A Phase I/IIa sporozoite challenge study to assess the safety, immunogenicity and protective efficacy of adjuvanted R21, administered in different dose Schedules in healthy UK volunteers

An open label, partially blinded clinical trial in which healthy volunteers will be administered experimental malaria vaccines. There will be seven experimental groups of volunteers, of which five receive vaccination with the novel malaria vaccine candidate, R21, in combination with the vaccine adjuvant, Matrix M.

Arms 1a & 1b receive vaccines at 3 vaccinations at 4 week intervals and a booster vaccination approximately 12 months after the first vaccination.

Arms 2a & 2b receive 3 vaccinations at 0, 4 and 24 weeks. The protected volunteers in 2a from the first malaria challenge, VAC072A, will receive a booster vaccination 28 days before the rechallenge, VAC072B.

Arms 3a and 3b receive 3 vaccinations at 0, 4 and 8 weeks. The protected volunteers in 3a from the first malaria challenge, VAC072A, will receive a booster vaccination 28 days before the rechallenge, VAC072B.

Arms 4a and 4b will receive 3 vaccinations at 0, 4 and 24 weeks. The third dose is fractional. Volunteers then have the option to be challenged 28 days after final vaccination.

Group 5 will receive 3 vaccinations at 0, 4 and 24 weeks. The third dose is fractional. Volunteers then have the option to be challenged 28 days after final vaccination.

Groups 6 & 7 are control groups and will receive controlled human malaria infection (CHMI)

Healthy volunteers will be recruited in England across four research sites in Oxford, London, and Southampton.

NCT number: NCT03970993

Study type: Interventional

Enrollment: 78 participants

Allocation: Non-Randomized

Intervention model: Parallel Assignment

Masking: None (Open Label)

Primary purpose: Prevention

Clinical trial registration

Product Development
Vaccines (Immune Correlates)

Jun 2019 — Aug 2021

United Kingdom

Multi-Stage Malaria Vaccine Consortium (MMVC): A four-strike vaccine against malaria