Background and Importance Persistency can provide information on the comparative effectiveness, durability and tolerability in real-world patient populations.

Little is known about comparative persistence of dolutegravir/lamivudine (DTG/3TC) and bictegravir/emtricitabine/tenofovir-alafenamide (BIC/FTC/TAF), two preferred antiretroviral treatments in our country.

Aim and Objectives To compare persistence between two preferred antiretroviral therapies and analyse reasons for discontinuation.

Material and Methods We conducted a retrospective, non-interventional, longitudinal study. All HIV patients over 18 years treated with DTG/3TC or BIC/FTC/TAF in our centre were included.

Persistence was defined as the duration of time from initiation to discontinuation of therapy (last dispensing or end of the study in March 2022). Persistence was also calculated as a dichotomous variable at the conclusion of the first year of therapy. Permissible gap (days between two prescription fills exceeding the allowable refill period) was 90 days.

Covariates collected from medical record were: age, gender, viral load (VL), CD4 count, number of previous antiretroviral medications, Charlson comorbidity index and Medication Possession Ratio (MPR).

Persistence after first year was compared using the χ² test. Kaplan-Meier survival analysis was performed and differences were evaluated using the log-rank test. Adjusted risk of discontinuation was assessed with Cox Proportional Hazard models. Significance level was 0.05.

Results Three hundred and sixty-two patients were included, 79.2% were male. 5.2% were naive. Age (mean ± SD) was 47 ± 12 years. 91.2% had VL<200 copies and 10.1% CD4<200/ml. Number of previous treatments was 3.5 ± 2.6. MPR was 95.4 ± 11.1 Charlson comorbidity index was 1 ± 1.66. 49.2% were treated with BIC/FTC/TAF.

97.8% vs 89.7% of patients were persistent after the first for DTG/3TC and BIC/FTC/TAF respectively [OR= 5.1 (CI95% 1.7-15.6);p=0.002].

Overall, mean persistence duration was 1.189 days (CI 95% 1.163-1.215). Persistence with DGT/3TC was 1.231 days (CI 95% 1.206-1.255) and persistence with BIC/FTC/TAF was 980 days (CI 95% 944-1.016);p=0.001. However Cox-model adjusted HR was 2.5 (IC95% 0.5-12;p=0.26).

The main reasons for discontinuation for BIC/FTC/TAF were tolerability/toxicity (n=9) and death (n=3). Only two patients withdrawed DTG/3TC, due to toxicity (n=1) and death (n=1).

Conclusion and Relevance In our study, more patients on DTG/3TC were persistent after the first year compared to BIC/FTC/TAF. However, there were no differences in overall persistence in covariate-adjusted analysis. Main reason for BIC/FTC/TAF discontinuation was tolerability/toxicity.

Conflict of Interest No conflict of interest