Searching Patterns In the Robustness of Immunological FVIII Tolerance
Trial statusNot yet recruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
AgeUp to 18
SponsorAcademisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)
About this trial
Children with hemophilia A lack clotting factor VIII (FVIII) due to a genetic mutation. It is well known that administration of FVIII concentrate leads to immunological tolerance for the FVIII protein in the majority of children. In 30% of these children tolerance is not achieved leading to the development of anti-FVIII antibodies (i.e. inhibitors). Our knowledge on the underlying immunological mechanisms leading to tolerance is limited. Recently, Non-Factor Therapy (NFT) has become available for prevention of bleeding in patients with hemophilia, i.e. prophylaxis. Currently, many children with severe hemophilia A use NFT as the subcutaneous administration of NFT is very convenient. In children on NFT prophylaxis, intravenous FVIII concentrate is exclusively used on-demand for treatment of bleeding. As NFT is very effective in the prevention of bleeds, patients may not be exposed to the deficient FVIII protein for periods up to a year or longer. It is currently not known how robust immunological tolerance is in the absence of exposure to a deficient antigen. The infrequent exposure to FVIII, enabled by NFT, provides an opportunity to study the immunological tolerance mechanisms for FVIII in children with hemophilia A.
The aim of SPIRIT is to investigate the mechanisms of the immunological tolerance to FVIII in patients with hemophilia A aged younger than 18 years using NFT for prophylaxis.
In this observational cohort study, children (aged \<18 years) with congenital hemophilia A, who are treated with non-factor therapy as prophylaxis, will be longitudinally followed. Participants will have blood drawn anually, during the regular clinic visits, and additionally following FVIII exposure. Feces samples will be collected and analyzed in children aged \<12 years, following the same scheme as blood sampling.
The main study endpoint are the immunological mechanisms underlying tolerance to FVIII, including presence, titers, subtypes and affinities of FVIII-specific (non-)neutralizing antibodies, FVIII-specific T and B cell responses and the role of gut microbiota.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Congenital hemophilia A of all severities
Using NFT for prophylaxis
Aged under 18 years
Written informed consent
Disqualifiers
Acquired hemophilia A
Any other bleeding disorder
Trial population
Children with hemophilia A, who are treated with non-factor therapy as prophylaxis, and who are aged \<18 years. The subjects will be recruited from Hemophilia Treatment Centres (HTCs) in the Netherlanss and internationally.
Trial design
Design model
Cohort
Time perspective
Prospective
Treatments tested in this trial
Not listed
Trial groups
500 Participants
are grouped into 1 trial groupGroup A: Children with congenital Hemophilia A on NFT
Trial outcomes
Primary outcomes
1
FVIII-specific non-neutralizing antibody development
Patients will be longitudinally monitored for the development of FVIII-specific non-neutralizing antibodies (NNAs). The development of FVIII-specific NNAs will be assessed with a direct enzyme-linked immunosorbent assay (ELISA)(Optical Density (OD)), by reporting the presence of FVIII-specific NNAs (Yes/No). Incidence will be calculated as the proportion of patients who develop newly detectable FVIII-specific NNAs during the study period.
Time frame
From enrollment up to 5 years2
Characterization of FVIII-specific antibodies (Immunoglobulin isotypes)
FVIII-specific antibodies will be characterized by measuring immunoglobulin isotypes (IgA, IgM, and IgG) over time using ELISA.
Time frame
From enrollment up to 5 years3
Characterization of FVIII-specific antibodies (IgG subclasses)
FVIII-specific antibodies will be characterized by measuring IgG subclasses (IgG1, IgG2, IgG3, and IgG4) over time using ELISA.
Time frame
From enrollment up to 5 years4
Characterization of FVIII-specific antibodies (affinity)
FVIII-specific antibodies will be characterized by measuring the affinity (KA \[M-1\]) over time using ELISA.
Time frame
From enrollment up to 5 yearsSecondary outcomes
1
FVIII-specific T and B cell responses
FVIII-specific T- and B-cell responses will be characterized by assessing differential gene expression profiles and immune activation signatures over time using RNA sequencing. FVIII-specific T- and B-cell responses will be compared between patients with FVIII-specific NNAs and/or inhibitors and patients without FVIII-specific NNAs and/or inhibitors.
Time frame
From enrollment up to 5 years2
Immunomodulatory microbial metabolites (in children <12 years)
In participants younger than 12 years of age, concentrations of immunomodulatory microbial metabolites (i.e. short chain fatty acids, including butyrate and/or tryptophan catabolites (umol/g)) in fecal samples will be assessed over time using high-performance liquid chromatography with ultraviolet detection (HPLC-UV). Concentrations of immunomodulatory microbial metabolites in fecal samples will be compared between patients with FVIII-specific NNAs and/or inhibitors and patients without FVIII-specific NNAs and/or inhibitors.
Time frame
From enrollment up to 5 years3
Gut microbiota composition (in children <12 years)
In participants younger than 12 years of age, microbial composition, including diversity indices and diversity indices, in fecal samples will be assessed over time using 16S rRNA gene sequencing. Gut microbiota composition in fecal samples will be compared between patients with FVIII-specific NNAs and/or inhibitors and patients without FVIII-specific NNAs and/or inhibitors.
Time frame
From enrollment up to 5 yearsSponsors and contacts
Click on the lead sponsor to view all of their trials.
Academisch Medisch Centrum - Universiteit van Amsterdam (AMC-UvA)
Lead sponsor
Amsterdam UMC, location AMC
Sponsor institution
Amsterdam UMC, location AMC
Collaborator
Source ClinicalTrials.gov
This trial is not recruiting at the moment. You can still explore other options: