Background: A single-tablet regimen (STR) has been associated with better drug adherence. However, the durability of different STRs was unknown in the real-world settings. Our aim was to investigate the durability of different initial STR regimens in antiretroviral-naive patients starting STR in southern Taiwan.
Method: This was a retrospective study of antiretroviral-naive patients that initiated first-line antiretroviral regimens with STRs between May 2016 and December 2017. The primary endpoint was time to virological failure. Secondary endpoints were STR discontinuation due to toxicity/intolerance. Durability was defined as time from the initiation until discontinuation/modification. Kaplan- Meier curves were plotted assessing time to virological suppression, treatment failure and discontinuation for the three STRs and Cox proportional hazards model was used to analyze the factors associated with time to viral suppression, treatment failure or discontinuation.
Results: Two hundred and twenty-three patients were included: The median follow-up duration (IQR) was 73.9 (48-101.6) weeks, 25 patients (11%) experienced virological failure; the 48 weeks probability of treatment failure was 22.9% (16/70) for Efavirenz/Emtricitabine/Tenofovir Disoproxil Fumarate (EFV/FTC/TDF), 24.1% (13/54) for Emtricitabine/Rilpivirine/Tenofovir Disoproxil Fumarate (FTC/RPV/TDF) and 24.2% (24/99) for Abacavir/Dolutegravir/Lamivudine (ABC/DTG/3TC) (p=0.16). Fifty-six patients (25%) discontinued their STRs owing to toxicity/intolerance. When compared to EFV/FTC/TDF, treatment with FTC/RPV/TDF (aHR 8.39, CI 1.98-35.58, p = 0.004) and ABC/DTG/3TC (aHR 8.40, CI 2.39-29.54, p=0.001) were more likely to have treatment failure. The predictors for treatment failure included age ≦ 30 years old (aHR 3.73, CI 1.25-11.17, p = 0.018), switch between different STR (aHR 2.3, CI 1.18-4.50, p = 0.001) and free of active syphilis infection (aHR 0.24, CI 0.08-0.73, p = 0.012). The risk factor for treatment discontinuation included younger age ≦ 30 years old (aHR 3.82, CI 1.21-12.37, p = 0.023), treatment with EFV/FTC/TDF (aHR 8.65, CI 2.64-28.39, p < 0.001) and free of active syphilis infection (aHR 0.16, CI 0.04-0.62, p = 0.006).
Conclusion: Younger age was associated with treatment failure and drug discontinuation. Active syphilis infection s/p treatment was associated with free from treatment failure and discontinuation. This probably driven by the more frequently sexual health education and counseling when patients had syphilis infection. Treatment with ABC/DTG/3TC was associated with higher risk of treatment failure. The STR durability was dependent on the drug toxicity/intolerance, age and syphilis infection.
Keywords: Antiretroviral therapy; Drug resistance; Durability; HIV; Single tablet regimen.
© 2021. The Author(s).