The SINGLE study was a randomized, double-blind, noninferiority study that evaluated the safety and efficacy of 50 mg dolutegravir + abacavir/lamivudine versus efavirenz/tenofovir/emtricitabine in 833 ART-naive HIV-1 + participants. Of 833 randomized participants, 71% in the dolutegravir + abacavir/lamivudine arm and 63% in the efavirenz/tenofovir/emtricitabine arm maintained viral loads of <50 copies per milliliter through W144 (P = 0.01). Superior efficacy was primarily driven by fewer discontinuations due to adverse events in the dolutegravir + abacavir/lamivudine arm [dolutegravir + abacavir/lamivudine arm, 16 (4%); efavirenz/tenofovir/emtricitabine arm, 58 (14%)] through W144 [corrected]. No treatment-emergent integrase or nucleoside resistance was observed in dolutegravir + abacavir/lamivudine recipients through W144.

Prior attempts to reduce the number of drugs needed to maintain viral suppression in patients with suppressed HIV replication while receiving three antiretroviral drugs have been unsuccessful. In 205 patients with suppressed HIV replication on lopinavir-ritonavir and two nucleosides, this randomized, open-label, non-inferiority clinical trial compared the strategies of continuation of triple therapy versus lopinavir-ritonavir monotherapy followed by reinduction with two nucleosides if virological rebound occurred without genotypic resistance to lopinavir-ritonavir. The primary endpoint was proportion of patients without therapeutic failure, defined as confirmed HIV RNA higher than 500 copies/mL (with exclusion of patients receiving monotherapy who resuppressed to < 50 copies/mL after resuming baseline nucleosides), or loss to follow-up, or change of randomized therapy other than reinduction. At week 48, the percentage of patients without therapeutic failure was 94% in the monotherapy group versus 90% in the triple therapy group (difference,-4%; upper limit of 95% confidence interval for difference, 3.4%). The percentage of patients with HIV RNA 50 copies/mL at 48 weeks by intention-to-treat, missing data or reinductions considered as failures, were 85% in the monotherapy group versus 90% in the triple therapy group (P = 0.31; 95% upper limit of 95% confidence interval for difference, 14%). In this trial, 48 weeks of lopinavir-ritonavir monotherapy with reintroduction of nucleosides as needed was non-inferior to continuation of two nucleosides and lopinavir-ritonavir in patients with prior stable suppression. However, episodes of low level viremia were more common in patients receiving monotherapy.

The OK04 trial has shown that 48 weeks of lopinavir-ritonavir monotherapy with reintroduction of nucleosides as needed was noninferior to continuation of triple therapy with 2 nucleosides and lopinavir-ritonavir in patients with prior stable suppression. However, it is still uncertain if this experimental strategy can maintain suppression in the long term. Patients entered this noninferiority trial (upper limit 95% confidence interval: +12%) with no history of virological failure while receiving a protease inhibitor and receiving 2 nucleosides plus lopinavir/ritonavir, with HIV RNA 500 copies per milliliter with exclusion of monotherapy patients who resuppressed to <50 copies per milliliter after resuming baseline nucleosides, or loss to follow-up, or change of randomized therapy other than reinduction. Through 96 weeks, percentage of patient without therapeutic failure was 87% (monotherapy, n = 100) vs. 78% (triple therapy, n = 98; 95% confidence interval: -20% to +1.2%). Percentage with HIV RNA <50 copies per milliliter (intention to treat, missing = failure, reinduction = failure): 77% (monotherapy) vs. 78% (triple therapy). Low-level viral rebound was more frequent in the monotherapy group. Twelve patients in the monotherapy group (12%) needed reinduction with nucleosides. Discontinuations due to adverse events were significantly more frequent in the triple therapy group (8%) than in the monotherapy group (0%); P = 0.003. At 96-week lopinavir/ritonavir monotherapy with reintroduction of nucleosides as needed was noninferior to continuation of triple therapy. Incidence of adverse events leading to treatment discontinuation was significantly lower with monotherapy. (ClinicalTrials.gov number, NCT00114933).