Effectiveness and tolerability of dolutegravir and abacavir/lamivudine administered as two separate pills compared to their equivalent single-tablet regimen in a multicentre cohort in Spain.

Introduction: We aimed to assess the effectiveness and tolerability of dolutegravir (DTG), abacavir (ABC) and lamivudine (3TC) administered as branded STR (DTG/ABC/3TC) or as two separate pills (DTG and either branded ABC/3TC [DTG+(ABC/3TC)b] or generic ABC/3TC [DTG+(ABC/3TC)g]).

Methods: We included individuals from the multicentre cohort of the Spanish HIV/AIDS Research Network (CoRIS) who received DTG/ABC/3TC, DTG+(ABC/3TC)b or DTG+(ABC/3TC)g during 2015 to 2018. We used multivariable logistic regression to compare the proportion of antiretroviral-naïve individuals who achieved viral suppression (VS) (viral load ≤50 copies/mL) at 24 weeks of initiating with DTG+(ABC/3TC)b or DTG+(ABC/3TC)g versus DTG/ABC/3TC. We also calculated the proportion of virologically suppressed individuals who maintained VS at 24 weeks after switching from DTG/ABC/3TC to DTG+(ABC/3TC)g.

Results: During the study period, 829, 68 and 47 treatment-naïve individuals started treatment with DTG/ABC/3TC, DTG+(ABC/3TC)b or DTG+(ABC/3TC)g respectively. The proportions of individuals who changed their regimens due to side effects during the first 24 weeks were 3.7%, 4.4% and 6.4% respectively (p = 0.646). We did not find significant differences in VS at 24 weeks among individuals starting with DTG+(ABC/3TC)b or DTG+(ABC/3TC)g compared to those initiating with DTG/ABC/3TC. Among 177 virologically suppressed individuals who switched from DTG/ABC/3TC to DTG+(ABC/3TC)g, 170 (96.0%) maintained VS at 24 weeks.

Conclusions: In naïve individuals, the effectiveness and tolerability at 24 weeks of DTG plus ABC/3TC administered as two separate pills, either as branded or generic ABC/3TC, was similar to the STR DTG/ABC/3TC. Switching the STR DTG/ABC/3TC to its separate components DTG+(ABC/3TC)g in virologically suppressed individuals did not seem to impair its effectiveness.