Integrating dolutegravir into the national Tanzanian formulary: treatment uptake and virologic outcomes from a longitudinal study

Abstract

INTRODUCTION: The transition to dolutegravir (DTG) antiretroviral therapy (ART) has now become the preferred first-line treatment for people living with HIV (PLHIV) in many low- and middle-income countries. We report virologic outcomes among adolescents and adults who transitioned to DTG-based therapy and those initiated on DTG based ART in Dar es Salaam, Tanzania. METHODS: We performed retrospective and prospective data abstraction from an electronic care and treatment database at Muhimbili National Hospital (MNH) for participants aged 15 years and above. Eligible participants were treatment-naïve PLHIV initiating tenofovir-lamivudine-efavirenz (TLE) or tenofovir-lamivudine-dolutegravir (TLD) and treatment-experienced patients with a transition opportunity between March 2019 and August 2019. We assessed baseline differences in patient characteristics before and after weighting with inverse probability weights using the chi-square and Mann-Whitney tests for categorical and continuous variables, respectively. A multivariate robust Poisson regression model was used to evaluate the probability of viral suppression (VS) for participants who transitioned to TLD. Differences in VS rate at follow-up between participants initiating TLE and TLD were assessed using the log-rank test and Kaplan-Meier survival curves. RESULTS: A total of 1,073 participants were included, 284 were initiated on ART, and 789 with a transition opportunity, with a median age of 39 years (IQR 33, 46), and 905 females (83.9%). Participants who transitioned their ART regimen to TLD had a higher rate of achieving VS compared to those who remained on TLE (92.4% versus 84.4%, respectively; p = 0.005). Notably, participants who remained on TLE had a higher proportion of high viral load (VL ≥ 1000 copies/ml), 15.6%, compared to 7.6% of those who transitioned to TLD. In multivariable analysis, participants who were initiated on TLD as their first line ART had 3-fold higher likelihood of VS compared to those new to TLE (adjusted hazard ratio 3.07, 95% CI 1.88-5.03 (p-value < 0.001). Other factors were not significantly associated with VS. CONCLUSION: VS was higher in participants who transitioned to TLD and those initiated on TLD. Long-term follow-up of treatment-experienced, Integrase inhibitors (INSTI)-naïve and PLHIV who transitioned to the TLD regimen (with unknown viral loads or NRTI resistance) is recommended.