A Phase 2 interventional study of R21/Matrix-M1 and Saline and R21/Matrix-M1 in Healthy Women of Child Bearing Potential, sponsored by University of Oxford. Active, not recruiting at 1 site in Mali. Open to female participants aged 18 Years to 35 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-02-23.
Sponsored by University of Oxford · Phase 2, Interventional, and Prevention
This will be a double-blind, individually randomised trial, to assess the safety, tolerability, immunogenicity, and protective efficacy of two and three doses of the R21/Matrix-M1 malaria vaccine or placebo given at 4 week intervals in healthy women of childbearing potential (WOCBP), who are on pregnancy prevention during vaccination, but report plans to become pregnant in the near future.
Participants will be randomised in Year 1 into three groups in a 1:1:1 ratio:
Initial follow-up will be for two years after dose three, with an efficacy analysis at 6, 12, 18 and 24 months after dose 3.
Participants will be monitored for safety, tolerability, immunogenicity, and malaria infection during the follow-up period.
Participants will also be monitored for pregnancy over 12 months post primary and booster vaccination and those who become pregnant will be followed during their pregnancy and for 1 year post-delivery (as well as their offspring) for safety and malaria infection
The design will be a double blind, placebo-controlled study. Malian adult WOCBP between 18 and 35 years of age who consent to participate will be randomised to receive R21/Matrix-M1vaccine or normal saline to assess the safety, immunogenicity and protective efficacy of R21/Matrix-M1 Vaccine.
Randomisation and Study Arms Consenting participants who have satisfied all the eligibility criteria and completed the baseline assessment will be individually randomised within the study groups using an electronic randomisation system into three arms in a 1:1:1 ratio.
Participants will be assessed for safety, immunogenicity and efficacy for 12 months. After 12 months non-pregnant participants in arms 1 and 2, will be randomised in a 1:1 ratio; half in each of these two arms will receive a booster dose of R21/Matrix-M1 vaccine and half will receive a placebo injection (normal saline) and be followed up for an additional 12 months.
All injections will be administered intramuscularly in the deltoid region, preferably of the non-dominant arm. Post third injection, participants will be followed through the malaria transmission (rainy) season, approximately 6 months, and then the ensuing dry season for an additional 6 months. Participants will be monitored for safety, immunogenicity, and protective efficacy (malaria infection) during the follow-up period.
For any women who become pregnant during the two-year period (first year and second year) of the trial, follow up will continue through the end of pregnancy, and any viable newborns/infants and their mothers will be followed through the first year of life.
University of Oxford is the lead sponsor of 812 studies on the registry; 119 are open to participants now.
Counted across the registry records on this site, refreshed daily.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Exclusion Criteria:
systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, Sjögren's syndrome, or autoimmune thrombocytopenia.
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Childbearing potential
Able to become pregnant: from the first period until menopause, unless permanently unable to through surgery (removal of the womb, or of both ovaries or both fallopian tubes).
Criteria for people of childbearing potential usually ask for a negative pregnancy test and for contraception during the study and for a time after it.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hemoglobin (Hb)
The protein in red blood cells that carries oxygen. A low level is anaemia, which can cause tiredness and breathlessness. Measured in g/dL or g/L (9 g/dL is 90 g/L).
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Platelets
Blood cells that help blood clot. Too few raises the risk of bleeding and bruising. A usual adult range is about 150–400 × 10⁹/L (150,000–400,000 per µL); each lab has its own reference range.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ALT and AST (liver enzymes)
Two enzymes measured in a routine blood test of the liver. Higher levels can mean the liver is under strain or damaged. SGPT and SGOT are older names for ALT and AST.
Criteria usually give a limit as a multiple of the upper limit of normal (ULN), often higher when cancer has spread to the liver.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
ULN (upper limit of normal)
The top of the normal range for a blood test, as set by the laboratory that runs it. Each lab prints its own range next to your result.
“≤ 2.5 × ULN” means the result can be up to two and a half times that top value.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Autoimmune disease
A condition in which the immune system attacks the body’s own tissues, such as rheumatoid arthritis, lupus, psoriasis, type 1 diabetes or inflammatory bowel disease.
Immunotherapy studies often leave out active autoimmune disease, and some name exceptions, such as thyroid disease on replacement hormone. Check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Investigational drug or device
A drug or device being studied in a clinical trial.
It may be new, or already approved and being studied for another use, dose or form. Criteria often leave out people who took part in another study of one within a recent period, commonly 30 days or five half-lives.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Corticosteroids (steroids)
Anti-inflammatory medicines such as prednisone, prednisolone and dexamethasone — not the anabolic steroids used for muscle.
Studies differ in what they allow: check which steroid medicines, routes (tablets, injections, creams, inhalers, eye drops) and doses this study accepts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Immunosuppression
A weakened immune system. It can come from an illness, such as HIV or some blood cancers, or from medicines that turn the immune system down, for example after an organ transplant or for an autoimmune disease; steroids at higher doses count.
Read whether the line is about a condition or about medicines, and which medicines and doses it means.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Live vaccines
Vaccines made with a weakened form of the germ, such as measles–mumps–rubella (MMR), chickenpox and yellow fever. They can be risky when the immune system is weakened. Flu injections are not live; the nasal flu spray is.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants receiving three doses of R21/Matrix-M1 malaria vaccine at months 0, 1 and 2.
Biological: R21/Matrix-M1
Participants receiving normal saline (placebo) at month 0 and two doses of R21/Matrix-M1 malaria vaccine at month 1 and 2
Biological: Saline and R21/Matrix-M1
Participants receiving three doses of normal saline (placebo) at months 0, 1 and 2
Other: Sterile isotonic (0.9%) normal saline
10 µg of R21 and 50 µg of Matrix-M1
Saline and 10 µg of R21 and 50 µg of Matrix-M1
Also known as: R21/Matrix-M1
Saline
Also known as: Placebo
Incidence of local and systemic solicited adverse events (AEs)
\- Incidence of local and systemic solicited adverse events (AEs) graded by severity.
Time frame: Within 7 days after each vaccine administration and over 6 months post third vaccination
Number of participants with P falciparum infection
P. falciparum blood stage infection defined as time to first positive blood smear
Time frame: Over 6 months post third vaccination
Assessment of safety and tolerabilty
* Occurrence of unsolicited adverse events 28 days follow-up following the vaccination. * Occurrence of serious adverse events for the whole study duration including in women who become pregnant.
Time frame: Through study completion, an average of 26 months
Anti-CSP antibody concentrations
Immunological assessment measuring the anti-CSP antibody concentrations in healthy Malian women of child bearing potential
Time frame: Through study completion. Timepoints: baseline, days 70, 84, 140, 196, 434, 448, 504 and 560
Rate of P.falciparum infection during pregnancy
P. falciparum blood stage infection defined as time to first positive blood smear during pregnancy
Time frame: Over 9-months pregnancy
Rate of P.falciparum infection
P. falciparum blood stage infection defined as time to first positive blood smear.
Time frame: Over 12-, 18- and 24-months post third vaccination
Exploratory - number of participants with negative obstetric outcome
negative maternal obstetric outcomes described as gestational diabetes, preterm premature rupture of membranes, third trimester hemorrhage, placental abruption, emergency C-section, post-partum hemorrhage, chorioamnionitis,miscarriage/stillbirth, intrauterine growth restriction, hypertensive diseases in pregnancy, preterm delivery
Time frame: Over 9-months pregnancy
Exploratory - Immunology
Antibody levels to VAR2CSA
Time frame: Through study completion, an average of 26 months
Exploratory - Efficacy-Number of participants with symptomatic malaria
\- Symptomatic malaria defined as clinical or symptomatic malaria for this study is defined as the presence of asexual P. falciparum parasites at any parasitemia level and/or positive rapid diagnostic test with either an axillary temperature of 37.5 °C or more or one or more of the following symptoms: headache, myalgia, arthralgia, malaise, nausea, dizziness, or abdominal pain and will be reported as an AE
Time frame: Through study completion, an average of 26 months
Exploratory - Efficacy-Number of participants with subclinical malaria infection
P. falciparum qPCR may be performed from all scheduled visits with a malaria blood smear noted to capture infections that remain below the detection limit for microscopy
Time frame: Through study completion, an average of 26 months
Exploratory - Efficacy-Number of participants with gametocytemia
Blood smear microscopy to detect presence of P. falciparum gametocytes
Time frame: Through study completion, an average of 26 months
Exploratory - Efficacy-Number of participants with non P. falciparum malaria infection
Blood smear microscopy to detect presence of non-P. falciparum parasites
Time frame: Through study completion, an average of 26 months
Exploratory - Efficacy-Number of infants with P falciparum infection
P. falciparum blood stage infection at blood smear during infancy
Time frame: From birth until 12 months of age
Exploratory - Efficacy-number of participants with P falciparum placental infection
\- P. falciparum placental infection defined as any positive placental blood smear for P. falciparum.
Time frame: Through study completion, an average of 26 months
Exploratory - Number of babies with negative outcome
negative neonatal outcome defined as neonatal death, low birth weight, small for gestational age, major malformations, hypoxic-ischemic encephalopathy, microcephaly, and APGAR score \<7
Time frame: Up to 1 year
Plan to share: No
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