Efficacy of three regimens of Chloroquine and Primaquine for treatment of P. vivax malaria, Cruzeiro do Sul, Acre, Brazil

An in vivo drug efficacy study conducted in Cruzeiro do Sul, Acre State, Brazil. A total of 257 study participants ≥5 years of age with parasitologically confirmed P. vivax monoinfections were included. Patients were divided in three different treatment groups:

1. Regular dose of primaquine (0.5 mg/kg per day for 7 days) with directly observed therapy;
2. Regular dose of primaquine without directly observed therapy; and
3. Increased total dose of primaquine (0.5 mg/kg per day for 14 days) with directly observed therapy.

All patients received chloroquine (CQ) for three days at a daily dose of approximately 25 mg/Kg in accordance with the Brazilian National Malaria Control guidelines. Primaquine was given for 7 or 14 days under supervision or not, depending on the study group. Clinical and parasitologic parameters were monitored over a 28-day follow-up period to evaluate drug efficacy and for a total period of 168 days (24 weeks) to evaluate chances of recrudescence, relapse, or reinfection.

Blood samples were taken to measure the CQ levels in blood on Day 7 and day of failure, if occurring in the initial 28 days of follow up. In addition, a blood sample was collected on filter paper on first day and on day of suspected failure to help differentiate parasite genotypes using techniques based on polymerase chain reaction.

Results from this drug efficacy study will be used to assist the Brazilian Ministry of Health in assessing their national malaria treatment policy for P. vivax malaria.

• Allocation: Randomized
• Intervention Model: Parallel Assignment
• Intervention Model Description: We plan to compare 3 different regimens of primaquine for P. vivax treatment.
• Masking: None (Open Label)
• Primary Purpose: Treatment
• ClinicalTrials.gov Identifier: NCT03610399

Clinical trial registration

Drug-based Strategies
P. vivax

Apr 2018 — Mar 2019

Brazil