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NCT Number: NCT07468526

An Ultra-short Course of Primaquine for the Radical Cure of Vivax Malaria

Current treatment regimens to prevent relapsing malaria are too long. A shorter higher dose treatment could improve treatment outcomes, but this needs to be balanced against increased risk of side effects. Recent data from a trial in children in Papua New Guinea (PNG) suggests a shortened treatment of 3 days is safe and effective. Our multicentre trial will assess the safety and efficacy of an ultra-short primaquine course. This trial is expected to directly influence global treatment policies.

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Key information

Conditions

Malaria Infections Mosquito-Borne Diseases Parasitic Diseases Protozoan Infections Vector Borne Diseases

Age range

5 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Arba Minch University, Arba Minch, Ethiopia

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Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • P. vivax peripheral parasitaemia as determined by microscopy
  • G6PD normal status (G6PD activity ≥70% of the site specific adjusted male median as determined by the Standard G6PD (SD Bioline, ROK))
  • Fever (temperature ≥37.5°C) or history of fever in the preceding 48 hours,
  • Age ≥5 years
  • Bodyweight ≥14kg
  • Living in the study area and willing to be followed-up for six months

Exclusion criteria

  • Signs or symptoms of severe malaria,
  • Anaemia (defined as Hb <8g/dl) and measured by the Standard G6PD
  • Pregnant or lactating
  • Blood transfusion within the preceding four months
  • Regular or recent use (last month) of tafenoquine, primaquine or dapsone
  • Known hypersensitivity to any of the study drugs

Treatment and study plan

High dose ultra short Primaquine

Drug

High-dose, ultra-short primaquine (PQ3.5): 7mg/kg total dose given as 1mg/kg twice daily over 3.5 days (day 0, 1 and 2 morning and evening doses, and day 3 morning dose) followed by placebo as morning doses on day 4, 5 and 6.

Placebo

Other

Matching placebo administered according to the arm schedule. Morning dose on Days 4-6 for PQ3.5 arm and Evening dose on the first 3 days for PQ 7 arm).

Primary outcomes

  1. Incidence risk of any recurrent vivax parasitaemia within 4 months.

    Time frame: 4 Months

    The incidence risk (time to first event) of any recurrent P. vivax parasitaemia within 4 months as determined by microscopy

Secondary outcomes

  1. The incidence risk of any P. vivax parasitaemia within 6 months.

    Time frame: 6 months

    The incidence risk (time to first event) of any P. vivax parasitaemia within 6 months as determined by microscopy

  2. Incidence of haemoglobin drop >25% to <7g/dl within 14 days of treatment.

    Time frame: 0-14 days

    Number of participants experiencing a haemoglobin decrease of >25% from baseline resulting in Hb<7g/dl

  3. Incidence of moderate anaemia within 14 days after starting primaquine

    Time frame: 0-14 days

    Number of participants developing haemoglobin >=5g/dl and <7g/dl within 14 days after treatment initiation

  4. Incidence of severe anaemia within 14 days after starting Primaquine

    Time frame: 0-14 days

    Number of participants developing haemoglobin <5g/dl within 14 days of treatment initiation.

  5. • The proportion of patients requiring blood transfusion within the 6 months follow up period.

    Time frame: 6 months

    Participants requiring transfusion due to haemolysis or severe anaemia

  6. The incidence risk of symptomatic P. vivax parasitaemia within 4 months.

    Time frame: 4 months

    The incidence risk (time to first event) of symptomatic P. vivax parasitaemia within 4 months as determined by microscopy.

  7. Proportion of adverse events within 14 days.

    Time frame: 14 days

    The number and proportion of adverse events within 14 days after start of treatment

  8. The number and proportion of serious adverse events.

    Time frame: 6 Months

    The number and proportion of serious adverse events.

Study contacts

Contact information is provided by the study sponsor or research team.

Hellen Mnjala, MSc

CONTACT

[email protected]

+61889468675

Kamala Thriemer, Professor

CONTACT

[email protected]

+61889468644

Sponsors and collaborators

Lead sponsor

Menzies School of Health Research

Other

Collaborators

  • Aga Khan University
  • Arba Minch University
  • Curtin University
  • Jimma University
  • Papua New Guinea Institute of Medical Research
  • PathWest Laboratory Medicine WA
  • Universitas Sumatera Utara
  • University of Melbourne

Registry information

Official study title

An Ultra-short Course of Primaquine for the Radical Cure of Vivax Malaria (PRIMUS)

Acronym: PRIMUS

Important dates

Study start
2026
Primary completion
2027
Study completion
2028
First posted
Mar 12, 2026
Registry last updated
Mar 12, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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