Reducing the Risk of P. Vivax After Falciparum Infections in Co-endemic Areas (PRIMA)

Reducing the Risk of P. Vivax After Falciparum Infections in Co-endemic Areas - a Randomized Controlled Trial

International Centre for Diarrhoeal Disease Research, Bangladesh, Tribhuvan University, Nepal, Arba Minch University, Addis Ababa University

This study is designed as a multi-centre randomized, open label trial to compare the safety and efficacy of a high dose primaquine (PQ) treatment in G6PD normal patients with P. falciparum to reduce the risk of subsequent P. vivax episodes to current standard practice of providing only schizontocidal treatment.

Plasmodium vivax forms dormant liver stages that reactivate weeks or months following an acute infection. Recurrent infections can be associated with a febrile illness, a cumulative risk of severe anaemia, direct and indirect mortality, and are the most important source of onward transmission of the parasite. In co-endemic areas, there is a very high risk (up to 50%) of patients representing with P. vivax malaria following treatment of P. falciparum. Hence, in co-endemic regions there is a strong rationale for eradicating P. vivax hypnozoites from the liver in patients presenting with uncomplicated P. falciparum infections. The recently completed multicentre IMPROV study compared the efficacy of a 7 day primaquine regimen (1.0 mg/kg/day for 7 days) with a 14 day regimen (0.5 mg/kg/day for 14 days). The 7 day PQ regimen was non-inferior to the 14 day regimen and 5-fold more efficacious at reducing P. vivax recurrence than the control. This study is designed as a multicentre randomized, open label trial to compare the safety and efficacy of a high dose PQ treatment in G6PD normal patients with P. falciparum to reduce the risk of subsequent P. vivax episodes to current standard practice of providing only schizontocidal treatment.

proportion of patients vomiting their medication on the day of enrollment within 1 hour of administration

incidence risk of severe anaemia (Hb<5g/dl) and moderately severe anaemia (<7g/dl) and/or the risk for blood transfusion between day 3 and 7

incidence risk of severe anaemia (Hb<5g/dl) and moderately severe anaemia (<7g/dl) and/or the risk for blood transfusion between day 3 and 7

• The incidence risk of ≥25% fall in haemoglobin since baseline with and without hemoglobinuria at day 3 and day 7

• The incidence risk of ≥25% fall in haemoglobin since baseline with and without hemoglobinuria at day 3 and day 7

The incidence risk of ≥25% fall in haemoglobin to under 7g/dl with and without hemoglobinuria at day 3 and day 7

The incidence risk of ≥25% fall in haemoglobin to under 7g/dl with and without hemoglobinuria at day 3 and day 7

Inclusion Criteria: P. falciparum mono-infection Fever (axillary temperature ≥37.5⁰C) or history of fever in preceding 48 hours Age >1 years (≥ 18 years at the Ethiopia site) G6PD normal as defined by the Biosensor (SD Biosensor, ROK) at ≥70% of the adjusted male median (AMM) for each site Written informed consent Able to comply with all study procedures and timelines Exclusion Criteria: General danger signs or symptoms of severe malaria Anaemia, defined as Hb <8g/dl Pregnant women as determined by Urine β-HCG pregnancy test Breast feeding women Known hypersensitivity to any of the drugs given Regular use of drugs with haemolytic potential Blood transfusion within the last 4 months

Study Protocol and Statistical Analysis Plan will be made available to others. Data collected for the study, including individual patient data and the final trial dataset are reserved for the chief investigator and co-investigators of the trial. The trial will be reported in accordance with the Consolidated Standards of Reporting Trials (CONSORT) guidelines. Trial results will be published in peer-reviewed open access journals and disseminated to trial stakeholders, including participants, as per ethical guidelines.

The data are available for access via the WorldWide Antimalarial Resistance Network (WWARN.org). Requests for access will be reviewed by a Data Access Committee to ensure that use of data protects the interests of the participants and researchers according to the terms of ethics approval and principles of equitable data sharing. Requests can be submitted by email to malariaDAC@iddo.org via the Data Access Form available at WWARN.org/accessing-data. The WWARN is registered with the Registry of Research Data Repositories (re3data.org).

Thriemer K, Degaga TS, Christian M, Alam MS, Ley B, Hossain MS, Kibria MG, Tego TT, Abate DT, Weston S, Karahalios A, Rajasekhar M, Simpson JA, Rumaseb A, Mnjala H, Lee G, Anose RT, Kidane FG, Woyessa A, Baird K, Sutanto I, Hailu A, Price RN. Reducing the risk of Plasmodium vivax after falciparum infections in co-endemic areas-a randomized controlled trial (PRIMA). Trials. 2022 May 18;23(1):416. doi: 10.1186/s13063-022-06364-z.