Pneumococcal polysaccharide conjugate antigens (multiple serotypes) conjugated to CRM197 for Asplenia

Inclusion criteria

• {"criterion_text":"- Patients with newly induced anatomical asplenia, of which the underlying cause can be: en-bloc splenectomy during pancreatic surgery because of pancreatic cancer or precancerous pancreatic lesions, or splenectomy for haematological diseases (thalassemia or sickle cell disease)\n- Patients scheduled for (en bloc) splenectomy, of which the underlying caused can be as prescribed above\n- Participants aged 18 years and older\n- Participants should have provided signed informed consent\n- Participants should be naïve for other PCVs, except for PCV20"}

Exclusion criteria

• {"criterion_text":"- Known hypersensitivity or allergy to any vaccine component\n- Pregnancy during the entire course of the study\n- Documented active haematological malignancy\n- Documented primary coagulopathy\n- Ongoing B or T cell immune deficiency such as a primary immune disorder or secondary immune disorder, such as documented HIV infection\n- Current use of any immunosuppressive drug (except NSAIDs)\n- Acute febrile illness at time inclusion\n- Receipt of PPV23 in the past year"}

Primary endpoints

• {"endpoint_text":"- Mean Fold change of PS specific IgG GMCs against PS present in PCV20 and PCV21 (common serotypes) 2-3 weeks after booster vaccination with PCV21, at least 12 months after primary vaccination with PCV20 in asplenic patients primed before or after splenectomy.","definition_or_measurement_approach":"Measured as mean fold change of pneumococcal serotype (PS)-specific IgG geometric mean concentrations (GMCs) 2-3 weeks after PCV21 booster vaccination, at least 12 months after primary PCV20 vaccination, for serotypes present in both vaccines."}

Secondary endpoints

• {"endpoint_text":"- Difference in height of PS-specific IgG GMCs and PS-specific IgG B cell response, % of participants with a >2 and >4 fold change 3 weeks after primary and 2-3 weeks after booster, compared to primary vaccination before and after splenectomy and with healthy controls, for PS present in both vaccines (common serotypes) and unique for PCV21","definition_or_measurement_approach":"Measured as PS-specific IgG GMCs and PS-specific IgG memory B cell responses; report % participants with >2-fold and >4-fold rises at 3 weeks after primary and 2-3 weeks after booster; comparisons between vaccination before vs after splenectomy and with healthy controls, for shared and PCV21-unique serotypes."}
• {"endpoint_text":"- PS-specific IgM GMC persistence at 12 after primary and 6-12 months after booster, for PS present in both vaccines (common serotypes) and unique for PCV21","definition_or_measurement_approach":"Measurement of PS-specific IgM geometric mean concentrations (GMCs) at 12 months after primary vaccination and at 6-12 months after booster vaccination for shared and PCV21-unique serotypes."}
• {"endpoint_text":"- Correlation between IgG GMC height and PS-specific IgG memory B cell count 3 weeks after primary and 2-3 weeks after booster, for PS present in both vaccines (common serotypes) and unique for PCV21","definition_or_measurement_approach":"Correlation analysis between PS-specific IgG GMC magnitude and PS-specific IgG memory B cell counts at 3 weeks post-primary and 2-3 weeks post-booster for shared and PCV21-unique serotypes."}
• {"endpoint_text":"- Mean fold change of PS specific IgG GMCs 2-3 weeks after PCV21 vaccination, for PS unique in PCV21.","definition_or_measurement_approach":"Measured mean fold change of PS-specific IgG GMCs 2-3 weeks after PCV21 vaccination for serotypes unique to PCV21."}

Netherlands

Earliest CTIS Part Ii Submission Date

31-07-2025

Latest Decision Or Authorization Date

11-08-2025

Processing Time Days

11

Number Of Sites

1

Number Of Participants

70

Primary sponsor

Full Name

Leids Universitair Medisch Centrum (LUMC)

Organisation Type

Hospital/Clinic/Other health care facility

Country Of Registered Address

Netherlands