Clinical use and effectiveness of dolutegravir and lamivudine: a long-term, real-world, retrospective study

Background: The use of dolutegravir/lamivudine is based on solid clinical trials; however, real-world data remain limited.

Objectives: To provide data on the clinical use and effectiveness of dolutegravir/lamivudine in persons with HIV in a real-world scenario.

Patients and methods: Retrospective, single-centre and observational study. We included all adults starting dolutegravir/lamivudine since November 2014. We reported all demographic, virological and immunological variables at baseline and assessed effectiveness [on treatment (OT), modified ITT (mITT) and ITT in those persons who reached 6 and 12 month follow-ups (M6 and M12).

Results: Of the 1058 persons, 9 were treatment-naive; the final analysis included 1049 treatment-experienced people with HIV. Median (IQR) follow-up was 1 (0.3-1.6) years, with 81% and 63% persons reaching M6 and M12, respectively. The longest use of dolutegravir/lamivudine was 7.4 years. Per OT, mITT and ITT, HIV-RNA < 50 copies/mL was 97%, 92% and 81% (M6) and 98%, 90% and 80% (M12), respectively. Females [adjusted risk ratio, aRR (95% CI): 1.69 (1.19-2.40)]; immediate, previous PI-based regimen [aRR (95% CI): 1.67 (1.09-2.56)]; and viral load (VL) ≥ 50 copies/mL at dolutegravir/lamivudine initiation [aRR (95% CI): 3.36 (2.32-4.88)] were independently associated with lack of effectiveness at M12; other demographic, immunological and virological variables like previous M184V/I substitutions or virological failure, were unrelated. Of the total, 944 (90%) continued dolutegravir/lamivudine. The most frequent known reason for discontinuation was toxicity [48 (46%) cases].

Conclusions: In our real-world experience, virological suppression rates were high for treatment-experienced persons on dolutegravir/lamivudine; however, we identified subgroups with a higher risk of lack of effectiveness at M12, who may benefit from closer follow-ups.