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A Challenge Study to Assess the Safety, Immunogenicity and Efficacy of a Malaria Vaccine Candidate

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT02927145
Recruitment Status : Completed
First Posted : October 6, 2016
Last Update Posted : November 18, 2019
Sponsor:
Information provided by (Responsible Party):
University of Oxford

Brief Summary:

This is an open-label, multi-centre Phase I/IIa dose escalation blood-stage malaria CHMI trial to assess the safety, immunogenicity and efficacy of the candidate malaria vaccine RH5.1/AS01. All volunteers recruited will be healthy, malaria naïve adults aged between 18 and 45 years.

Volunteers will be recruited and vaccinated at the CCVTM, Oxford; Guys and St Thomas' NIHR CRF, London; and the NIHR WTCRF, Southampton for the Phase Ia part of the trial, and at the CCVTM, Oxford and Guys and St Thomas' NIHR CRF, London for the Phase IIa stage.


Condition or disease Intervention/treatment Phase
Malaria Biological: RH5.1/ ASO1 Phase 1 Phase 2

Detailed Description:

This is a descriptive phase I trial to assess the safety and immunogenicity of the RH5.1/AS01 vaccine in healthy volunteers at different doses, and to establish whether the RH5.1/AS01 vaccine can demonstrate a reduced parasite multiplication rate in vaccinated subjects compared to infectivity controls in a blood-stage controlled human malaria infection model.

There will be 6 study groups across two phases of the trial, with a total of 66 - 78 volunteers.

Vaccination of groups will be sequential from Group 1 to Group 3. Group 3 and 4 can be recruited simultaneously. Volunteers will be able to choose which group they are allocated to.

The vaccination dose for Group 5 has been decided following the analysis of safety and exploratory immunology assays from Groups 1, 2 and 4. They will undergo blood-stage CHMI 2 weeks after the final vaccination and will be followed up until approximately 6 months after the final vaccination.

Group 6 volunteers will be infectivity controls, so will not receive any vaccinations.

Volunteers will be recruited and undergo screening visits, vaccination and clinic visits post-vaccination at their local trial site. Procedures will be performed on the visit time points indicated in the schedule of attendances.. Additional procedures or laboratory tests may be performed, at the discretion of the Investigators.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 75 participants
Allocation: Non-Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Prevention
Official Title: A Phase I/IIa Clinical Trial to Assess the Safety, Immunogenicity and Efficacy of the Blood-stage Plasmodium Falciparum Malaria Vaccine Candidate RH5.1/AS01
Actual Study Start Date : October 17, 2016
Actual Primary Completion Date : June 27, 2019
Actual Study Completion Date : June 27, 2019

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Malaria

Arm Intervention/treatment
Active Comparator: Group 1-Phase Ia
The study is designed to assess a 'standard' protein-in-adjuvant vaccination regimen- 2µg RH5.1/ 0.5mL AS01- of 3 doses given four weeks apart, with dose escalation to assess the best dose in healthy adults.
Biological: RH5.1/ ASO1

The RH5.1 protein consists of the entire full-length ectodomain of the PfRH5 antigen (amino acids E26 - Q526) with the sequence based on the 3D7 clone of P. falciparum.

The AS01 adjuvant system has been developed and manufactured by GlaxoSmithKline (GSK) Biologicals and is presented as a liquid solution in a monodose glass vial. AS01 is a liposome-based Adjuvant System with a specific aim to improve cell-mediated immunity.


Active Comparator: Group 2- Phase Ia

The dose used will be- 10µg RH5.1/ 0.5mL AS01. The total number of volunteers recruited to Groups 1 and 2 will be decided based on the immunogenicity of the vaccines at the 2 µg and 10 µg doses.

If the doses are immunogenic the groups (1 and 2) will be recruited to a total of 12 volunteers.

Biological: RH5.1/ ASO1

The RH5.1 protein consists of the entire full-length ectodomain of the PfRH5 antigen (amino acids E26 - Q526) with the sequence based on the 3D7 clone of P. falciparum.

The AS01 adjuvant system has been developed and manufactured by GlaxoSmithKline (GSK) Biologicals and is presented as a liquid solution in a monodose glass vial. AS01 is a liposome-based Adjuvant System with a specific aim to improve cell-mediated immunity.


Active Comparator: Group 3-Phase Ia

Group 3 will receive 50µg RH5.1/ 0.5mL AS0

The ultimate aim is to assess the safety and immunogenicity of giving the 'standard' first two doses of the vaccine followed by a delayed fractional dose (10 µg).

Biological: RH5.1/ ASO1

The RH5.1 protein consists of the entire full-length ectodomain of the PfRH5 antigen (amino acids E26 - Q526) with the sequence based on the 3D7 clone of P. falciparum.

The AS01 adjuvant system has been developed and manufactured by GlaxoSmithKline (GSK) Biologicals and is presented as a liquid solution in a monodose glass vial. AS01 is a liposome-based Adjuvant System with a specific aim to improve cell-mediated immunity.


Active Comparator: Group 4-Phase Ia
Group 3 and 4 will be recruited simultaneously. The dose of vaccine for this group is same as that of 3 (50µg RH5.1/ 0.5mL AS01)
Biological: RH5.1/ ASO1

The RH5.1 protein consists of the entire full-length ectodomain of the PfRH5 antigen (amino acids E26 - Q526) with the sequence based on the 3D7 clone of P. falciparum.

The AS01 adjuvant system has been developed and manufactured by GlaxoSmithKline (GSK) Biologicals and is presented as a liquid solution in a monodose glass vial. AS01 is a liposome-based Adjuvant System with a specific aim to improve cell-mediated immunity.


Active Comparator: Group 5-Phase IIa
The vaccination dose for Group 5 was decided following the analysis of safety and exploratory immunology assays from Groups 1, 2 and 4. The dose of vaccine for this group is the same as that of group 2 (10µg RH5.1/ 0.5mL AS01).
Biological: RH5.1/ ASO1

The RH5.1 protein consists of the entire full-length ectodomain of the PfRH5 antigen (amino acids E26 - Q526) with the sequence based on the 3D7 clone of P. falciparum.

The AS01 adjuvant system has been developed and manufactured by GlaxoSmithKline (GSK) Biologicals and is presented as a liquid solution in a monodose glass vial. AS01 is a liposome-based Adjuvant System with a specific aim to improve cell-mediated immunity.


No Intervention: Group 6-Phase IIa

Group 6 volunteers will be infectivity controls, so will not receive any vaccinations.

Groups 5 and 6 will only be recruited once at least 6 volunteers in Group 4 have completed all vaccinations.

Active Comparator: Group 7-Phase IIa
Group 7 are Group 5 volunteers who will receive a fourth dose of IMP (10µg RH5.1/ 0.5mL AS01)
Biological: RH5.1/ ASO1

The RH5.1 protein consists of the entire full-length ectodomain of the PfRH5 antigen (amino acids E26 - Q526) with the sequence based on the 3D7 clone of P. falciparum.

The AS01 adjuvant system has been developed and manufactured by GlaxoSmithKline (GSK) Biologicals and is presented as a liquid solution in a monodose glass vial. AS01 is a liposome-based Adjuvant System with a specific aim to improve cell-mediated immunity.


No Intervention: Group 8 -Phase IIa
Group 8 are infectivity controls who were originally in Group 6.
No Intervention: Group 9 -Phase IIa
Group 9 are new infectivity controls



Primary Outcome Measures :
  1. efficacy of the RH5.1/AS01 vaccine by demonstrating a reduced PMR in vaccinated subjects compared to infectivity controls against 3D7 clone parasites in a CHMI model. [ Time Frame: 8 months ]
    PCR-derived parasite multiplication rate (PMR) will be the primary efficacy endpoint for the Phase IIa stage of the trial, and comparison of the endpoint between the Groups 5 and 6 will constitute the primary analysis for efficacy.

  2. the safety of RH5.1/AS01 in healthy malaria-naïve adults in the UK. [ Time Frame: 8 months ]
    The specific endpoints for safety and reactogenicity will be actively and passively collected data on adverse events.

  3. the in vitro growth inhibition activity (GIA) against 3D7 clone P. falciparum parasites of IgG purified from the serum of vaccinees. [ Time Frame: 8 months ]
    The specific endpoints for GIA in vitro will be assessed from a titration of the purified IgG in the assay.


Secondary Outcome Measures :
  1. the humoral immunogenicity of RH5.1/AS01 using different vaccine doses and vaccination regimens. [ Time Frame: 8 months ]
    Antibody responses to the RH5.1 protein generated by vaccination

  2. the cellular immunogenicity of RH5.1/AS01 using different vaccine doses and vaccination regimens. [ Time Frame: 8 months ]
    T cell responses to the RH5.1 protein generated by vaccination

  3. immunological readouts for association with a reduced parasite multiplication rate. [ Time Frame: 8 months ]
    Statistical correlation between anti-RH5 antibody responses induced by the RH5.1 vaccine and PMR.



Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.


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Ages Eligible for Study:   18 Years to 45 Years   (Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Healthy adults 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 General Practitioner (GP).
  • For females only, willingness to practice continuous effective contraception (see below) during the study and a negative pregnancy test on the day(s) of screening and vaccination, and on the day prior to blood-stage CHMI, and prior to the start of antimalarial treatment for Group 5 and 6 volunteers.
  • Agreement to refrain from blood donation during the course of the study.
  • Provide written informed consent.

Additional Inclusion Criteria for Groups 5 - 6

  • Agreement to permanently refrain from blood donation, as per current UK Blood Transfusion and Tissue Transplantation Services guidelines.
  • Reachable (24 hours a day) by mobile phone during the period between CHMI and completion of antimalarial treatment.
  • Willingness to take a curative anti-malaria regimen following CHMI.
  • Answer all questions on the informed consent questionnaire correctly.

Exclusion Criteria:

  • Participation in another research study involving receipt of an investigational product in the 30 days preceding enrolment, or planned use during the study period.
  • Prior receipt of an investigational malaria vaccine or any other investigational vaccine likely to impact on interpretation of the trial data.
  • Any medical condition that in the judgment of the investigator would make intramuscular (IM) injection unsafe.
  • Administration of immunoglobulins and/or any blood products within the three months preceding the planned administration of the vaccine candidate.
  • Any confirmed or suspected immunosuppressive or immunodeficient state, including HIV infection; asplenia; recurrent, severe infections and chronic (more than 14 days) immunosuppressant medication during the period starting six months prior to the first vaccine dose. For corticosteroids, this will mean prednisone 20 mg/day (for adult subjects), or equivalent. Inhaled and topical steroids are allowed.
  • Administration of long-acting immune-modifying drugs at any time during the study period (e.g. infliximab).
  • Chronic use of antibiotics with antimalarial effects (e.g. tetracyclines for dermatologic patients, sulfa for recurrent urinary tract infections, etc.).
  • History of malaria chemoprophylaxis within 60 days prior to vaccination.
  • History of allergic disease or reactions likely to be exacerbated by any component of the vaccine.
  • Any history of anaphylaxis in relation to vaccination.
  • Pregnancy, lactation or willingness/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 likely to 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 42 units every week.
  • Suspected or known injecting drug abuse in the 5 years preceding enrolment.
  • Seropositive for hepatitis B surface antigen (HBsAg).
  • Seropositive for hepatitis C virus (antibodies to HCV).
  • History of clinical malaria (any species).
  • Travel to a malaria endemic region during the study period or within the previous six months.
  • Any clinically significant abnormal finding on screening biochemistry or haematology blood tests or urinalysis.
  • 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 and safety to participate.

Additional exclusion criteria for groups 5 - 6

  • Use of systemic antibiotics with known antimalarial activity within 30 days of CHMI (e.g. trimethoprim-sulfamethoxazole, doxycycline, tetracycline, clindamycin, erythromycin, fluoroquinolones and azithromycin).
  • History of sickle cell anaemia, sickle cell trait, thalassaemia or thalassaemia trait or any haematological condition that could affect susceptibility to malaria infection.
  • Use of medications known to cause prolongation of the QT interval AND existing contraindication to the use of Malarone.
  • Use of medications known to have a potentially clinically significant interaction with Riamet AND Malarone.
  • Contraindications to the use of all three proposed anti-malarial medications; Riamet, Malarone and Chloroquine.
  • Any clinical condition known to prolong the QT interval.
  • Family history of congenital QT prolongation or sudden death.
  • Positive family history in 1st and 2nd degree relatives < 50 years old for cardiac disease.
  • History of cardiac arrhythmia, including clinically relevant bradycardia.
  • Volunteer unable to be closely followed for social, geographic or psychological reasons.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT02927145


Locations
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United Kingdom
Guys and St Thomas' NIHR CRF
London, United Kingdom
Nihr Wtcrf
Southampton, United Kingdom
Sponsors and Collaborators
University of Oxford
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Responsible Party: University of Oxford
ClinicalTrials.gov Identifier: NCT02927145    
Other Study ID Numbers: VAC063
First Posted: October 6, 2016    Key Record Dates
Last Update Posted: November 18, 2019
Last Verified: August 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided
Additional relevant MeSH terms:
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Malaria
Protozoan Infections
Parasitic Diseases