0.8% of adults with HIV-1 had HIV-1 RNA ≥50 copies/mL at Week 48 on bictegravir/lenacapavir

At Week 48, 0.8% of adults with HIV-1 who switched to bictegravir/lenacapavir had HIV-1 RNA ≥50 copies/mL, compared with 1.1% who continued a stable baseline regimen, the trial's registry record shows. The Phase 3 comparison reports results for 371 participants in the combination group and 186 in the stable-regimen group, according to the record.

Why it matters

The trial focused on adults whose HIV-1 was suppressed but who were taking complex antiretroviral regimens because of prior viral resistance, intolerance, or a contraindication to existing single-tablet regimens. The criteria required that participants had been on their regimen for at least 6 months and had no documented or suspected resistance to bictegravir. The FDA-approved Biktarvy label identifies bictegravir as part of a complete HIV-1 treatment regimen for adults and pediatric patients weighing at least 14 kg; the trial record lists Biktarvy with other drugs as an example of a complex regimen.

Week 48 results

Results first posted: 2026-10-21.

The primary outcome was the percentage of participants with HIV-1 RNA ≥50 copies/mL at Week 48 under the US FDA-defined Snapshot Algorithm. The record reports 0.8% for participants assigned to bictegravir/lenacapavir 75 mg/50 mg as a fixed-dose combination and 1.1% for those assigned to continue their stable baseline regimen. The estimated difference between groups was -0.3 percentage points, with a two-sided 95.002% confidence interval from -2.3 to 1.8.

For the secondary measure of HIV-1 RNA below 50 copies/mL at Week 48, the record reports 96.0% in the bictegravir/lenacapavir group and 93.5% in the stable baseline regimen group. The estimated difference was 2.4 percentage points, with a two-sided 95.002% confidence interval from 1.8 to 6.6. The record's description says this measure included participants whose last available on-treatment result was below 50 copies/mL in the Week 48 analysis window, which ran from Days 295 to 378.

Trial design and participants

ARTISTRY-1 is a combined Phase 2/3 randomized, open-label, multicenter, active-controlled study, run as one continuous trial. The record lists actual enrollment of 689 participants across the study. In Phase 3, 373 participants were randomized to switch from their stable baseline regimen to the bictegravir/lenacapavir fixed-dose combination, and 188 were randomized to continue their stable baseline regimen, with both groups treated for up to 48 weeks. Two people in each group never started treatment, so the results cover 371 and 186 participants.

Participants in the combination group took bictegravir 75 mg and lenacapavir 50 mg once daily. The record says they also received a 2-day loading dose of lenacapavir 600 mg on Days 1 and 2. Participants in the comparator group continued their stable baseline regimen for up to 48 weeks. Participants could choose to enter an extension period after completing randomized treatment or discontinuing early.

The record describes the Phase 3 population as adults with HIV-1 who were receiving a complex antiretroviral regimen. To enroll, participants needed HIV-1 RNA below 50 copies/mL at screening. A complex regimen could include multiple pills a day, dosing more than once daily, or both parenteral and oral agents, and could reflect resistance, intolerance, or contraindications to simpler regimens. Participants with prior lenacapavir exposure, active tuberculosis, or chronic hepatitis B were excluded.

Safety and what comes next

Treatment-emergent adverse events were reported for 79.5% of participants in the bictegravir/lenacapavir safety group and 81.2% of participants who continued their stable baseline regimen. The record says these events were not necessarily related to treatment. Its definition included adverse events that led to premature study-drug discontinuation, or events with onset on or after the study-drug start date through the last exposure date after permanent discontinuation.

The results record lists additional Phase 3 outcomes for the bictegravir/lenacapavir group at Weeks 96 and 144, but those measures are marked as not posted. The study record estimates completion in 2029-12.