Dolutegravir Monotherapy Versus Dolutegravir/Abacavir/Lamivudine for Virologically Suppressed People Living With Chronic Human Immunodeficiency Virus Infection: The Randomized Noninferiority MONotherapy of TiviCAY Trial

Clin Infect Dis. 2019 Oct 15;69(9):1498-1505. doi: 10.1093/cid/ciy1132.


Background: We investigated whether dolutegravir (DTG) monotherapy could be used to maintain virological suppression in people living with human immunodeficiency virus (HIV) on a successful dolutegravir-based triple therapy.

Methods: MONCAY (MONotherapy of TiviCAY) was a 48-week, multicentric, randomized, open-label, 12% noninferiority margin trial. Patients with CD4 nadir >100/μL, plasma HIV-1 RNA <50 copies/mL for ≥12 months, and stable regimen with DTG/abacavir (ABC)/lamivudine (3TC) were 1:1 randomized to continue their regimen or to DTG monotherapy. The primary endpoint was the proportion of patients with HIV RNA <50 copies/mL at week 24 in intention-to-treat snapshot analysis. Virologic failure (VF) was defined as 2 consecutive HIV RNA >50 copies/mL within 2 weeks apart.

Results: Seventy-eight patients were assigned to DTG monotherapy and 80 to continue DTG/ABC/3TC. By week 24, 2 patients in the DTG group experienced VF without resistance to the integrase strand transfer inhibitor (INSTI) class; 1 patient discontinued DTG/ABC/3TC due to an adverse event. The success rate at week 24 was 73/78 (93.6%) in the DTG arm and 77/80 (96.3%) in the DTG/ABC/3TC arm (difference, 2.7%; 95% confidence interval [CI], -5.0 to 10.8). During subsequent follow-up, 5 additional VFs occurred in the DTG arm (2 of which harbored emerging resistance mutation to INSTI). The cumulative incidence of VF at week 48 was 9.7% (95% CI, 2.8 to 16.6) in the DTG arm compared with 0% in the DTG/ABC/3TC arm (P = .005 by the log-rank test). The Data Safety Monitoring Board recommended to reintensify the DTG arm with standardized triple therapy.

Conclusions: Because the risk of VF with resistance increases over time, we recommend avoiding DTG monotherapy as a maintenance strategy among people living with chronic HIV infection.

Clinical trials registration: NCT02596334 and EudraCT 2015-002853-36.

Keywords: INSTI resistance; dolutegravir; maintenance; monotherapy; virologic failure.

Publication types

  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Anti-HIV Agents / therapeutic use*
  • Confidence Intervals
  • Dideoxynucleosides / therapeutic use*
  • Drug Resistance, Viral / genetics
  • Female
  • HIV Infections / drug therapy*
  • Heterocyclic Compounds, 3-Ring / therapeutic use*
  • Humans
  • Lamivudine / therapeutic use*
  • Male
  • Middle Aged
  • Mutation / genetics


  • Anti-HIV Agents
  • Dideoxynucleosides
  • Heterocyclic Compounds, 3-Ring
  • Lamivudine
  • dolutegravir
  • abacavir

Associated data

  • EudraCT/2015-002853-36