Once-weekly oral islatravir–lenacapavir held HIV suppression as well as a daily single tablet

Design

Phase 3, randomised, double-blind, active-controlled, non-inferiority

Population

607 adults with HIV-1 suppressed ≥6 months on B/F/TAF, 12 countries

Primary outcome

HIV-1 RNA ≥50 copies/mL at week 48

Effect

0% vs 0.3%; difference −0.3 points (95% CI −1.4 to 0.8)

This double-blind phase 3 non-inferiority trial, ISLEND-1, published in July, randomised 607 adults in 12 countries whose HIV-1 had been suppressed for at least six months on daily bictegravir–emtricitabine–tenofovir alafenamide. They either switched to once-weekly oral islatravir–lenacapavir or stayed on the daily tablet, each with matched placebo, for 96 weeks.

At 48 weeks, no participant on the weekly regimen had a viral load of 50 copies/mL or higher, against one (0.3%) on the daily tablet: a difference of −0.3 points (95% CI −1.4 to 0.8), well within the 4-point margin. Suppression below 50 copies/mL was 93.4% against 92.4%. CD4 counts changed little in either group. Discontinuation for adverse events was 2.0% against 1.7%.

This is a switch study in people already suppressed and adherent; it does not show the regimen works for treatment-naive patients or for those struggling with daily pills. Islatravir's earlier development was paused over lymphocyte falls at higher doses, so longer follow-up at this dose matters. It is not approved by the FDA or CDSCO, and the trial was industry funded.

• Weekly oral islatravir–lenacapavir is investigational and not available in India.
• The trial enrolled only people already suppressed on daily therapy; it does not address starting treatment.
• Pill fatigue is worth asking about at routine HIV reviews; regimen simplification is becoming a real option.
• Watch for 96-week data and lymphocyte safety before treating weekly oral dosing as established.

Why it matters

It is the first phase 3 evidence that an oral regimen taken once a week can maintain suppression as well as a daily tablet.

Don't overread it

A 48-week switch study in suppressed adults does not establish long-term safety or use in newly diagnosed patients.

The statistics, in plain English

Non-inferiority means the weekly regimen was shown to be no more than 4 percentage points worse than the daily tablet; the confidence interval for the difference (−1.4 to 0.8) sits entirely inside that margin. It does not mean the weekly regimen is better.

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