Design: Phase 3b, open-label, randomised non-inferiority trial
Population: 537 adults in Kenya, South Africa and Uganda with suppressed HIV-1 and adherence difficulties
Primary outcome: Viral load below 50 copies/mL at week 48
Effect: 91.0% vs 89.2% (difference 1.9 points, −3.1 to 6.9); confirmed failure 1.9% vs 0%

IMPALA, an open-label phase 3b trial in Kenya, South Africa and Uganda published in NEJM on 15 October, enrolled 540 adults with suppressed HIV but a record of poor adherence or care engagement. They were randomised to injectable cabotegravir plus rilpivirine every eight weeks or to continue oral dolutegravir-based therapy. Baseline resistance testing was not done.

At 48 weeks, 91.0% on injections and 89.2% on oral therapy had a viral load below 50 copies/mL, which met non-inferiority. Five people on injections had confirmed virological failure, against none on oral therapy.

The result supports injectables as an option for people who find daily pills hard. The failures are the caution: rilpivirine resistance is more common in some settings, and failure on this combination can leave resistance to two drug classes.

Availability and cost in India are not established by this trial.

Consider long-acting injectable therapy for people with suppressed HIV who struggle with daily pills.
Check for rilpivirine resistance risk before switching where resistance testing is available.
Monitor viral load closely after a switch; failures on injectables can carry two-class resistance.
Missed injection windows matter more than missed pills; build reminders into care.

Why it matters

It tests injectables in the people most likely to need them, in a setting where pills are the default.

The statistics, in plain English

The difference in suppression was 1.9 points (95% CI −3.1 to 6.9). The lower limit is well above the −10-point margin set in advance, so injections were not meaningfully worse. Virological failure was 1.9% against 0% (0.3 to 3.5), a small but real excess.