A Safety, Immunogenicity and Efficacy Study of PvRII/Matrix-M in Healthy Thai Adults Living in Thailand ( MIST3 )

Starting soon · Phase 2 · Has a placebo group

Conditions studied: Plasmodium Vivax Infection, Malaria Vaccine

In brief

This project is the third part of a 5-year research program entitled "Malaria Infection Studies in Thailand (MIST)" and known as MIST3. MIST3's primary objectives are to assess the safety of the PvRII/Matrix-M vaccine candidate in healthy adult Thai volunteers and to establish whether the PvRII/Matrix-M vaccine can demonstrate a reduced parasite multiplication rate in vaccinated volunteers compared to a controlled group (placebo vaccine) in a blood-stage controlled human malaria infection model. This study will recruit up to 36 eligible healthy volunteers aged 20-55 in Thailand at the Faculty of Tropical Medicine, Mahidol University. Eighteen volunteers will receive three doses of the PvRII/Matrix-M candidate vaccine, and 18 volunteers will receive three doses of the placebo vaccine. Safety and immunogenicity will be evaluated after each dose as per protocol. Approximately four weeks after receiving the third vaccination, 24 volunteers will undergo blood-stage CHMI with Plasmodium vivax. The volunteers will be monitored closely as in-patients in the Hospital for Tropical Diseases and treated according to the Research Proposal Submission Form. This study is funded by the UK Wellcome Trust. The grant reference number are Oxford/MORU: 212336/Z/18/Z and 212336/Z/18/A, and Mahidol University: 212336/A/18/Z and 212336/A/18/A

Key facts

Study ID

NCT05380388

Run by

University of Oxford

People needed

36

Starts

2027-01-01

Expected to finish

2027-12-30

Last updated by the study team

2026-03-24

Who can join

Age: 20 and older, up to 55. Sex: any. Healthy volunteers: accepted.

You may qualify if…

• Healthy Thai adults aged 20 to 55 years
• Minimum educational level of high school or equivalent
• Red blood cells positive for the Duffy antigen/chemokine receptor (DARC)
• Women only: Must practice continuous effective contraception for the duration of the study period until 3 months post-challenge.
• Agreement to refrain from blood donation during the study and for 1 year after the initiation of antimalarial treatment.
• Willing to be admitted to the Hospital for Tropical Diseases for clinical monitoring as required by the protocol until antimalarial treatment is completed and their symptoms are settling, willing to take a curative antimalarial treatment following CHMI, and willing to reside in Bangkok and its vicinity for 2 months after malarial treatment initiation.
• Able to read and write in Thai.
• Provide written informed consent to participate in the trial
• Answer all questions on the informed consent quiz correctly
• Completed COVID-19 vaccination with 2 doses of any WHO-approved vaccine

You may not qualify if…

• Positive malaria qPCR OR malaria film prior to vaccination and challenge
• Presence of any medical condition (either physical or psychological) that, in the judgment of the investigator, would place the participant at undue risk (including the history of clinically significant contact dermatitis) or interfere with the results of the study (e.g., underlying cardiac, renal, hepatic or neurological disease; severe malnutrition; congenital defects or febrile condition)
• Presence of chronic disease or chronic use of medication
• Prior receipt of other investigational vaccine which is likely to impact the interpretation of the trial data as assessed by the Investigator.
• Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV infection, asplenia, history of splenectomy, recurrent severe infections, and chronic infection
• Immunosuppressant medication within the past 6 months preceding enrolment (D0) or plan to use during the study (inhaled and topical steroids are allowed)
• History of allergic disease or reactions likely to be exacerbated by malaria infection
• Female participant who is pregnant as evidenced by positive beta-human chorionic gonadotropin (β-HCG) test, or who is lactating or planning pregnancy during the course of the study.
• Contraindications to the use of antimalarial treatment (e.g., chloroquine, atovaquone/proguanil, or dihydroartemisinin/piperaquine)
• Use of medications known to have potentially clinically significant interaction with the antimalarial drugs that will be used in this study (chloroquine, atovaquone/proguanil, or dihydroartemisinin/piperaquine)
• History of cardiac arrhythmia, including clinically relevant bradycardia or Known existing positive family history in both 1st AND 2nd-degree relatives < 50 years old for cardiac disease
• Family history of congenital QT prolongation or sudden death
• Any clinical condition, including using medications known to prolong the QT interval or screening electrocardiogram (ECG), demonstrates a QTc interval ≥ 450 ms.
• Suspected or known history of alcohol abuse or history of drug abuse.
• Concurrently participating in another clinical study, at any time during the study period
• Positive hepatitis B surface antigen or seropositive for hepatitis C virus, or HIV
• Finding on safety laboratory values as defined below:
• Abnormal ALT [>upper normal range]
• Abnormal serum creatinine [>upper normal range]
• Clinically significant abnormalities in corrected calcium and magnesium blood levels
• Haemoglobin < 11 g/dL
• Blood group Rhesus negative
• Blood incompatibility to the inoculum
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine
• Any history of anaphylaxis in reaction to vaccinations

Where it is running

• Faculty of Tropical Medicine — Bangkok, Thailand

Full record on ClinicalTrials.gov

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