Safety and Immunogenicity Study of Plasmodium Vivax CS Derived Synthetic Peptides Formulated in Two Adjuvants

Study Overview
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Brief Summary
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This was a phase I double blind controlled vaccine trial, evaluating safety, tolerability and immunogenicity of mixtures of N, R and C LSP derived from the P. vivax CS protein formulated in two adjuvants Montanide ISA 720 and Montanide ISA 51. The primary objective was to assess in malaria-naïve adults, the safety and reactogenicity of these peptides formulated in the two adjuvants We recruited 40 healthy men and women volunteers from Cali, Colombia, a city non-endemic for malaria. Volunteers were 19--41 years of age and had no history of malaria. During a period of three months a total of 100 volunteers were assessed for eligibility criteria in order to select a total of 40 volunteers willing to participate in the clinical trial. By consecutive allocation, eight participants were allocated to each of the five experimental groups (A--E): four groups (A--D) were immunized with the vaccine formulations at two different dose concentrations and formulated in two different adjuvants. A control group (E) was injected with placebo (saline solution)

Detailed Description
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The study corresponds to a clinical trial, randomized double-blind, controlled, dose escalation, Phase IB, which will assess the safety and immunogenicity of a mixture of synthetic peptides derived from CS protein of P. vivax, formulated in adjuvant Montanide ISA 720 and 51; in healthy men and nonpregnant women without previous history of malaria infection. In order to optimize the vaccine dose, eligible participants were enrolled to receive three doses of vaccine containing peptide mixtures at a dose of 50 ug or 100 ug of each individual peptide, for a final dose of 150 ug or 300 ug respectively, in a volume of 0.5 mL. The previous clinical trial had indicated that doses between 30 ug and 100 ug produced better responses than lower doses. The first immunization dose (given at Month 0) contained the peptides N and C only, whereas the two boosting doses (given at Months 2 and 4) contained all three (N, R, and C) peptides (Table 1). Vaccination was performed by intramuscular injection in the deltoid muscle, alternating arms with each injection. For safety reasons, participants assigned to the low vaccine dose groups were immunized first and only two weeks after initiation when no serious adverse events (SAE) had occurred, immunization of participants in the high-dose was started. Half of the participants assigned to receive placebo were immunized along with each dose level group. Clinical monitors and the IRBs of the University of Valle and IMC, evaluated the occurrence and severity of adverse events (AE) associated with immunization. The occurrence of more than three AE (severity grade 2 or higher) or one SAE related to the vaccine would have led to study termination. Participants who left the study were not replaced.

Official Title
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Malaria Vaccine Phase IB Clinical Trial: Safety and Immunogenicity Study of Plasmodium Vivax CS Derived Synthetic Peptides Formulated in Two Adjuvants

Conditions
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Malaria, Vivax

Intervention / Treatment
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* Drug: Peptides (N,R&C) formulated in Montanide ISA 720
* Drug: Peptides (N,R&C) formulated in Montanide ISA 51
* Drug: Peptides (N,R&C) formulated in Montanide ISA 720
* Drug: Peptides (N,R&C) formulated in Montanide ISA 51
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy adults (male and non-pregnant female) 18- 45 years old, without previously malaria infection (naïve volunteers), capable to pass a comprehension test on the study and able to provide written informed consent to participate in the trial. Use of adequate contraceptive method since the initiation of the study and until two months after the end of the study. No plans to travel to a malaria endemic area during the course of the study. Reachable by phone during the study period (1 year). No use of other vaccines since 3 months before the beginning of the study and during it. Exclusion Criteria: Females who intend to become pregnant within the 3 months following the screening visit or who are pregnant at screening time, ascertained by urine or serum pregnancy test (B-HCG). Women who are breast-feeding will also be excluded. Reason for exclusion: The immunological changes accompanying pregnancy and lactation could alter the results of the assays performed. If a pathological condition appear, it could be carried to the vaccine. Duffy negative phenotype. Justification: Individuals with this phenotype are refractory to P. vivax infection. G-6-PD deficiency or any genetic defect (hemoglobinopathy). Justification: These conditions influence the development of P. vivax infection. History of previous experimental malaria vaccination. Justification: Individuals who have been previously immunized may show a response due to the past immunization and not to the present one. Clinical or laboratory evidence of significant systemic disease, including hepatic, renal, cardiac, immunologic or hematological disease. Justification: The results of the study could have a negative impact on the study if volunteers are suffering from any of these diseases. Evidence of active hepatitis B or C or HIV infection. Justification: Serious underlying medical condition could affect the immunological responses of volunteers or could increase the risk or severity of adverse events associated with participation in this study. Clinically significant laboratory abnormalities as determined by the investigator(s). Justification: Baseline abnormal laboratory values may indicate a serious underlying medical condition and also will make it difficult to evaluate AE´s during the conduct of the study. • Known history of autoimmune (including inflammatory bowel disease, rheumatoid arthritis, lupus) or connective tissue disease. Justification: Autoimmune diseases could affect the immunological responses of volunteers and could increase the risk to the volunteer. • Individuals receiving treatment with steroids or non-steroidal anti-inflammatory drugs or any immunosuppressive therapy. Justification: These drugs could affect the immunological responses of volunteers and could increase the risk to the volunteer. Known history of drug or alcohol abuse interfering with normal social function. Justification: Pharmaco-dependency alters the capacity of free decision and produce physical or psychiatric undesirable condition that could affect the study. Volunteers unable to give written informed consent or with difficulties to understand the study. Justification: Volunteers must have the capacity to provide informed consent in order to participate in any research involving humans

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

Allocation: Randomized
Intervention Model: Factorial Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Group A<br>Montanide ISA 720 Dose by peptide 50ug | Drug: Peptides (N,R&C) formulated in Montanide ISA 720<br>* 50 ug<br>* Other names: Peptides (N, R & C) from P. vivax CS protein;|
| Active Comparator: Group B<br>Montanide ISA 51 Dose by peptide 50ug | Drug: Peptides (N,R&C) formulated in Montanide ISA 51<br>* 50 ug<br>* Other names: Peptides (N, R & C) from P. vivax CS protein.;|
| Active Comparator: Group C<br>Montanide ISA 720 Dose by peptide 100ug | Drug: Peptides (N,R&C) formulated in Montanide ISA 720<br>* 100 ug<br>* Other names: Peptides (N, R & C) from P. vivax CS protein.;|
| Active Comparator: Group D<br>Montanide ISA 51 Dose by peptide 100ug | Drug: Peptides (N,R&C) formulated in Montanide ISA 51<br>* 100 ug<br>* Other names: Peptides (N, R & C) from P. vivax CS protein;|
| Placebo Comparator: Group E<br>Control Group. no peptide. Isotonic saline solution | Other: Placebo<br>* PLacebo: Isotonic saline solution<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Safety and Immunogenicity of Plasmodium vivax CS Derived Long Synthetic Peptides Adjuvanted with Montanide ISA 720 or Montanide ISA 51 |  | 9 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Immunogenicity assessment | Specific anti CS antibodies determination (B cell response) and specific induction of IFNγ production (T cell response). All sera samples will be kept at -70° in Immunology Institute, FCVL or Asoclinic until use. | 9 month | 
| Adverse Events | Each AE will be written on CRF forms and will be immediately be informed to the clinical monitor and IRB. All volunteers will be followed until recovering it the initial condition. Additional physical examination and laboratory tests will be performed in case any relation between the AE and the immunogen needs to be established. | 9 month | 
| Safety Laboratories | Complete blood cell count, hepatic and renal function tests will be made on months 1, 2, 3, 6, 7 y 9 after the first immunization. Every change in the laboratory results will be reported on the corresponding CRF´s; severity associated with vaccination will be established. Specific studies will be made if it is necessary the AE end will be determined when these parameters will be normal. | 8 month | 
| B-cell response | Specific antibody titers will be measured by ELISA technique using the corresponding peptide (N, R, C) as coating antigen and the recognition of the native protein will be assessed by Immunofluorescence technique (IFAT) using P vivax sporozoites obtained by dissection of experimentally infected Anopheles mosquitoes [91] Antibody titers will be considered as positive at 1:100 dilution by ELISA and 1:40 by IFAT. | 8 month | 
| T-cell response evaluation | Cell mediated immune (CMI) responses will be evaluated will be made by the cytokines IFN-γ production using peripheral blood mononuclear cells (PBMC) using both ELIspot and ELISA techniques. | 8 month | 
| Cytokine Production Evaluation by ELISA | PBMC will be stimulated with each of the three peptides (N, R or C) in a concentration of 10ug/ml and cells cultures without the peptide will be used as negative control. PBMC stimulated with phyto-hemaglutinin (PHA) will be used as positive controls. | 8 month | 
| Cytokine Production by ELIspot | This evaluation will be made in two phases: First the cytokine production in total PBMC, which will be stimulated with CS protein derived peptides of different length. Second, positive samples for cytokine will be used to evaluate the production of cytokines by purified T lymphocytes subpopulations CD4+ or CD8+. This will determine the subpopulation responsible for cytokine production. A positive selection of cell subpopulations will be performed using anti-CD4+ / CD8+ coated pearls using MACS, and will be further used for ELIspot. | 8 month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Malaria, Synthetic peptides, Plasmodium vivax, Human volunteers