A Study of the Plasmodium Falciparum Malaria Vaccine Candidate Pfs48/45 in Matrix-M Adjuvant in the UK

A Phase Ia Study to Assess Safety and Immunogenicity of the Plasmodium Falciparum Malaria Vaccine Candidate Pfs48/45 in Matrix-M Adjuvant in Healthy Adults Living in the UK

This is an open label, single-site, first-in-human, dose-escalation Phase Ia study to assess safety and immunogenicity of the Plasmodium falciparum malaria vaccine candidate Pfs48/45 in Matrix-M adjuvant in healthy adults living in the UK

Study Overview

• Status: Terminated
• Conditions: Malaria; Plasmodium Falciparum
• Intervention / Treatment: Biological: Pfs48/45 in Matrix-M

Detailed Description

Volunteers will be recruited into one of three groups (n=8-10 per group) at the Centre for Clinical Vaccinology and Tropical Medicine (CCVTM), Oxford over approximately 12 months. All volunteers will receive three dose of Pfs48/45 in 50 µg Matrix-M, administered intramuscularly and given four weeks apart. Enrolment will be staggered with clinical and safety reviews, follow-up visits and monitoring via a diary card.

• Study Type: Interventional
• Enrollment (Actual): 17
• Phase: Early Phase 1

Contacts and Locations

Study Locations

• United Kingdom
  • Oxford, United Kingdom, OX3 7LE
    • CCVTM, Churchill Hospital, University of Oxford

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years to 41 years (Adult)
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Healthy adult aged 18 to 45 years.
• Able and willing (in the Investigator's opinion) to comply with all study requirements.
• Willing to allow the Investigators to discuss the volunteer's medical history with their GP.
• Volunteers with the potential to become pregnant only: must practice continuous effective contraception for the duration of the study (see section 10.10).
• Agreement to refrain from blood donation for the duration of the study.
• Able and willing to provide written informed consent to participate in the trial

Exclusion Criteria:

• History of clinical malaria (any species).
• Travel to a clearly malaria endemic locality during the study period or within the preceding six months.
• Use of immunoglobulins or blood products (e.g., blood transfusion) in the last three months.
• Receipt of any vaccine in the 30 days preceding enrolment, or planned receipt of any other vaccine within 30 days following each study vaccination, with the exception of COVID-19 vaccines, which should not be received between 14 days before to 7 days after any study vaccination.
• Receipt of an investigational product in the 30 days preceding enrolment, or planned receipt during the study period.
• Concurrent involvement in another clinical trial or planned involvement during the study period.
• Prior receipt of an investigational vaccine likely to impact on interpretation of the trial data, as assessed by the Investigator.
• Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV infection; asplenia; recurrent, severe infections and chronic (more than 14 days) immunosuppressant medication within the past 6 months (inhaled and topical steroids are allowed).
• History of allergic disease or reactions likely to be exacerbated by any component of the vaccine.
• Any history of anaphylaxis in reaction to vaccinations.
• Pregnancy, lactation or intention to become pregnant during the study.
• History of cancer (except basal cell carcinoma of the skin and cervical carcinoma in situ).
• History of serious psychiatric condition that may affect participation in the study.
• Any other serious chronic illness requiring hospital specialist supervision.
• Suspected or known current alcohol abuse as defined by an alcohol intake of greater than 25 standard UK units every week.
• Suspected or known injecting drug abuse in the 5 years preceding enrolment.
• Hepatitis B surface antigen (HBsAg) detected in serum.
• Seropositive for hepatitis C virus (antibodies to HCV) at screening (unless volunteer has taken part in a prior hepatitis C vaccine study with confirmed negative HCV antibodies prior to participation in that study, and negative HCV ribonucleic acid (RNA) PCR at screening for this study).
• Volunteers unable to be closely followed for social, geographic or psychological reasons.
• Any clinically significant abnormal finding on biochemistry or haematology blood tests, urinalysis or clinical examination. In the event of abnormal test results, confirmatory repeat tests will be requested. Procedures for identifying laboratory values meeting exclusion criteria are shown in SOP VC027.
• Any other significant disease, disorder, or finding which may significantly increase the risk to the volunteer because of participation in the study, affect the ability of the volunteer to participate in the study or impair interpretation of the study data.
• Inability of the study team to contact the volunteer's GP to confirm medical history.

Absolute contraindications:

• Anaphylactic reaction following administration of vaccine.
• Pregnancy.

Contraindications at that point in time (may be rescheduled):

• Acute disease at the time of vaccination. (Acute disease is defined as the presence of a moderate or severe illness with or without fever). All vaccines can be administered to persons with a minor illness such as diarrhoea, mild upper respiratory infection with or without low-grade febrile illness, i.e. temperature of ≤37.5°C/99.5°F.
• Temperature of >37.5°C (99.5°F) at the time of vaccination.
• Current COVID-19 infection, defined as ongoing symptoms with positive COVID-19 PCR swab test taken during current illness or positive COVID-19 PCR swab or rapid antigen test within preceding 7 days without symptoms. Vaccinations will be delayed by a minimum of 7 days from the date of the first positive COVID-19 PCR swab or rapid antigen test, as long as symptoms are improving or resolved. It will be at the discretion of the Investigator to withdraw a participant if they develop severe COVID-19 disease.

Study Plan

How is the study designed?

Design Details

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

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Group 1 - low dose; 8-10 volunteers receiving three doses of 10 µg Pfs48/45 in 50 µg Matrix-M on days 0, 28 and 56 via intramuscular injection (IM) in the deltoid region of the arm	Biological: Pfs48/45 in Matrix-M; Three doses of Pfs48/45 in Matrix-M at different doses
Experimental: Group 2 - standard dose; 8-10 volunteers receiving three doses of 50 µg Pfs48/45 in 50 µg Matrix-M on days 0, 28 and 56 via intramuscular injection (IM) in the deltoid region of the arm	Biological: Pfs48/45 in Matrix-M; Three doses of Pfs48/45 in Matrix-M at different doses
Experimental: Group 3 - fractional dose; 8-10 volunteers receiving two doses of 50 µg Pfs48/45 in 50 µg Matrix-M on days 0 and 28, followed by one dose of 10 µg Pfs48/45 in 50 µg Matrix-M on day 56 via intramuscular injection (IM) in the deltoid region of the arm	Biological: Pfs48/45 in Matrix-M; Three doses of Pfs48/45 in Matrix-M at different doses

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Safety and Tolerability of the Pfs48/45 With Matrix-M Vaccine at Various Doses in Healthy Adult Volunteers by Assessing the Occurrence of Solicited Local Reactogenicity Signs and Symptoms for 7 Days Following Each Vaccination	Occurrence of solicited local reactogenicity signs and symptoms for 7 days following each vaccination using e-diaries, clinical review, clinical examination (including observations) and laboratory results	7 days following each vaccination
Safety and Tolerability of the Pfs48/45 With Matrix-M Vaccine at Various Doses in Healthy Adult Volunteers by Assessing the Occurrence of Solicited Systemic Reactogenicity Signs and Symptoms for 7 Days Following Each Vaccination	Occurrence of solicited systemic reactogenicity signs and symptoms for 7 days following each vaccination using e-diaries, clinical review, clinical examination (including observations) and laboratory results.	7 days following each vaccination
Safety and Tolerability of the Pfs48/45 With Matrix-M Vaccine at Various Doses in Healthy Adult Volunteers by Assessing the Occurrence of Unsolicited Adverse Events (AEs) for 28 Days Following the Vaccination	Number of unsolicited adverse events (AEs) for 28 days following the vaccination using e-diaries, clinical review, clinical examination (including observations) and laboratory results	28 days following the vaccination
Safety and Tolerability of the Pfs48/45 With Matrix-M Vaccine at Various Doses in Healthy Adult Volunteers. Assessed Through the Number of Participants With Abnormal Laboratory Test Results	Occurrence of change from baseline laboratory tests	28 days following vaccination
Safety and Tolerability of the Pfs48/45 With Matrix-M Vaccine at Various Doses in Healthy Adult Volunteers Assessed Through the Number of Participants With Serious Adverse Events	Occurrence of serious adverse events will be presented according to local grading scales	Whole duration of the study (8 months following initial trial vaccination)
Safety and Tolerability of the Pfs48/45 With Matrix-M Vaccine at Various Doses in Healthy Adult Volunteers.	Occurrence of AEs of special interest will be presented according to local grading scales and will be described in detail	Whole duration of the study (8 months following initial trial vaccination)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Humoral Immunogenicity of the Pfs48/45 With Matrix-M Vaccine, When Administered to Healthy Adult Volunteers as Assessed by Humoral Responses to the Pfs48/45 Protein	Antibody responses to the Pfs48/45 protein will be assessed through total IgG isotypes and avidity	Days 1, 29, 57, 140 and 240
Cellular Immunogenicity of the Pfs48/45 With Matrix-M Vaccine, When Administered to Healthy Adult Volunteers as Assessed by Cellular Responses to the Pfs48/45 Protein	T cell responses to Pfs48/45 will be assessed by ex vivo enzyme-linked immunospot assays (ELISpot)	Days 1, 29, 57, 140 and 240
Ex Vivo Efficacy of the Pfs48/45 With Matrix-M Vaccine, When Administered to Healthy Adult Volunteers Using Direct Membrane Feeding Assays as Assessed by Transmission-reducing Activity	Transmission-reducing activity	Days 1, 29, 57, 140 and 240
Ex Vivo Efficacy of the Pfs48/45 With Matrix-M Vaccine, When Administered to Healthy Adult Volunteers Using Direct Membrane Feeding Assays as Assessed by Transmission-blocking Activity	Transmission-blocking activity	Days 1, 29, 57, 140 and 240

Collaborators and Investigators

• Sponsor: University of Oxford
• Investigators: Principal Investigator: Angela M Minassian, DPhil FRCP, Center for Clinical Vaccinology and Tropical Medicine, University of Oxford

Study record dates

Study Major Dates

• Study Start (Actual): November 2, 2022
• Primary Completion (Actual): October 19, 2023
• Study Completion (Actual): October 19, 2023

Study Registration Dates

• First Submitted: May 26, 2022
• First Submitted That Met QC Criteria: May 26, 2022
• First Posted (Actual): June 2, 2022

Study Record Updates

• Last Update Posted (Actual): March 28, 2025
• Last Update Submitted That Met QC Criteria: March 11, 2025
• Last Verified: May 1, 2023

More Information

Terms related to this study

• Keywords: Matrix-M; Pfs48/45
• Additional Relevant MeSH Terms: Vector Borne Diseases; Mosquito-Borne Diseases; Infections; Protozoan Infections; Parasitic Diseases; Malaria; Malaria, Falciparum
• Other Study ID Numbers: VAC085

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No