ABSTRACT
BACKGROUND: Unboosted atazanavir with raltegravir has been investigated at 300mg twice daily showing frequent hyperbilirubinemia and selection of resistance-associated mutations. OBJECTIVES: Atazanavir 200mg twice daily could increase tolerability and plasma exposure. STUDY DESIGN: Patients on atazanavir/raltegravir (200/400 twice daily), with self-reported adherence >95% and no concomitant interacting drugs were retrospectively evaluated. RESULTS: 102 patients [72.5% male, age 46.4 years (42-54), BMI 24kg/m2 (22-26)] were included. CD4+ T lymphocytes were 417 cell/µL (302-704) and 76 patients (74.5%) had HIV-RNA <50 copies/ml. After 123 weeks 18.6% patients showed virological failure and 3.9% discontinued for intolerance. Available genotypes showed selection of major integrase (7/10 patients) and protease resistance-associated mutations (5/13 patients). In patients switching with dyslipidemia (n=67) total, LDL cholesterol and triglycerides significantly decreased. Patients switching with eCRCL<60ml/min (n=27) had no significant changes while patients with eCRCL >60ml/min showed significant decrease (-9.8ml/min, p=0.003) at 96-weeks. Atazanavir and raltegravir trough concentrations were 321ng/mL (147-720) and 412ng/mL (225-695). Self-reported non-adherence (n=4) was significantly associated with virological failure (p=0.02); patients with virological success had borderline longer previous virological control (33 vs. 18 months, p=0.07). DISCUSSION: Switch to atazanavir/raltegravir was safe and well tolerated allowing optimal drugs' plasma exposure. However, a concerning rate (18.6%) failed with newly selected mutations and stopped ATV/RAL because of DDI and intolerance issues or were lost to follow-up. This regimen might be considered in selected patients, without history of protease inhibitors failure or HBV infection, showing optimal adherence and prolonged suppression.
