Switch to DTG/3TC matches TAF-based regimen in HIV viral suppression over 96 weeks

Switching to a dual therapy of dolutegravir/lamivudine (DTG/3TC) was noninferior to continuing on a TAF*-based regimen in maintaining virologic suppression over 96 weeks in virally suppressed adults with HIV-1, according to the long-term data from TANGO presented at the 2020 HIV Glasgow Congress.

In the phase III, open-label, noninferiority trial, 741 virologically suppressed adults with HIV were randomized 1:1 to either continue on a TAF-based regimen containing at least three drugs or switch to a two-drug regimen of DTG/3TC for 148 weeks. The participants had to be virologically suppressed for more than 6 months, with no prior virologic failure and no major resistance to NRTI or INSTI** to be eligible for inclusion. [HIV Glasgow 2020, abstract O411]

Previously, TANGO has shown positive results at week 48 in the IAS 2019 Congress, suggesting that DTG/3TC was similarly effective as a TAF-based regimen for maintenance of viral suppression.

The current analysis presented data up to 96 weeks, showing that switching to DTG/3TC was able to maintain similar rates of virologic suppression as continuing on a TAF-based regimen — thus raising the question of whether three-drug regimens are still necessary for maintenance in this group of people.

At 96 weeks, virologic success rates (HIV-1 RNA <50 copies/mL), assessed based on the FDA Snapshot algorithm, were high and similar in both the DTG/3TC and TAF-based regimen arms (85.9 percent vs 79.0 percent) for the intention-to-treat population — meeting the noninferiority margin between the two treatments.

For Snapshot virologic failure (defined as HIV-1 RNA ≥50 copies/mL), switching to DTG/3TC was also noninferior to continuing on a TAF-based regimen in the intention-to-treat analysis (0.3 percent vs 1.1 percent; adjusted difference, −0.8 percent, 95 percent confidence interval [CI], −2.0 to 0.4). DTG/3TC turned out to be superior to the TAF-based regimen for Snapshot virologic failure in the per-protocol analysis (0 percent vs 1.1 percent, adjusted difference, −1.1 percent; p=0.044).

None of the participants in the DTG/3TC arm had protocol-defined virologic failure with no resistance detected at failure, compared with three on TAF-based regimen.

Due to interruptions from the COVID-19 pandemic, there were missing data for 44 participants (5.9 percent) in the week 96 window.

Overall, adverse event (AE) occurred at similar rates between both arms (87.8 percent vs 87.6 percent), with more drug-related grade 2–5 AEs in the DTG/3TC arm than the TAF-based regimen (5.7 percent vs 1.9 percent).

“The safety profile of DTG/3TC was consistent with the DTG and 3TC respective labels,” reported presenting author Dr Stéphane De Wit from St Pierre University Hospital in Brussels, Belgium.

In terms of lipid profile, LDL-cholesterol, total cholesterol (TC), and triglycerides significantly improved in participants who switched to DTG/3TC, whereas changes in HDL-cholesterol favoured the TAF-based regimen. There was no difference in TC/HDL-C ratio between both treatment arms.

“DTG/3TC two-drug regimen offers a robust switch option with durable efficacy, good safety and tolerability, and a high barrier to resistance with zero protocol-defined virologic failure through 96 weeks,” De Wit pointed out.

*TAF: Tenofovir alafenamide fumarate
**NRTIs: Nucleoside Reverse Transcriptase Inhibitors; INSTI: Integrase strand transfer inhibitor