B Cell Response to a Primary and a Booster Course of the Novartis Meningococcal ACWY Conjugate Vaccine in Healthy Infants

The memory B cell response at one month after primary vaccinations (5 months of age) was defined as the mean number of meningococcal serogroup A, C, W-135 and Y specific memory B cells, measured in vitro by ELISpot assay per 2x100000 lymphocytes obtained from culture (LOC) of peripheral blood mononuclear cells (PBMC) circulating in blood incubated for 5.5 days in the presence of polyclonal B cell activators. Serogroup A, C, W-135 and Y geometric mean titers (GMTs) were measured by serum bactericidal assay using human complement (hSBA) at 12 months of age (before third dose). Correlation and linear regression coefficients were determined between memory B cells at 1 month after primary vaccinations with MenACWY-CRM (5 months of age) and hSBA titers at 12 months of age (before third dose) for the serogroups A, C, W-135 and Y.

Time frame: 1 month after primary vaccination and immediately before third dose at 12 months of age

Population: Analysis was performed on per-protocol (PP) dataset of primary vaccination, i.e. subjects who received all the relevant doses of vaccine correctly; provided evaluable blood samples at the relevant time points; and had no major protocol violation as defined prior to analysis.

The serogroup A, C, W-135 and Y specific IgG concentrations were measured in the serum of mothers at the time of their enrollment into the study (Day 1) by ELISA.

Time frame: Day 1 (IgG) and one month after primary vaccination (B cells)

Population: Analysis was performed on the PP primary population.

CRM197 specific memory B cell response at each time point was measured as mean number of CRM197 specific memory B cells by ELISpot assay per 2x100000 LOC. CRM197 specific IgG concentration was measured by ELISA at 12 months of age and one month after MenACWY-CRM booster vaccination.

Time frame: 5 months (B cells), 12 months and 13 months (B cells and IgG) of age

Population: Analysis was done on the PP primary population and PP booster population.

hSBA GMTs were measured before and one month after MenACWY-CRM booster vaccination at 12 months of age.

Time frame: Before and one month after booster vaccination

Population: Analysis was performed on the PP dataset of booster vaccination.

Serogroup A, C, W-135 and Y specific IgG concentrations were measured before and one month after MenACWY-CRM booster vaccination by ELISA.

Time frame: Before and one month after booster vaccination

Population: Analysis was performed on the PP dataset of booster vaccination.

Memory B cell response before and one month after MenACWY-CRM booster vaccination at 12 months of age was measured as mean number of meningococcal serogroup A, C, W-135 and Y specific memory B cells by ELISpot assay per 2x100000 LOC.

Time frame: Before and one month after booster vaccination

Population: Analysis was performed on the PP dataset of booster vaccination.

Linear regression analysis between memory B cells at 5 months of age and hSBA titers and IgG at 12 months of age was performed with and without inclusion of demographic factors (subject's household smoking status, number of older children living in subject's household, attendance at daycare and total duration of breast feeding) in the model.

Time frame: 1 month post primary vaccination (B cells) and 12 months (hSBA titers and IgG)

Population: Analysis was performed on the PP dataset of persistence population.

The rise in serogroup-specific hSBA and IgG was calculated by pre/post third dose geometric mean ratios, calculated by the difference in the log10 of the concentrations/titers measured at 13 months to the log10 of the concentrations at 12 months: i.e. rise = log10(x) at 13 months minus log10(x) at 12 months where x is the serogroup specific IgG or SBA titers. Linear regression analysis between memory B cells at 5 months of age and rise in hSBA titers or IgG at 12 months of age was performed with and without inclusion of demographic factors (subject's household smoking status, number of older children living in subject's household, attendance at daycare and total duration of breast feeding) in the model.

Time frame: 1 month post primary vaccination (B cells) and 12 months (hSBA titers and IgG)

Population: Analysis was performed on the PP dataset after booster vaccination.

Memory B cell response at 1 month after primary vaccination and at 1 week after third vaccination was measured as mean number of meningococcal serogroup specific memory B cells by ELISpot assay per 2x100000 LOC. Plasma B cell response at 1 week after vaccination was measured as the mean number of cells secreting antibodies specific for meningococcal serogroup A, C, W-135 and Y, measured by ELISpot assay, per 2x100000 PBMC. Serogroup A, C, W-135 and Y specific IgG were measured by ELISA and hSBA GMTs were measured at 1 week after third vaccination.

Time frame: One month after primary vaccination and 1 week after third vaccination

Population: This outcome was assessed in Group 3 subjects only as they provided a blood draw at 1 week following the MenACWY-CRM booster vaccination. Analysis was performed on PP booster population.

Memory B cell response at 1 month after MenACWY-CRM primary and third (booster) vaccination was measured as mean number of meningococcal serogroup specific memory B cells by ELISpot assay per 2x100000 LOC. The serogroup A, C, W-135 and Y specific IgG concentrations at 1 month after MenACWY-CRM booster were measured by ELISA. hSBA GMTs were measured by hSBA assay one month after MenACWY-CRM booster vaccination. The rise in serogroup specific IgG, memory B cells and hSBA was calculated by pre/post third dose geometric mean ratios, calculated by the difference in the log10 of the concentrations/titers measured at 13 months to the log10 of the concentrations at 12 months: i.e. rise = log10(x) at 13 months minus log10(x)at 12 months where x is the serogroup specific IgG or memory B cell concentrations or SBA titers.

Time frame: 1 month after primary and pre-third and 1 month after third vaccination

Population: Values from Group 1 were analyzed separately. Values from Groups 2 and 3 were combined for the analysis. Groups 2 and 3 received PCV at 12 months while Group 1 received PCV at 13 months.~Analysis was performed on PP booster population.

Memory B cell response at 1 month after primary vaccination and immediately before third dose at 12 months of age was measured as mean number of meningococcal serogroup specific memory B cells by ELISpot assay per 2x100000 LOC. The meningococcal serogroup A, C, W-135 and Y specific IgG concentrations immediately before third dose at 12 months of age were measured by ELISA.

Time frame: 1 month after primary vaccination and immediately before third dose

Population: Analysis was performed on PP dataset of persistence population.

Memory B cell response at 1 month after MenACWY-CRM primary and booster vaccinations was measured as mean number of meningococcal serogroup specific memory B cells by ELISpot assay per 2x100000 LOC. hSBA GMTs for the serogroup A, C, W-135 and Y were measured one month after the third MenACWY-CRM vaccination. The meningococcal serogroup A, C, W-135 and Y specific IgG concentrations one month after third MenACWY-CRM vaccination were measured by ELISA.

Time frame: 1 month after primary vaccination and 1 month after third vaccination

Population: Values from Group 1 were analyzed separately. Values from Groups 2 and 3 were combined for the analysis. Groups 2 and 3 received PCV at 12 months while Group 1 received PCV at 13 months.~Analysis was performed on PP booster population.

Safety was assessed as the percentage of subjects who reported injection site local reactions during 7-day follow-up period after each MenACWY-CRM and routine infant vaccination administered as a primary course of vaccination.

Time frame: 7 days post each MenACWY-CRM and routine infant vaccination

Population: The analysis was performed on the Safety Population.

Safety was assessed as the percentage of subjects who reported injection site local reactions during 7-day follow-up period after MenACWY-CRM and PCV vaccinations at 12 months of age.

Time frame: 7 days post 12 month vaccination

Population: The analysis was performed on safety after booster population (safety population who received vaccination at 12 months of age).

Safety was assessed as the percentage of subjects who reported systemic reactions during 7-day follow-up period after MenACWY-CRM and PCV vaccination at 12 months of age.

Time frame: 7 days post 12 months vaccination

Population: The analysis was performed on safety after booster population (safety population who received vaccination at 12 months of age).

Safety was assessed as the percentage of subjects who reported systemic reactions during 7-day follow-up period after MenACWY-CRM (2 and 4 months) and routine infant primary vaccinations (2, 3 and 4 months).

Time frame: 7 days post vaccination at 2, 3, and 4 months of age

Population: The analysis was performed on the safety population.

To assess the kinetics of serogroup A, C, W-135 and Y specific hSBA titers, the geometric mean titer was measured on day 0, 7, 14, 30, 49, 90, and 120 following vaccination with MenACWY-CRM vaccination at month 4 of the study.

Time frame: Day 0, 7, 14, 30, 49, 90,120 after MenACWY-CRM vaccination at month 4

Population: This outcome was assessed in Group 1 PP set population.

To assess the kinetics of serogroup A, C, W-135 and Y specific IgG concentrations, the geometric mean concentration was measured on day 0, 7, 14, 30, 49, 90, and 120 following vaccination with MenACWY-CRM vaccination at month 4 of the study.

Time frame: Day 0, 7, 14, 30, 49, 90,120 after MenACWY-CRM vaccination at month 4

Population: This outcome was assessed in Group 1 PP set population.

To assess the kinetics of serogroup A, C, W-135 and Y specific memory B cells, plasma B cells and IgG concentrations were measured on days 0, 7, 14, 49, 90, and 120 following vaccination with MenACWY-CRM vaccination at month 4 of the study. The memory B cell response at different timepoint was defined as the mean number of meningococcal serogroup A, C, W-135 and Y specific memory B cells, measured in vitro by ELISpot assay per 2x100000 lymphocytes obtained from culture (LOC) of peripheral blood mononuclear cells (PBMC) circulating in blood incubated for 5.5 days in the presence of polyclonal B cell activators in vitro. The B plasma cell response at each time point was defined as the mean number of cells secreting antibodies specific for meningococcal serogroup A, C, W-135 and Y, measured by ELISpot assay, per 2x100000 PBMC.

Time frame: Day 0, 7, 14, 49, 90, and 120 after MenACWY-CRM vaccination at month 4

Population: This outcome was assessed in Group 1 PP set population.

The memory B cell response in children lacking a hSBA titer ≥1:8 one month after MenACWY-CRM primary vaccination was calculated as the mean number of meningococcal serogroup specific memory B cells, measured by ELISpot assay per 2x100000 LOC.

Time frame: One month after primary vaccination

Population: Analysis was performed on the PP primary population and PP persistence population, subjects lacking hSBA ≥1:8 one month after primary vaccination.