg/dL; 48-week change: -15 (-27/-8) mg/dL p<0.0001] and CKD-EPI [BL: 100 (86-108) ml/min/1.73 m(2); 48-week change: 1.5 (-3/+8) ml/min/1.73 m(2), p=0.042] were observed. Patients switching from TDF (Table 1) significantly improved CD4+, lymphocytes, hepatic profile, renal profile and ALP; these patients had also a modest but significant decrease in haemoglobin.
Conclusions: Switch from an unboosted atazanavir-based regimen to ATV+3TC or FTC regimen was effective and safe in this small sample, supporting the hypothesis of a potential two-steps de-intensification (removal of ritonavir and removal of one NRTI) in patients on long-lasting virological suppression.