To dose-adjust or not to dose-adjust: lamivudine dose in kidney impairment.

OBJECTIVES: To assess the risk of adverse diagnoses and laboratory abnormalities associated with a 300 or 150 mg daily dose of lamivudine (3TC) initiated by people with HIV (PWH) with an estimated glomerular filtration rate (eGFR) between at least 30 and 49 ml/min per 1.73 m2 or less. DESIGN: Longitudinal study based on electronic health records of 539 PWH with eGFR between at least 30 and 49 ml/min per 1.73 m2 or less from the Observational Pharmaco-Epidemiology Research and Analysis (OPERA) cohort. METHODS: Common unintended effects of 3TC were evaluated as composite outcomes. We estimated the incidence (univariate Poisson regression) and association between dose and incident composite outcomes (multivariate Poisson regression) among PWH without the relevant diagnoses or laboratory abnormalities at 3TC initiation. RESULTS: PWH initiating 150 mg 3TC had higher HIV RNA, lower eGFR, and more comorbidities than those initiating 300 mg 3TC. The prevalence of relevant diagnoses and laboratory abnormalities was similar in both groups. The most common lab abnormality was low hemoglobin. There was no statistically significant difference in incident adverse diagnoses/severe lab abnormalities with 300 mg versus 150 mg [incidence rate ratio (IRR): 1.51; 95% confidence interval (CI) 0.59--3.92). However, a statistically significant association was observed when gastrointestinal symptoms/moderate lab abnormalities were included in the outcome (IRR: 3.07, 95% CI 1.12--8.40). CONCLUSION: As 3TC is a well tolerated drug with a wide therapeutic window, dose adjustment may be unnecessary among PWH with eGFR between at least 30 and 49 ml/min per 1.73 m2 or less. Clinical judgement is key when weighing the risks and benefits of 3TC dose adjustment for PWH experiencing gastrointestinal symptoms or moderate lab abnormalities.

Response by gender of HIV-1-infected subjects treated with abacavir/lamivudine plus atazanavir, with or without ritonavir, for 144 weeks.

PURPOSE: The 144-week results of the open-label, multicenter Atazanavir/Ritonavir Induction with Epzicom Study (ARIES) were stratified by gender to compare treatment responses. METHODS: A total of 369 HIV-infected, antiretroviral-naïve subjects receiving once-daily abacavir/lamivudine + atazanavir/ritonavir (ATV/r) whose HIV-1 RNA was <50 copies/mL by week 30 were randomized 1:1 at week 36 to maintain or discontinue ritonavir for 108 subsequent weeks. Between- and within-treatment gender-related efficacy and safety differences were analyzed. RESULTS: Subjects were 85% male; 64% white; and had a mean age of 39 years, baseline median HIV-1 RNA of 114,815 copies/mL, and median CD4+ cell count of 198 cells/mm3. Gender (ATV [n=189]: 29 females/160 males; ATV/r [n=180]: 25 females/155 males) and most other demographics were similar between groups; more females than males were black (65% vs 25%) and fewer females had baseline HIV-1 RNA ≥100,000 copies/mL (41% vs 58%). At week 144, no significant differences between genders were observed in proportion maintaining HIV-1 RNA <50 copies/mL (ATV, 79% vs 77%; ATV/r, 60% vs 75%) or <400 copies/mL (ATV, 83% vs 84%; ATV/r, 68% vs 82%) (intent-to-treat-exposed: time to loss of virologic response analysis); median CD4+ change from baseline (ATV, +365 vs +300 cells/mm3; ATV/r, +344 vs +301 cells/mm3); proportion with treatment-related grade 2-4 adverse events (baseline to week 144: ATV, 41% vs 31%; ATV/r, 36% vs 43%; weeks 36 to 144: ATV, 14% vs 13%; ATV/r, 24% vs 23%); or proportion developing fasting lipid changes. Female and male virologic failure rates (ATV, 0 vs 5; ATV/r, 2 vs 4) and proportions completing the study were similar during the extension phase. Primary withdrawal reasons were loss to follow-up and pregnancy for females and loss to follow-up and other for males. CONCLUSION: Over 144 weeks, no significant gender differences were observed in efficacy, safety, or fasting lipid changes with abacavir/lamivudine +ATV or abacavir/lamivudine +ATV/r.