Virologic failure in art naïve patients initiating on a dolutegravir or elvitegravir-based regimen

Background. Robust pharmacoeconomic modeling is dependent on high quality inputs, preferably from randomized clinical trials (RCT), but not all needed head to head comparisons occur in RCTs. We compared virologic outcomes in an antiretroviral (ART) naïve population initiating a dolutegravir (DTG) or elvitegravir (EVG)- based regimen using clinical trial-like criteria. Methods. ART-naive adults, initiating a DTG- or EVG-based regimen and meeting all study eligibility criteria (Figure 1) were identified in the OPERAR Observational Database, a collaboration of HIV caregivers following 100,000+ people living with HIV (PLWH) through electronic medical records. PLWH were followed from the date of first prescription until DTG- or EVG discontinuation, death, or study end (July 31, 2018). The primary outcome was verified (2 consecutive viral load (VL) ≥ 200 copies/ mL or 1 VL ≥ 200 copies + discontinuation) virologic failure (VF), defined as either failure to achieve suppression (<50 copies/mL) prior to 36 weeks or failure to maintain suppression once achieved. Survival analyses were conducted with Kaplan-Meier methods and multivariate Cox Proportional Hazards modeling. Results. A total of 1,688 (DTG) and 2,537 (EVG) met all eligibility criteria. Median (IQR) length of follow-up in the DTG users was 21 months (14-30), in the EVG users was 20 (14-32) months. Figure 2 characterizes baseline demographic/clinical characteristics. Figures 3 and 4 depict Kaplan-Meier curves and Cox model results, respectively. VF was experienced by 8.2% DTG and 10.9% EVG initiators at a rate (95% CI) per 1,000 person-years of 40.2 (33.8, 47.8) and 51.3 (45.3, 58.1), respectively. Younger age (18-25), being African American, having a baseline CD4 count ≥200, or having a government-based payer (ADAP, Ryan White, Medicaid, or Medicare) at baseline were associated with a significant (P < 0.05), increased hazard of VF. Initiating on DTG or initiating therapy with a lower baseline VL was associated with a significant, reduced hazard of VF. Compared with DTG, the adjusted hazard ratio for VF was 1.29 (95% CI: 1.02, 1.63) for EVG. Conclusion. Among ART-naive patients, DTG users were significantly less likely to experience virologic failure than EVG users after adjustment for important baseline covariates. (Figure Presented).