Prospective Study on the Vaccine Response to Meningococcal B Vaccine After Allogeneic Stem Cell Transplantation

Study Overview
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Brief Summary
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Allogeneic hematopoietic stem cell transplant (HSCT) recipients are at risk of various bacterial infections, especially due to a progressive decrease of specific antibodies. Around 90% of HSCT recipients have unprotective titers of specific antibodies to serogroups A and C meningogocci (Parkkali 2001; Mahler 2012). Some small studies suggest that the response to meningococcal A and C vaccines is close to 100% after 3 doses given 18 months after transplant. Although the response to 2 doses of 4CMenB is over 75% in other immunocompromised patients (Feavers, 2017), studies with 4CMenB are lacking after HSCT. Nevertheless, as serogroup B caused 74% of IMD in Europe between 2004-2014 (Whittaker, 2017), the meningococcal B vaccination is recommended by the more recent guidelines from 6 months after transplant. There are, however, no data on the safety and efficacy of this vaccine after hematopoietic stem cell allograft (HSCT). The objective of this study is to assess the response to 2 doses of a multicomponent meningococcal B vaccine (4CMenB) given at 2 months interval in adult allogeneic HSCT recipients transplanted at least 6 months ago. The response will be assessed 1 month and 10 months after the second dose of vaccine by measuring bactericidal antibodies against NadA, fHbp, NHBA and PorAP1 vaccinal antigens according to methods previously reported (Caron Lancet Infect Dis 2011). The response rate will be correlated to pre- and post-transplant factors. The hypothesis of this study is that 80% of the patients should have protective titers one month after the 2nd dose.

Detailed Description
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Monocentric study. Forty patients are expected. Primary objective: Response rate one month after 2 doses of vaccine Secondary objectives: safety, rate of protection before vaccination, comparison of the antibody titers at one month vs. at 10 months after the vaccine program. Relationship between pre and post-transplant factors.

Official Title
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Prospective Study on the Vaccine Response to Meningococcal B Vaccine After Allogeneic Stem Cell Transplantation

Conditions
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Hematopoietic Stem Cell Transplant, Meningococcal Vaccine

Intervention / Treatment
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* Biological: B vaccination


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Allogeneic HSCT at least 6 months before Age ≥ 18 years Platelet count > 50 G/L Exclusion Criteria: Rituximab administration in the previous 6 months Relapse of the underlying disease

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: B vaccination<br>One intramuscular injection of Bexsero (multicomponent B vaccine) from 6 months after transplant. A second similar dose will be given 2 months later. | Biological: B vaccination<br>* One intramuscular injection of Bexsero (multicomponent B vaccine) from 6 months after transplant. A second similar dose will be given 2 months later.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| % of patients with Bactericidal titers > 4 to at least one component of the Bexsero vaccine, 1 month after the 2nd dose. | Vaccine response rate at one month after the 2nd dose. | 1 month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| % of patients with Bactericidal titers > 4 to at least one component of the Bexsero vaccine, 12 months after the 1st dose. | Vaccine response rate at 12 month after the 1st dose. | 12 month | 
| Number of adverse events of vaccination by Bexsero after Allograft of CSH. | Number of adverse events (non serious and serious) reported during the study | 12 month | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Allogeneic stem cell transplantation