Abstract Body

The SWORD studies demonstrated non-inferiority on switch to dolutegravir (DTG) + rilpivirine (RPV) vs continuing a 3- to 4-drug Current Antiretroviral Regimen (CAR) for 48 weeks, and also showed long term suppression to HIV-1 RNA <50 c/mL. The clinical significance of low-level viral load (VL) <50c/mL remains unclear. We present here low level qualitative VL data from the Phase 3 SWORD studies up to Week 148.

Adults with VL<50 c/mL for ≥6 months were randomized to switch to DTG+RPV (Early Switch (ES) group) for 148 weeks or continue CAR. CAR participants <50c/mL at Week 48 switched at Week 52 (Late Switch (LS) group) to receive DTG+RPV for 96 weeks. The Abbott Realtime assay measures VL quantitatively from 40c/mL to 10,000,000c/mL; when VL<40c/mL it returns qualitative Target Detected (TD) or Target Not Detected (TND) results. We explored participants’ TND and TD status over time, overall and by Baseline TD or TND status.  

1024 participants were randomized and exposed (ES DTG+RPV 513; CAR 511) across both studies; 477 CAR participants switched to DTG+RPV at Week 52. The proportions of participants with TND at all visit weeks were similar and did not decline over time (Figure); TND ranges across visits were 75%-88% in the ES group, 79%-90% in the LS group and 79%-88% in the CAR group. Participant proportions with BL TND and TND at all visits through 48 Weeks exposure in comparator ES DTG+RPV, LS DTG+RPV, and CAR groups were respectively 47% (180/383), 52% (189/367), and 53% (215/408), and for participants with BL TD the proportions with TND at all visits were respectively 19% (18/94), 33% (25/76), and 19% (13/70). Among participants in the ES DTG+RPV group with pre-switch TND vs TD, the proportions with TND at all visits through Week 148 were respectively 23% (79/341) vs 10% (8/84), and among LS DTG+RPV group the proportions with TND through Week 148 (96 weeks of DTG+RPV) were 40% (142/352) vs 20% (15/76). In the ES DTG+RPV group, 20% of the 433 participants who reached Week 148 had TND at all visits, and in the LS DTG+RPV group, 36% of the 434 participants who reached Week 148 (with 96 weeks of DTG+RPV exposure) had TND at all visits.

The frequency of participants with TND status under DTG+RPV remained high across all visits with no decline observed through 148 weeks. This is supportive evidence that long term treatment with DTG+RPV is efficacious in virologic suppression to <50c/mL.