Larry Buhl | 08 Nov, 2022
Two-Drug Regimens in the Real World: Efficacy of DTG/3TC
Gerald Pierone, Jr., M.D., the medical director of the Whole Family Health Center in Vero Beach, Florida, shared data on real world effectiveness of fixed-dose dolutegravir/lamivudine (DTG/3TC) as a two-drug regimen compared with common three-drug regimens among virally suppressed, treatment-experienced PLWH.
A coformulation of dolutegravir (DTG, Tivicay), a first-generation integrase inhibitor, and lamivudine (3TC, Epivir), a venerable NRTI, was approved by the FDA in April 2019 under the brand name Dovato. DTG/3TC is listed within U.S. HIV treatment guidelines as a recommended first-line treatment regimen in individuals who do not have a very high viral load, are not coinfected with hepatitis B, and for whom reverse transcriptase genotypic resistance testing results are available.
The study by Pierone and colleagues extended from May 1, 2019 (i.e., after DTG/3TC’s approval) through Oct. 31, 2020, with follow-up until April 2021. Patient records, drawn from the OPERA longitudinal database, included virally suppressed PLWH (in this study, that was defined as less than 200 copies/mL) who had switched from their prior regimen to one of three alternatives: DTG/3TC; a three-drug regimen containing dolutegravir (“DTG 3DR” for short); or a three-drug regimen containing bictegravir (“BIC 3DR” for short), a second-generation integrase inhibitor contained within the FDA-approved combo pill bictegravir/emtricitabine/tenofovir alafenamide (a.k.a. Biktarvy).
The researchers analyzed records of 8,037 PLWH fitting these criteria. The population was relatively diverse: 19% women, 35% Black, and 26% Latinx, with 54% of patients living in the U.S. South. The vast majority of patients were prescribed BIC 3DR, but notably, the proportion of Black patients and southern patients was highest in the subgroup that was prescribed DTG 3DR.
They found that, after a median of 13 to 16 months of follow-up (varying by study arm), virologic failure rates were low across all regimens—but only DTG 3DR was associated with a statistically significant increase in the risk of virologic failure relative to DTG/3TC (hazard ratio 5.21; 95% CI 1.85 to 14.67). BIC 3DR trended toward an increased risk, but fell short of statistical significance (HR 1.39; CI 0.61 to 3.17).
Discontinuation rates were higher for the DTG 3DR cohort (24.9 per 100 person-years) than the DTG/3TC group (17.7 per 100 person-years) or the BIC 3DR group (8.3 per 100-person years), amounting to a 69% greater discontinuation risk compared to BIC 3DR. Discontinuers on any combination were highly likely to be virally suppressed at the time of discontinuation (96% on DTG/3TC; 94% on BIC 3DR; 93% on DTG 3DR), and those discontinuations were unlikely to be due to adverse events or side effects: only 3% experienced adverse events with DTG/3TC, 4% with DTG 3DR, and 7% with BIC 3DR. The most common reason for DTG 3DR discontinuations was regimen simplification (21%); no reason was given for more than half of the discontinuations in each cohort.
Pierone concluded by saying that, because discontinuations were not attributed to the treatment, and because virologic failure was rare after switching to DTG/3TC, DTG 3DR, and BIC 3DR, all combinations showed high levels of suppression and tolerability.
Read the full article at https://www.thebodypro.com/article/idweek-2022-new-hiv-antiretroviral-therapy