Dihydroartemisinin-piperaquine prevented early vivax recurrence that chloroquine alone did not

Design

Open-label, single-centre, four-arm randomised trial

Population

419 patients with P. vivax malaria in Manaus, Brazil, G6PD activity >30%

Primary outcome

Recurrence rate at day 42

Effect

Delayed primaquine: 2.4% (DHA-PPQ) vs 27.3% (chloroquine), HR 0.08 (95% CI 0.00–0.22)

Curavivax, published in May 2026, was an open-label, single-centre trial in Manaus, Brazil. It randomised 419 patients over six months old with P. vivax malaria and G6PD activity above 30% to dihydroartemisinin-piperaquine or chloroquine, each with primaquine (dosed by bodyweight, once daily for 14 days) started on day 0 or delayed to day 42.

With primaquine from day 0, day-42 recurrence was low in both groups (1.0% vs 2.0%). Without early primaquine, recurrence was 2.4% with dihydroartemisinin-piperaquine and 27.3% with chloroquine (HR 0.08, 95% CI 0.00 to 0.22). All regimens were well tolerated.

The long half-life of piperaquine protects against early relapse when primaquine is delayed or not taken. India also has chloroquine-resistant vivax pockets and poor primaquine adherence, so the finding is relevant here, though national guidance for vivax in India still recommends chloroquine plus primaquine.

• Follow national guidance, which in India recommends chloroquine plus 14-day primaquine for P. vivax.
• If primaquine will be delayed or adherence is doubtful, chloroquine alone gives little protection against early recurrence.
• Check G6PD status before primaquine; the trial excluded patients with activity at or below 30%.
• Report suspected chloroquine failure (recurrence within 28 days) to the programme.

Why it matters

It challenges the reliance on chloroquine in settings where primaquine adherence is poor.

Don't overread it

This is a single-centre Brazilian trial; it does not change Indian national treatment guidance by itself.

The statistics, in plain English

A hazard ratio of 0.08 means over 90% fewer recurrences by day 42 when primaquine was delayed. The comparison with early primaquine had very few events, so its confidence interval is meaninglessly wide. This was one centre in one country.

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