A randomised controlled trial to compare the efficacy, safety, and tolerability of low dose, short course primaquine in adults with uncomplicated P. vivax malaria in two hospitals in India

Background: Plasmodium vivax remains a major challenge for malaria control and elimination due to its ability to cause relapsing illness. To prevent relapses the Indian National Center for Vector Borne Diseases Control (NCVBDC) recommends treatment with primaquine at a dose of 0.25 mg/kg/day provided over 14 days. Shorter treatment courses may improve adherence and treatment effectiveness. Methods: This is a hospital-based, randomised, controlled, open-label trial in two centres in India. Patients above the age of 16 years, with uncomplicated vivax malaria, G6PD activity of ≥ 30% of the adjusted male median (AMM) and haemoglobin levels ≥ 8 g/dL will be recruited into the study and randomised in a 1:1 ratio to receive standard schizonticidal treatment plus 7-day primaquine at 0.50 mg/kg/day or standard care with schizonticidal treatment plus 14-day primaquine at 0.25 mg/kg/day. Patients will be followed up for 6 months. The primary endpoint is the incidence risk of any P. vivax parasitaemia at 6 months. Safety outcomes include the incidence risk of severe anaemia (haemoglobin 25% fall in haemoglobin and an acute drop in haemoglobin of > 5 g/dL during primaquine treatment. Discussion: This study will evaluate the efficacy and safety of a 7-day primaquine regimen compared to the standard 14-day regimen in India. Results from this trial are likely to directly inform national treatment guidelines. Trial registration: Trial is registered on CTRI portal, Registration No: CTRI/2022/12/048283

Estimating the proportion of relapse following treatment of Visceral Leishmaniasis: meta-analysis using Infectious Diseases Data Observatory (IDDO) systematic reviewResearch in context

Summary: Background: Occurrences of relapse after 6-months post-treatment has been reported in recent Visceral Leishmaniasis (VL) efficacy studies. A meta-analysis was carried out to quantify the proportion of relapses observed at and beyond 6-months using the Infectious Diseases Data Observatory (IDDO) systematic review (SR) database. Methods: Studies in the IDDO SR database (1983–2021; 160 studies) were eligible for inclusion if follow-up was at least 6-months, relapse was clearly reported, and patients with HIV coinfections were excluded. Meta-analysis of single proportion was undertaken and the estimates were reported with 95% confidence intervals (CI). Findings: Overall, 131 studies enrolling 27,687 patients were included; 1193 patients relapsed. In the Indian sub-continent (ISC), relapse estimates at 6-months was 4.5% [95% CI: 2.6%–7.5%; I2 = 66.2%] following single dose liposomal amphotericin B (L-AmB) and 1.5% [95% CI: 0.7%–3.3%; I2 = 0%] for L-AmB in a combination therapy. In East Africa (EA), corresponding estimates were 3.8% [95% CI: 1.3%–10.9%; I2 = 75.8%] following pentavalent antimony (PA), and 13.0% [95% CI: 4.3%–33.6%; I2 = 0%] for PA + paromomycin. From 21 studies with follow-up longer than 6-months, 0.6% [95% CI: 0.2%–1.8%; I2 = 0%] of patients relapsed after 6-months and estimated 27.6% [95% CI: 11.2%–53.4%; I2 = 12%] of relapses would have been missed by a 6-month follow-up. Interpretation: The estimated relapse proportion ranged from 0.5% to 4.5% in ISC and 3.8%–13.0% in EA with the currently recommended drugs. Over one-quarter of relapses would be missed with 6-months follow-up suggesting a longer follow-up may be warranted. Funding: Wellcome Trust (ref: 208378/Z/17/Z)