Assessment of the Malaria Vaccine Candidate SumayaVac-1 in Healthy Adults Aged 18-45 Years Living in a Malaria Endemic Country

Study Overview
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Brief Summary
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Malaria remains a major infectious disease causing a heavy burden of mortality and morbidity in populations living in tropical and subtropical regions. Large, international research efforts have been invested into the development of anti-malaria vaccination strategies, however, currently there is only one malaria vaccine approved for use in the pediatric population, which provides a moderate and short-lived protection. Therefore, there is a need to develop a malaria vaccine that will be essential to further strengthen malaria control measures in future. A Phase Ia trial with the same IMP (SumayaVac-1 vaccine developed using a full-length recombinant MSP-1 administered along with the adjuvant GLA-SE) in Caucasians in Heidelberg, Germany, proved to be well tolerated and safe. However, a Phase Ib clinical trial on healthy participants residing in a malaria endemic country would be essential to evaluate the safety and reactogenicity in the target population. The project aims to investigate the safety, reactogenicity, immunogenicity of the candidate malaria vaccine, SumayaVac-1 (SUM-101) in 40 healthy participants (men and women) of African origin in Bagamoyo, Tanzania. It will also employ the Controlled Human Malaria Infection model to evaluate the ability of this vaccine candidate to induce immune responses that prevent malaria parasites from getting into the red blood cells thereby preventing development of malaria.

Detailed Description
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Objectives: To evaluate in healthy adults of African origin previously exposed to the malaria parasite receiving SumayaVac-1 (SUM-101) versus rabies control (Verorab®) vaccine: Primary Objectives Safety and reactogenicity of SumayaVac-1 (SUM-101). Immunogenicity of SumayaVac-1 (SUM-101). Secondary Objectives • The relationship of SumayaVac-1 (SUM-101) vaccine-induced antibody levels, in vitro effector functions and isotype distribution with asexual blood stage parasite growth rates after homologous controlled human malaria infection (CHMI). Exploratory Objectives Comparison of SumayaVac-1 (SUM-101) induced immunoglobulin isotype distribution and duration between malaria pre-exposed and malaria naïve participants from the previous Phase Ia study in Heidelberg. Fine scale epitope mapping of SumayaVac-1 (SUM-101) specific antibodies, including specific CD4+ and CD8+ T-cell epitopes using peptide arrays, to investigate the association between cellular immune response with humoral seroconversion and investigate the potential association with protection after homologous CHMI. Comparison of SumayaVac-1 (SUM-101) induced cellular immunity between malaria pre-exposed and malaria naïve participants from the previous Phase Ia study in Heidelberg. Investigation of the B- and T-Cell repertoire before and after SumayaVac-1 (SUM-101) vaccination, as well as after homologous CHMI. Integrated transcriptome and immunoglobulin gene repertoire analyses of MSP-1 specific B-cells using single-cell technologies. Glycosylation patterns of MSP-1 specific functional antibodies. Investigate off-target IgG and IgM repertoire after SumayaVac-1 (SUM-101) vaccination using immunoproteomics and their association with protection after homologous CHMI. Investigate the structure of MSP-1 protein bound to functional antibodies by cryo-electron tomography to map conformational epitopes. Mechanisms of malaria specific antibody diversity generation, post-translational modification of antibodies, and B- and T-cell memory generation and maintenance. Human and parasite transcriptome in peripheral blood during early stage asexual blood stage parasitemia after homologous CHMI. The quality and quantity of peripheral blood γδ T-cell responses in participants with or without homologous CHMI (all 40 participants). Liver to blood inoculum size of the CHMI-induced parasites after homologous CHMI (25 participants that undergo homologous CHMI). Study Design: This is a randomised, controlled, double-blind, parallel group, single center Phase Ib trial to assess the safety, reactogenicity, and immunogenicity and parasite growth rates after homologous CHMI of SumayaVac-1 (SUM-101) in healthy, malaria-exposed adults of African origin aged 18-45 years. The study is divided in two parts: Vaccinations (Part 1) In total, 40 participants will be enrolled (male and female). 20 participants will be randomised to receive three monthly inoculations (on D0, D28 and D56) with the investigational product, SumayaVac-1 (SUM-101), and 20 participants will be randomised to receive the registered rabies vaccine, Verorab®, as controls. For operational reasons the participants will be split in two groups of 20 participants. Group 1 will have a sentinel subgroup (2 SumayaVac-1 (SUM-101) & 1 Verorab® rabies vaccine) with a 48 hours safety surveillance period before the remaining 17 participants (8 SumayaVac-1 (SUM-101) & 9 Verorab® rabies vaccine) of the group 1 receive their 1st vaccination. Group 2 will be composed of 20 participants (10 SumayaVac-1 (SUM-101) & 10 Verorab® rabies vaccine). All visits in group 2 will be shifted by 3 weeks compared to group 1 to create minimal overlap of study-related activities. After each vaccination (done on D0, D28 and D56), the participants will remain at the facility for 2 hours prior to their discharge for home. The participant will be called daily by phone (or home visits if required) until 6 days post vaccination for follow-up. For all participants, vaccination follow-up visits at the site will occur at 7, 14 and 28 days after each vaccination. CHMI (Part 2) In total, 25 participants (15 SumayaVac-1 (SUM-101) & 10 Verorab® vaccinated, selected randomly from the overall 40 participants) will undergo homologous CHMI with attenuated sporozoites 4 weeks after the 3rd vaccination. For operational reasons, the participants will remain in the two separate groups defined in the vaccination part. After the CHMI, the participant will stay for 2 hours at the facility before being discharged. The participant will be called daily by phone (or home visits if required) until 4 days post CHMI for follow-up. 5 days after CHMI, participants will return to the site and be admitted to the ward for closer observation during the period when parasitemia could possibly be detected. The participant will remain in confinement at the site until he/she is considered positive for malaria or reaches 28 days post CHMI. All participants will then receive anti-malarial treatment (for 3 days) and be discharged after being confirmed to be malaria negative. CHMI follow-up visits at the site will take place at 3 months (D168) and 6 months (D252) post CHMI. Measurements and Procedures: Written informed consent will be taken prior to any study procedure. Healthy participants will be screened and randomised before administration of the study IMP. Vaccinations (Part 1) On the day of the 1st vaccination, the health status of the participant is re-checked and eligibility confirmed. Samples for safety, humoral, cellular and exploratory measurements are taken (baseline). Vaccination is administered and the participant remains at site for 2 hours before being discharged. Telephone follow-ups (or home visits if required) will be performed daily until 6 days after each vaccination. On 7, 14 and 28 days after each vaccination (done on D0, D28 and D56), the participant will be invited to come back to the facility and health status is checked. Further participant follow-up visits will take place at D112 (W16) and D140 (W20) post 1st vaccination. Sampling for humoral and cellular responses will be performed at D112 (W16) and D140 (W20). Additionally, sampling for exploratory measurements will be performed at D112 (W16) (Vac1 + 4 month follow-up site visit). CHMI (Part 2) 4 weeks after the 3rd vaccination, a randomly selected subset of participants (n=25; 15 SumayaVac-1 (SUM-101) & 10 Verorab® vaccinated) are invited to participate in the CHMI part of the study. On the day of the CHMI, the health status of the participant is checked and eligibility confirmed. Samples for safety, cellular, humoral and exploratory measurements are taken. CHMI is performed and the participants remain at site for 2 hours before being discharged. Telephone follow-ups (or home visits if required) will be performed daily until 4 days post CHMI to check participant's health status. 5 days post CHMI, participants will return to the site to check the health status and for admission to the ward for closer observation. During this confinement period at the site, clinical assessments and blood withdrawals will be performed until the participant is considered malaria positive (count of >500 parasites/µl in the qPCR or malaria symptoms with a positive rapid diagnostic test (RDT)) or reaches 28 days post CHMI. Blood samples will be stored for qPCR based assessment of asexual blood stage parasitemia and PMR. Once considered positive for malaria or at 28 days post CHMI (if still malaria negative), samples for exploratory measurements will be taken followed by anti-malarial treatment for 3 days. At the end of the anti-malarial treatment, the health status will be checked and blood samples will be collected to confirm asexual blood stage negativity. When there is no medical contraindication, the participant will be discharged. CHMI follow-up visits will take place at 3 months (D168) and 6 months (D252) post CHMI and will include health checks and sampling for humoral responses. Number of Participants with Rationale: Vaccination: 40 adult participants Overall: 20 SumayaVac-1 (SUM-101) and 20 Verorab® control Group 1 Sentinel sub-group 2 SumayaVac-1 (SUM-101) 1 Verorab® control Follower Group 8 SumayaVac-1 (SUM-101) 9 Verorab® control Group 2 10 SumayaVac-1 (SUM-101) 10 Verorab® control CHMI: 25 from 40 adult participants who received vaccination Overall: 15 SumayaVac-1 (SUM-101) and 10 Verorab® control Group 1 12 (7 having received SumayaVac-1 (SUM-101) & 5 having received Verorab® control) Group 2 13 (8 having received SumayaVac-1 (SUM-101) & 5 having received Verorab® control) As this is a Phase I trial, no formal sample size calculation has been done. The sample size is considered sufficient to examine the safety and reactogenicity of SumayaVac-1 (SUM-101), and humoral and cellular immunogenicity. Study Product / Intervention: Vaccination: Intra-muscular injection of SumayaVac-1 (SUM-101) composed of 150 µg MSP-1 + 5 μg GLA-SE CHMI: Direct venous inoculation of 3.2 x 103 purified, infectious P. falciparum sporozoites (PfSPZ Challenge (NF54 strain), Sanaria®) Control Intervention: Vaccination control: Intra-muscular injection of rabies vaccine (Verorab®) Study Duration: The total study duration including screening will be approximately 40 weeks including the screening period. The study duration for each participant involved in the vaccinations (Part 1) and the CHMI (Part 2) (n=25) is 36 weeks. For participants not undergoing CHMI (n=15) the study duration will be 20 weeks. Study Centre: Bagamoyo Research and Training Center of the Ifakara Health Institute Statistical Analysis incl. Power Analysis: See above for sample size justification. To evaluate the safety and reactogenicity primary endpoints, AEs and SAEs will be presented according to the endpoint definitions above. AE reporting will include verbatim term, preferred term (PT), system organ class (SOC), treatment, severity, relationship to the interventional products, and seriousness, reporting numbers of participants experiencing each event and total numbers of each event. Laboratory safety parameters will be summarized as absolute values and changes at 28 days after each vaccination compared to baseline (before 1st vaccination) and compared to values just prior to each vaccination. To evaluate the immunogenicity primary endpoints as defined above, SumayaVac-1 (SUM-101) vaccine induced humoral immunogenicity will be summarized as antibody responses to SumayaVac-1 (SUM-101) by ELISA over time, and fold changes of antibody responses relative to baseline. For all analyses, data will be listed for each participant. Descriptive analyses will be performed (number of observations, arithmetic or geometric mean, standard deviation, minimum, maximum, median, interquartile range, as appropriate, for continuous data, and counts and percentages for categorical data). Results will be presented by vaccination received, overall and separately for participants who were/were not in the CHMI part. Further details will be elaborated in a Statistical Analysis Plan (SAP), including for the secondary and exploratory objectives.

Official Title
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A Randomised, Controlled, Double-blind, Parallel Group, Single Center Phase Ib Trial to Assess Safety, Reactogenicity, Immunogenicity and Parasite Growth Rates After Controlled Human Malaria Infection of a Candidate Dual-stage Malaria Vaccine, SumayaVac-1 (MSP-1 With GLA-SE as Adjuvant) in Healthy Malaria Exposed Adults of African Origin Aged 18-45 Years

Conditions
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Malaria

Intervention / Treatment
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* Biological: SumayaVac-1(SUM-101)
* Biological: Verorab
* Biological: CHMI


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Written informed consent obtained before any study procedure. Literate participants aged 18-45 years of African origin. Female and male participants practicing contraception from 4 weeks before 1st immunization and up to 12 weeks after the last immunization or CHMI. Available to participate in follow-up for the duration of the study. Contactable by phone during the whole study period. At least two years residence in the Bagamoyo district or nearby districts in Coastal and Dar-es-Salaam regions and planning to reside there for at least 9 more months. Agreement to provide personal contact information and contact information of another household member or close friend. Female participants must be willing to avoid pregnancy if selected for participation in the trial and to undergo multiple serum pregnancy testing. Confirmation of understanding of design, procedures, risk and benefits of the study in a test with maximum of two attempts. General good health based on assessment of medical history and clinical examination. Exclusion Criteria: Previous participation in any malaria vaccine trial in the last 3 years. Participation in any other clinical trial involving investigational medicinal products within 30 days prior to the screening assessment. Previous history of drug or alcohol abuse interfering with normal social function within one year prior to enrolment. Previous vaccination with a rabies vaccine. Intake of chronic medication, especially immunosuppressive agents (steroids, immunomodulating drugs) during the 13 weeks preceding the screening visit or during the study period. Known hypersensitivity to any of the vaccine components (adjuvant or protein) or anti-malarial treatments. Body mass index (BMI) of <18 or >30 Kg/m2. Participants unable to be closely followed for social, geographic or psychological reasons. Any vaccination from 4 weeks prior to the 1st vaccination and (none planned) up to 6 weeks after the 3rd vaccination or CHMI. Symptoms, physical signs or laboratory values suggestive of systemic disorders, including renal, hepatic, cardiovascular, pulmonary, skin, immunodeficiency, psychiatric and other conditions, which could interfere with the interpretation of the trial results or compromise the health of the participants. Abnormal electrocardiogram on screening: pathologic Q wave and significant ST-T wave changes, left ventricular hypertrophy, clinically significant arrhythmias, left bundle branch block, secondary or tertiary A-V (atrio-ventricular) heart block. Any clinically significant laboratory values at screening outside of normal ranges for study participants. Malaria positivity at screening (microscopy or qPCR positive). Positive HIV, HBV or HCV tests. For females: Positive pregnancy test or actively breast feeding.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: A randomised, controlled, double-blind, parallel group, single center Phase Ib trial to assess safety, reactogenicity, immunogenicity of a candidate dual-stage malaria vaccine, SumayaVac-1 (MSP-1 with GLA-SE as adjuvant) in healthy participants aged 18-45 years. The study will also employ the Controlled Human Malaria Infection model to evaluate the ability of the vaccine candidate to induce immune responses that prevent malaria parasites from getting into the red blood cells thereby preventing development of malaria.
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: SumayaVac-1(SUM-101)<br>Candidate malaria Vaccine (Investigational Medicinal Product (IMP)). 20 participants will be randomised to receive three monthly inoculations of the IMP | Biological: SumayaVac-1(SUM-101)<br>* One immunization every 4 weeks for 3 months (total 3 immunizations)<br>Biological: CHMI<br>* Controlled Human Malaria Infection (CHMI)- challenge with Plasmodium falciparum sporozoites in a sub-group of participants who received SumayaVac-1(SUM-101) or Verorab<br>* Other names: PfSPZ;|
| Placebo Comparator: Verorab<br>Comparator used as a control. 20 participants will be randomised to receive three monthly inoculations of the comparator. | Biological: Verorab<br>* One immunization every 4 weeks for 3 months (total 3 immunizations)<br>Biological: CHMI<br>* Controlled Human Malaria Infection (CHMI)- challenge with Plasmodium falciparum sporozoites in a sub-group of participants who received SumayaVac-1(SUM-101) or Verorab<br>* Other names: PfSPZ;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Local and systemic adverse events (AEs) at least possibly related to the IMP after vaccination | Local and systemic solicited adverse events (AEs) at least possibly related to the investigational medicinal product (IMP) recorded after each vaccination (done on Day 0, Day 28 and Day 56 up to 7 days later to evaluate safety and reactogenicity of SumayaVac-1 (SUM-101) | Recorded up to 7 days after each vaccination | 
| Local and systemic unsolicited reactogenicity after vaccination | Local and systemic unsolicited reactogenicity recorded after each vaccination (done on Day 0, Day 28 and Day 56 up to 28 days later to evaluate the safety and reactogenicity of SumayaVac-1 (SUM-101) | Recorded up to 28 days after each vaccination | 
| Any serious adverse events (SAE) occurring after the 1st vaccination until the participant's last visit | Any serious adverse events (SAE) occurring after the 1st vaccination until the participant's last visit to evaluate the safety and reactogenicity of SumayaVac-1 (SUM-101) | Recorded from after 1st vaccination (Day 0 post-vaccination) until the participant's last visit (Day 252) | 
| Changes in laboratory safety parameters between baseline and 28 days after vaccination | Changes in laboratory safety parameters as defined in the protocol for every participant between baseline (Day 0 before 1st vaccination) to 28 days after each of the vaccinations to evaluate the safety and reactogenicity of SumayaVac-1 (SUM-101) | Changes recorded between baseline (Day 0 before 1st vaccination) to 28 days after each vaccination | 
| Changes in laboratory safety parameter prior to vaccination to 28 days after that vaccination | Changes in laboratory safety parameters as defined in the protocol for every participant between values recorded just prior to each vaccination (on Day 0, Day 28 and Day 56) and values found 28 days after proceeding with vaccination to evaluate the safety and reactogenicity of SumayaVac-1 (SUM-101) | Changes prior to each vaccination to 28 days after proceeding with vaccination | 
| Longevity of antibody responses to SumayaVac-1 (SUM-101) by ELISA | Longevity of antibody responses to SumayaVac-1 (SUM-101) by ELISA for all participants at Day 0 pre-vaccination, Day 28 (Week 4), Day 56 (Week 8), Day 84 (Week 12), Day 112 (Week 16), Day 140 (Week 20), and additionally at Day 168 (Week 24) and Day 252 (Week 36) for participants that undergo homologous CHMI, to evaluate the humoral immunogenicity | Titres assessed between Day 0 (pre-vaccination) up to Day 252 (last follow up visit) | 
| Fold change of antibody responses to SumayaVac-1 (SUM-101) in comparison to baseline | Fold change of antibody responses to SumayaVac-1 (SUM-101) in comparison to baseline (Day 0 pre-vaccination) for all participants to Day 28 (Week 4), Day 56 (Week 8), Day 84 (Week 12), Day 112 (Week 16), Day 140 (Week 20), and additionally at Day 168 (Week 24) and Day 252 (Week 36) for participants that undergo homologous CHMI, to evaluate the humoral immunogenicity | Fold changes assessed between Day 0 (pre-vaccination) up to Day 252 (last follow up visit) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Evaluation of the opsonic phagocytosis activity of vaccine induced antibodies | In vitro immunological assay to evaluate humoral immune responses by measuring opsonic phagocytosis activity in the sera or blood of all participants, at Day 0 pre-vaccination, Day 28 (Week 4), Day 56 (Week 8), Day 84 (Week 12), Day 112 (Week 16), Day 140 (Week 20), and additionally at Day 168 (Week 24) and Day 252 (Week 36) for participants that undergo homologous CHMI | Changes assessed between Day 0 (pre-vaccination) up to Day 252 (last follow up visit) | 
| Evaluation of complement fixation, activation and/or membrane attack complex (MAC) formation of vaccine-induced antibodies | In vitro immunological assay to evaluate humoral immune responses by assessing complement fixation, activation and/or membrane attack complex (MAC) formation in the sera or blood of all participants, at Day 0 pre-vaccination, Day 28 (Week 4), Day 56 (Week 8), Day 84 (Week 12), Day 112 (Week 16), Day 140 (Week 20), and additionally at Day 168 (Week 24) and Day 252 (Week 36) for participants that undergo homologous CHMI | Changes assessed between Day 0 (pre-vaccination) up to Day 252 (last follow up visit) | 
| Evaluation of antibody-dependent respiratory burst (ADRB) activity of vaccine-induced antibodies | In vitro lab immunological assay to evaluate immune responses by assessing antibody-dependent respiratory burst (ADRB) activity measured in the sera or blood of all participants, at Day 0 pre-vaccination, Day 28 (Week 4), Day 56 (Week 8), Day 84 (Week 12), Day 112 (Week 16), Day 140 (Week 20), and additionally at Day 168 (Week 24) and Day 252 (Week 36) for participants that undergo homologous CHMI | Changes assessed between Day 0 (pre-vaccination) up to Day 252 (last follow up visit) | 
| Evaluation of antibody-dependent cellular cytotoxicity (ADCC-NK cells) activity of vaccine-induced antibodies | In vitro immunological assay to evaluate humoral immune responses by assessing antibody-dependent cellular cytotoxicity (ADCC-NK cells) activity in the sera or blood of all participants, at Day 0 pre-vaccination, Day 28 (Week 4), Day 56 (Week 8), Day 84 (Week 12), Day 112 (Week 16), Day 140 (Week 20), and additionally at Day 168 (Week 24) and Day 252 (Week 36) for participants that undergo homologous CHMI | Changes assessed between Day 0 (pre-vaccination) up to Day 252 (last follow up visit) | 
| Evaluation of immune-mediated growth inhibition activity on Plasmodium falciparum asexual blood stage cell lines | In vitro functional assay to evaluate immune-mediated growth inhibition activity on a panel of Plasmodium falciparum asexual blood stage cell lines measured in the sera or blood of all participants, at Day 0 pre-vaccination, Day 28 (Week 4), Day 56 (Week 8), Day 84 (Week 12), Day 112 (Week 16), Day 140 (Week 20), and additionally at Day 168 (Week 24) and Day 252 (Week 36) for participants that undergo homologous CHMI | Changes assessed between Day 0 (pre-vaccination) up to Day 252 (last follow up visit) | 
| Development of P.falciparum asexual blood stage parasitemia (pre-patent period, parasite multiplication rate (PMR) and percentage of parasite negative participants in SumayaVac-1 (SUM-101) versus Verorab® arm) measured by thick blood smear (TBS) | Development of P. falciparum asexual blood stage parasitemia (pre-patent period, parasite multiplication rate (PMR) and percentage of parasite negative participants in SumayaVac-1 (SUM-101) versus Verorab® arm) measured by thick blood smear (TBS) in venous blood of all participants that undergo homologous CHMI | Changes between Day 84-Day 112 | 
| Development of P. falciparum asexual blood parasitemia (pre-patent period, PMR and percentage of parasite negative participants in SumayaVac-1 (SUM-101) versus Verorab® arm) by qPCR | Development of P. falciparum parasitemia (pre-patent period, parasite multiplication rate (PMR) and percentage of parasite negative participants in SumayaVac-1 (SUM-101) versus Verorab® arm) measured by qPCR in the venous blood for all participants that undergo homologous CHMI | Between Day 84-Day 112 | 
| Cellular immune responses to SumayaVac-1 (SUM-101) | Immune assays to assess changes in immune cell populations in response to SumayaVac-1 (SUM-101) by (i) CD4+ and CD8+ ELISpot assays, (ii) SumayaVac-1 (SUM-101) specific cells characterised by flow cytometry-based immunophenotyping using intracellular cytokine staining (ICS), (iii) functional gene expression analysis, and/or other assays to be defined measured in all participants | Changes assessed between Day 0 (pre-vaccination) up to Day 140 | 
| Comparison of MSP-1 IgG antibody concentrations by ELISA | Comparison of MSP-1 IgG antibody concentrations by ELISA between malaria pre-exposed participants in the current study and historical data obtained from malaria naïve participants of previous Phase Ia study conducted in Heidelberg that are assessed among SumayaVac-1 (SUM-101) participants only | Antibody concentrations compared between Day 0 (pre-vaccination) up to Day 84 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Plasmodium falciparum, Controlled Human Malaria Infection, Tanzania, Phase Ib, Vaccine