Virologic efficacy of tenofovir, lamivudine and dolutegravir as second-line antiretroviral therapy in adults failing a tenofovir-based first-line regimen.
Keene CM., Griesel R., Zhao Y., Gcwabe Z., Sayed K., Hill A., Cassidy T., Ngwenya O., Jackson A., van Zyl G., Schutz C., Goliath R., Flowers T., Goemaere E., Wiesner L., Simmons B., Maartens G., Meintjes G.
ObjectiveRecycling tenofovir and lamivudine/emtricitabine (XTC) with dolutegravir would provide a more tolerable, affordable, and scalable second-line regimen than dolutegravir with an optimized nucleoside reverse transcriptase inhibitor (NRTI) backbone. We evaluated efficacy of tenofovir/lamivudine/dolutegravir (TLD) in patients failing first-line tenofovir/XTC/efavirenz or nevirapine.DesignSingle arm, prospective, interventional study.SettingTwo primary care clinics in Khayelitsha, South Africa.ParticipantsSixty adult patients with two viral loads greater than 1000 copies/ml.InterventionParticipants were switched to TLD with additional dolutegravir (50 mg) for 2 weeks to overcome efavirenz induction.Primary outcomeProportion achieving viral load less than 50 copies/ml at week 24 using the FDA snapshot algorithm.ResultsBaseline median CD4+ cell count was 248 cells/μl, viral load 10 580 copies/ml and 48 of 54 (89%) had resistance (Stanford score ≥15) to one or both of tenofovir and XTC. No participants were lost to follow-up. At week 24, 51 of 60 [85%, 95% confidence interval (CI) 73-93%] were virologically suppressed, six had viral load 50-100 copies/ml, one had viral load 100-1000 copies/ml, one no viral load in window, and one switched because of tenofovir-related adverse event. No integrase mutations were detected in the one participant meeting criteria for resistance testing. Virological suppression was achieved by 29 of 35 (83%, 95% CI 66-93%) with resistance to tenofovir and XTC, 11 of 13 (85%, 95% CI 55-98%) with resistance to XTC, and six of six (100%, 95% CI 54-100%) with resistance to neither.ConclusionA high proportion of adults switching to second-line TLD achieved virologic suppression despite substantial baseline NRTI resistance and most not suppressed had low-level viraemia (≤100 copies/ml). This suggests recycling tenofovir and XTC with dolutegravir could provide an effective second-line option.