Schistosoma Mansoni, Schistosomiasis
Conditions
Brief summary
The goal of this clinical trial is to learn about the Sm-p80 + GLA-SE (Schistoshield®) vaccine in healthy participants who have not had schistosomiasis before. The main questions it aims to answer are: * if the vaccine is safe * if after vaccinated people start producing antibodies * if the vaccine works against schistosomiasis. Participants will receive three vaccines (or placebo) and are then exposed to 20 male Schistosoma cercariae. Afterwards they are treated with praziquantel to cure the infection. Researchers will compare the group vaccinated with Schistoshield® and placebo (fake vaccination) to see if the vaccine has worked.
Interventions
BIOLOGICALSm-p80 + GLA-SE Vaccine
30 μg Sm-p80 + 5 μg GLA-SE
OTHERPlacebo
0.9% Sterile Normal Saline
BIOLOGICALSchistosoma mansoni infection
20 viable male Schistosoma mansoni cercariae of the Puerto Rican strain
Sponsors
Texas Tech University Health Sciences Center
MRC/UVRI and LSHTM Uganda Research Unit
Leiden University Medical Center
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
Inclusion criteria
1. Subject is aged ≥ 18 and ≤ 45 years and in good health. 2. Subject has adequate understanding of the procedures of the study and agrees to abide strictly thereby. 3. Subject is able to communicate well with the investigator, is available to attend all study visits. 4. Subject will not travel to Schistosoma-endemic countries up until treatment at week 24. 5. Subject agrees to refrain from blood and plasma donation to Sanquin or for other purposes throughout the study period. 6. For female subjects: subject agrees to use adequate contraception and not to breastfeed for the duration of study. 7. Subject has signed informed consent.
Exclusion criteria
1. Any history, or evidence at screening, of clinically significant symptoms, physical signs or abnormal laboratory values suggestive of systemic conditions, such as cardiovascular, pulmonary, renal, hepatic, neurological, dermatological, endocrine, malignant, haematological, infectious, immune-deficient, (severe) psychiatric and other disorders, which could compromise the health of the participant during the study or interfere with the interpretation of the study results. These include, but are not limited to, any of the following: * body weight \<50 kg or Body Mass Index (BMI) \<18.0 or \>35.0 kg/m2 at screening; * positive HIV, HBV or HCV screening tests; * the use of immune modifying drugs within three months prior to study onset (inhaled and topical corticosteroids and oral anti-histamines exempted) or expected use of such during the study period; * history of malignancy of any organ system (other than localized basal cell carcinoma of the skin), treated or untreated, within the past 5 years; * any history of treatment for severe psychiatric disease by a psychiatrist in the past year; * history of drug or alcohol abuse interfering with normal social function in the period of one year prior to study onset. 2. The chronic use of any drug known to interact with praziquantel, artesunate or lumefantrine metabolism (e.g. phenytoïn, carbamazepine, phenobarbital, primidon, dexamethason, rifampicine, cimetidine, flecaïnide, metoprolol, imipramine, amitriptyline, clomipramine, class IA and III anti-arrythmics, antipsychotics, antidepressants, macrolides, fluorchinolones, imidazole- and triazole antimycotics, antihistamines). Because lumefantrine may cause extension of QT-time, chronic use of drugs with effect on QT interval will result in exclusion from study participation. 3. Any planned vaccination within 28 days before the start of the trial until the end of the immunisation phase (week 12), with the exception of SARS-CoV-2 vaccines or influenza vaccines. 4. For female subjects: positive serum pregnancy test on the day before first immunisation. 5. Any history of schistosomiasis or treatment for schistosomiasis. 6. Positive serology for schistosomiasis or elevated serum CAA at screening. 7. Known hypersensitivity to or contra-indications (including co-medication) for use of praziquantel, artesunate or lumefantrine. 8. Being an employee or student of the department of Parasitology or Infectious diseases of the LUMC.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Vaccine efficacy | week 12-24, i.e. after challenge | The protective efficacy of Sm-p80 + GLA-SE to male Sm cercariae measured by the difference in frequency of serum CAA positivity (≥1.0 pg/mL) between the vaccine group and placebo |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Safety of (repeated) immunisation | week 0-12 | Frequency and severity of adverse events after (repeated) immunisation with Sm-p80 + GLA-SE |
| Immunogenicity | week 0-24 | Anti-Sm-p80 IgG antibody titres after (repeated) immunisation with Sm-p80 + GLA-SE measured by ELISA |
Other
| Measure | Time frame | Description |
|---|---|---|
| Antibody responses | week 0-24 | Comparison of (glycan) antibody responses directed against Sm antigens between the vaccine and placebo participants as well as between protected and non-protected participants after exposure to male Sm cercariae at week 12 using protein and glycan arrays |
| Cellular responses | week 0-24 | Comparison of cellular responses directed against Sm antigens between the vaccine and placebo groups after immunisation and after controlled human infection with Sm cercariae, as well as between protected and non-protected participants |
| Time to CAA positivity | week 12-24 | Comparison of time to positive serum CAA test between the vaccine and placebo groups after exposure to male Sm cercariae at week 12 |
| Transcriptomic profile | week 0-24 | Identification, characterization and comparison of gene expression changes as measured using RNA-seq analysis from PBMC between placebo and vaccine groups |
| In vitro killing | week 0-24 | Enumeration of the ability of Sm-p80-specific antibodies from human subjects to kill schistosome larvae in vitro from sera collected prior to each vaccination |
| Peak CAA levels | week 12-24 | Comparison of peak serum CAA concentrations between the vaccine and placebo groups after exposure to male Sm cercariae at week 12 |
| Eosinophils | week 12-24 | Comparison of peak eosinophil counts between the vaccine and placebo groups after exposure to male Sm cercariae at week 12 |
Contacts
Primary ContactMeta Roestenberg, Prof
Outcome results
None listed