Serological Testing and Treatment for Plasmodium Vivax Malaria: a Trial in Ethiopia and Madagascar (PvSTATEM)

Serological Testing and Treatment for Plasmodium Vivax Malaria: a Cluster-Randomised Trial in Ethiopia and Madagascar

The resilience of P. vivax to malaria elimination efforts is due to its ability to form dormant liver stages (hypnozoites) that reactivate weeks to months after the initial infection causing recurrent episodes of malaria (relapses) and ongoing parasite transmission. Relapses account for a majority of recurrent infections and clinical cases of P. vivax malaria, and therefore have a significant effect on morbidity at the individual level.

With current technology, it is not possible to directly measure hypnozoite biomarkers. Rather than directly detecting hypnozoites, our team developed an indirect approach by measuring antibodies induced by the primary blood-stage infection. Antibodies to different blood-stage antigens decay at different rates. Measuring antibodies to a carefully selected panel of P. vivax antigens can aid to identify individuals who have been infected within the previous 9 months (approximately the lifespan of hypnozoites).

A serological test based on selected P. vivax antigens can detect recent exposure and predict future relapses. Coupling this test with a safe and efficacious primaquine treatment regimen, results in a population-based intervention to target the hypnozoite reservoir. This intervention is referred to as Plasmodium vivax Serological Testing and Treatment (PvSeroTAT).

PvSTATEM is a cluster randomised trial in Madagascar and Ethiopia. This study will provide insights into the feasibility, acceptability, and efficacy of the PvSeroTAT approach. In this study, individuals, randomised by clusters, will be tested for the presence of serological markers of a recent P. vivax infection, followed by a targeted drug treatment intervention aimed at killing P. vivax hypnozoites.

Study Overview

• Status: Recruiting
• Conditions: Plasmodium Falciparum; Plasmodium Vivax; Malaria Falciparum; Malaria Vivax
• Intervention / Treatment: Diagnostic test: Control; Combination product: PvSeroTAT

Detailed Description

In each country, 24 clusters (48 clusters in total) will be randomly allocated using computer generated numbers to one of the two interventions:

Arm 1 (PvSeroTAT intervention) or Arm 2 (Control arm). Within each cluster, approximately 400 participants (range 100-600) will be enrolled, based on the trial's inclusion and exclusion criteria. At baseline (month 0) and month 6 serology for P. vivax infections will be performed in all study participants. In the clusters in the PvSeroTAT arm, participants with a positive P. vivax serology at baseline or month 6 will be approached for treatment. First G6PD enzyme activity will be measured. If the enzyme activity is normal and no other contra-indication for treatment are found, the participants will be treated with 14 days of primaquine 0.25mg/kg/day (Ethiopia) or 7 days of primaquine 0.5mg/kg/day (Madagascar), and a three-day course of either chloroquine (Ethiopia) or artesunate-amodiaquine (Madagascar). It is possible that a participant could receive a radical P. vivax treatment at both baseline (month 0) and month 6. Participants will be monitored for side effects and adherence during the first 7 days after the start of antimalarial treatments. In addition, blood samples will be taken to measure hemoglobin levels to monitor for post-treatment hemolysis.

In the clusters in both arms, the incidence of malaria will be monitored through passive case detection in health posts up to 18 months after the first intervention. All cases that are detected during the passive case detection will be treated according to the national guidelines.

At month 12 and month 18 of the study, a cross sectional survey will be conducted in all study clusters. Blood samples will be taken to determine the prevalence of P. vivax and P. falciparum through PCR assays.

• Study Type: Interventional
• Enrollment (Estimated): 19200
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: Rob W van der Pluijm; Phone Number: 0033145688000; Email: rvanderp@pasteur.fr

Study Locations

• Ethiopia
  • Addis Ababa, Ethiopia
    • Not yet recruiting
    • Armauer Hansen Research Institute
    • Contact: Fitsum T Girma, PhD; Phone Number: +251113483752; Email: fitsum.girma@ahri.gov.et
• Madagascar
  • Antananarivo, Madagascar
    • Recruiting
    • Institut Pasteur de Madagascar
    • Contact: Rindra Randremanana, PhD; Phone Number: +261209741272; Email: rrandrem@pasteur.mg

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Participant will remain in the study area for at least the next month.
• Participant is older than 12 months

Exclusion Criteria:

• Participant is unwilling to participate.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Other: Control arm	Diagnostic test: Control; Two rounds (month 0 and month 6) of serological screening for antibodies against P. vivax in the blood of a subset of eligible cluster inhabitants. Serological status will be assessed at a later stage (months later) and will not lead to treatment of sero-positive individuals.
Experimental: PvSeroTAT intervention	Combination product: PvSeroTAT; Two rounds (month 0 and month 6) of serological screening for antibodies against P. vivax in the blood of all eligible cluster inhabitants. In the clusters in the PvSeroTAT arm, participants with a positive P. vivax serology at baseline or month 6 will be treated with 14 days of primaquine 0.25mg/kg/day (Ethiopia) or 7 days of primaquine 0.5mg/kg/day (Madagascar), and a three-day course of either chloroquine (Ethiopia) or artesunate-amodiaquine (Madagascar)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of individuals with PCR detectable P. vivax blood-stage infections 6 months after the second round of PvSeroTAT or 6 months after the second round of blood sampling in the control clusters.	6 months after the second round of PvSeroTAT, a blood sample will be collected from participants through fingerprick in the intervention clusters. In the control clusters a blood sample to determine PCR prevalence will be collected 6 months after the second round of blood sampling in that control cluster.	6 months after the second round of PvSeroTAT or 6 months after the second round of blood sampling in the control clusters.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Proportion of individuals with PCR detectable P. vivax blood-stage infections 12 months after the second round of PvSeroTAT or 12 months after the second round of blood sampling in the control clusters.	12 months after the second round of PvSeroTAT, a blood sample will be collected from participants through fingerprick in the intervention clusters. In the control clusters a blood sample to determine PCR prevalence will be collected 12 months after the second round of blood sampling in that control cluster.	12 months after the second round of PvSeroTAT or 12 months after the second round of blood sampling in the control clusters.
Proportion of individuals with PCR detectable P. vivax blood-stage infections 6 months after the first round of PvSeroTAT (before second round) or 6 months after the first round of blood sampling in the control clusters.	6 months after the first round of PvSeroTAT, a blood sample will be collected from participants through fingerprick in the intervention clusters. In the control clusters a blood sample to determine PCR prevalence will be collected 6 months after the first round of blood sampling in that control cluster.	6 months after the first round of PvSeroTAT or 6 months after the first round of blood sampling in the control clusters.
Decrease of mean cluster prevalence of PCR detectable P. vivax blood-stage infections at month 6 after the first round of PvSeroTAT or 6 months after the first round of blood sampling in the control clusters, compared to baseline.		6 months after the first round of PvSeroTAT or 6 months after the first round of blood sampling in the control clusters.
Decrease of mean cluster prevalence of PCR detectable P. vivax blood-stage infections at month 12 after the first round of PvSeroTAT or 12 months after the first round of blood sampling in the control clusters, compared to baseline.		12 months after the first round of PvSeroTAT or 12 months after the first round of blood sampling in the control clusters.
Decrease of mean cluster prevalence of PCR detectable P. vivax blood-stage infections at month 18 after the first round of PvSeroTAT or 18 months after the first round of blood sampling in the control clusters, compared to baseline.		18 months after the first round of PvSeroTAT or 18 months after the first round of blood sampling in the control clusters.
Incidence of clinical cases of P. vivax and P. falciparum malaria during the 6 months after the first round of PvSeroTAT or during the 6 months after the first round of blood sampling in the control clusters.		6 months after the first round of PvSeroTAT or 6 months after the first round of blood sampling in the control clusters.
Incidence of clinical cases of P. vivax and P. falciparum malaria during the 12 months after the first round of PvSeroTAT or during the 12 months after the first round of blood sampling in the control clusters.		12 months after the first round of PvSeroTAT or 12 months after the first round of blood sampling in the control clusters.
Incidence of clinical cases of P. vivax and P. falciparum malaria during the 18 months after the first round of PvSeroTAT or during the 18 months after the first round of blood sampling in the control clusters.		18 months after the first round of PvSeroTAT or 18 months after the first round of blood sampling in the control clusters.
Hemoglobin level at day 3		Day 3
Hemoglobin level at day 7		Day 7
Decrease in Hemoglobin between baseline and day 3 (absolute and proportional)		Day 3
Decrease in Hemoglobin between baseline and day 7 (absolute and proportional)		Day 7
Incidence of potential signs of clinically relevant Haemolysis	25% drop in hemoglobin or hemoglobin<7gram/dL or macroscopic haemoglobinuria or the need for a blood transfusion	7 days
Incidence of Serious Adverse Events		18 months after the first round of PvSeroTAT or 18 months after the first round of blood sampling in the control clusters.
Coverage of serological tests for P. vivax antibodies as proportion of number of individuals per cluster		Day 0 of month 0 or month 6
Proportion of eligible individuals that refuses participation in the study		Day 0 of month 0 or month 6
Proportion of participants with positive P. vivax serology that refuses P. vivax treatment		Day 1 of drug administration
Proportion of serological positive individuals that start primaquine treatment		Day 1 of drug administration
Proportion of individuals that vomits at least once within 1 hour after treatment		Day of start of treatment until day 7 of treatment
Proportion of individuals that vomits twice within 1 hour after treatment.		Day of start of treatment until day 7 of treatment
Proportion of study participants that complete the 14-day or 7-day course of primaquine treatment.		Day of start of treatment until day 7 of treatment

Collaborators and Investigators

• Sponsor: London School of Hygiene and Tropical Medicine
• Collaborators: Institut Pasteur; Institut Pasteur de Madagascar; Armauer Hansen Research Institute (AHRI), Ethiopia
• Investigators: Principal Investigator: Chris Drakeley, London School of Hygiene and Tropical Medicine; Principal Investigator: Michael T White, Institut Pasteur; Principal Investigator: Rindra Randremanana, Institut Pasteur de Madagascar; Principal Investigator: Fitsum G Tadesse, Armauer Hansen Research Institute

Publications and helpful links

Helpful Links

• PvSTATEM project website

Study record dates

Study Major Dates

• Study Start (Actual): May 12, 2025
• Primary Completion (Estimated): April 28, 2027
• Study Completion (Estimated): April 28, 2027

Study Registration Dates

• First Submitted: April 3, 2025
• First Submitted That Met QC Criteria: April 10, 2025
• First Posted (Actual): April 11, 2025

Study Record Updates

• Last Update Posted (Actual): March 24, 2026
• Last Update Submitted That Met QC Criteria: March 19, 2026
• Last Verified: June 1, 2025

More Information

Terms related to this study

• Keywords: serology; Plasmodium vivax; Primaquine; Vivax; G6PD; Cluster randomised trial; PvSeroTAT; PvSTATEM
• Additional Relevant MeSH Terms: Vector Borne Diseases; Mosquito-Borne Diseases; Infections; Protozoan Infections; Parasitic Diseases; Malaria; Malaria, Falciparum; Malaria, Vivax
• Other Study ID Numbers: 29643

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Anonymised demographic data (e.g. age and sex). P. vivax serology results. Clinical parameters such as hemoglobin levels and clinical symptoms. Results of PCR assays for Plasmodium vivax and Plasmodium falciparum.
• IPD Sharing Time Frame: After publication of the manuscripts detailing the results of the study.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No