Clinical Pharmacology for Capvaxive
Mechanism Of Action
Protection against invasive pneumococcal disease is conferred mainly by opsonophagocytic killing of S. pneumoniae. CAPVAXIVE induces OPA against 22 S. pneumoniae serotypes. The de-O-acetylated polysaccharide from serotype 15B has a molecular structure similar to the polysaccharide from serotype 15C and induces OPA to serotype 15C. The deOAc15B also induces cross-reactive OPA against serotype 15B. An OPA titer that is predictive of protection against invasive pneumococcal disease or pneumococcal pneumonia has not been established.
Clinical Studies
For studies 1-4, immunogenicity was assessed by serotype-specific opsonophagocytic activity (OPA) responses at 1-month postvaccination. The primary immunogenicity endpoints included OPA geometric mean titers (GMTs) and the proportion of individuals who achieved ≥4-fold rise in OPA responses from prevaccination to 1-month postvaccination.
Individuals 18 Years Of Age And Older
The effectiveness of CAPVAXIVE in individuals 18 years of age and older for the prevention of invasive disease caused by S. pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15B, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F and 35B and for the prevention of pneumonia caused by S. pneumoniae serotypes 3, 6A, 7F, 8, 9N, 10A, 11A, 12F, 15A, 15C, 16F, 17F, 19A, 20A, 22F, 23A, 23B, 24F, 31, 33F, and 35B was demonstrated based on comparative immunogenicity to a licensed pneumococcal vaccine (Prevnar 20).
Pneumococcal Vaccine-Naive Individuals 50 Years Of Age And Older
In Study 1, 2,362 pneumococcal vaccine-naive individuals 50 years of age and older were randomized to receive either CAPVAXIVE or Prevnar 20. [see ADVERSE REACTIONS]
Table 4 summarizes the 21 serotype-specific OPA geometric mean antibody titers (GMTs) at 30 days postvaccination. The study demonstrated that CAPVAXIVE is noninferior to Prevnar 20 for the 10 shared serotype polysaccharides and induces statistically significantly greater OPA GMTs compared to Prevnar 20 for 10 of 11 serotype polysaccharides unique to CAPVAXIVE. Serotype 15C did not meet the criterion for statistical significance.
Table 5 summarizes the proportion of individuals who achieved a ≥4-fold rise from prevaccination to 1-month postvaccination for OPA responses. For 10 of 11 serotype polysaccharides unique to CAPVAXIVE, CAPVAXIVE induced statistically significantly greater OPA responses compared to Prevnar 20. Serotype 15C did not meet the criterion for statistical significance.
Table 4: Serotype-Specific OPA GMTs in Pneumococcal Vaccine-Naïve Individuals 50 Years of Age and Older (Study 1)
Pneumococcal
Serotype |
CAPVAXIVE
(N = 1179) |
Prevnar 20
(N = 1177) |
GMT Ratio* (CAPVAXIVE/Prevnar 20)
(95% CI)* |
|
n |
GMT* |
n |
GMT* |
|
| 10 Common Serotypes† |
|
| 3 |
1154 |
274.0 |
1161 |
176.7 |
1.55 (1.40, 1.72) |
| 6A |
1148 |
2302.0 |
1153 |
2972.5 |
0.77 (0.68, 0.88) |
| 7F |
1152 |
3637.4 |
1158 |
3429.9 |
1.06 (0.95, 1.18) |
| 8 |
1155 |
2501.3 |
1158 |
1811.1 |
1.38 (1.25, 1.53) |
| 10A |
1161 |
3893.4 |
1159 |
4678.0 |
0.83 (0.75, 0.93) |
| 11A |
1145 |
3232.6 |
1150 |
2092.8 |
1.54 (1.39, 1.72) |
| 12F |
1160 |
2641.2 |
1161 |
2499.6 |
1.06 (0.92, 1.21) |
| 19A |
1159 |
2136.1 |
1162 |
2817.8 |
0.76 (0.69, 0.84) |
| 22F |
1147 |
3874.5 |
1154 |
4770.1 |
0.81 (0.72, 0.92) |
| 33F |
1154 |
13558.9 |
1157 |
11742.1 |
1.15 (1.01, 1.32) |
| 11 Serotypes Unique to CAPVAXIVE ‡ |
|
| 9N |
1147 |
7470.7 |
1150 |
1640.4 |
4.55 (4.12, 5.04) |
| 15A |
1107 |
5237.2 |
1102 |
1589.0 |
3.30 (2.91, 3.74) |
| 15C |
1153 |
4216.2 |
1158 |
2072.3 |
2.03 (1.77, 2.34) |
| 16F |
1151 |
4868.2 |
1153 |
846.3 |
5.75 (5.16, 6.41) |
| 17F |
1148 |
7764.9 |
1156 |
460.4 |
16.86 (14.90, 19.09) |
| 20A |
1161 |
6099.2 |
1155 |
631.1 |
9.66 (8.66, 10.79) |
| 23A |
1132 |
3737.2 |
1104 |
461.5 |
8.10 (6.86, 9.55) |
| 23B |
1160 |
1082.5 |
1160 |
107.3 |
10.09 (8.48, 12.00) |
| 24F |
1153 |
2728.6 |
1130 |
70.5 |
38.71 (33.87, 44.25) |
| 31 |
1153 |
3132.5 |
1154 |
144.4 |
21.69 (18.68, 25.18) |
| 35B |
1153 |
8527.8 |
1159 |
1383.0 |
6.17 (5.59, 6.80) |
* GMTs, GMT ratio, and 95% CI were estimated from a constrained Longitudinal Data Analysis model.
† Non-inferiority for the serotypes common to CAPVAXIVE and Prevnar 20 was based on the lower bound of the 2-sided 95% CI for the estimated GMT ratio (CAPVAXIVE/Prevnar 20) being >0.5.
‡ Statistically significantly greater OPA responses for the serotypes unique to CAPVAXIVE compared to Prevnar 20 were based on the lower bound of the 2-sided 95% CI for the estimated GMT ratio (CAPVAXIVE/Prevnar 20) being >2.0.
N=Number of individuals randomized and vaccinated; n=Number of individuals contributing to the analysis. |
Table 5: Pneumococcal Vaccine-Naïve Individuals 50 years of Age and Older With a ≥4-Fold Rise in OPA Responses for Serotypes Unique to CAPVAXIVE (Study 1)
| Pneumococcal Serotype |
CAPVAXIVE (N=1179) |
Prevnar 20 (N=1177) |
Percentage Point Difference (CAPVAXIVE – Prevnar 20) |
Observed Response
Percentage (m/n) |
Observed Response
Percentage (m/n) |
Estimate (95% CI)*,† |
| 9N |
64.7 (595/920) |
19.9 (195/978) |
44.7 (40.7, 48.6) |
| 15A |
66.7 (462/693) |
35.8 (253/706) |
30.9 (25.8, 35.8) |
| 15C |
83.4 (794/952) |
74.2 (695/937) |
9.2 (5.6, 12.9) |
| 16F |
71.9 (654/910) |
20.8 (200/961) |
51.1 (47.1, 54.9) |
| 17F |
75.8 (653/862) |
9.5 (90/952) |
66.3 (62.8, 69.6) |
| 20A |
67.3 (675/1003) |
9.6 (97/1011) |
57.7 (54.2, 61.1) |
| 23A |
78.9 (598/758) |
36.8 (270/734) |
42.2 (37.6, 46.6) |
| 23B |
85.5 (873/1021) |
49.6 (506/1021) |
35.9 (32.1, 39.6) |
| 24F |
80.5 (745/925) |
6.3 (55/872) |
74.2 (71.1, 77.1) |
| 31 |
76.5 (698/912) |
17.9 (171/954) |
58.6 (54.8, 62.1) |
| 35B |
60.0 (550/917) |
6.8 (67/988) |
53.2 (49.6, 56.6) |
* Estimated difference and CI were based on the stratified Miettinen & Nurminen method.
† Statistically significantly greater OPA responses were based on the lower bound of the 2-sided 95% CI of the differences (CAPVAXIVE – Prevnar 20) between the percentages of individuals with a ≥4-fold rise from prevaccination to 1-month postvaccination being >10 percentage points.
N=Number of individuals randomized and vaccinated; m=Number of individuals with the indicated response; n=Number of individuals contributing to the analysis |
In Study 1, 64.7% of individuals 50 years of age and older, who received CAPVAXIVE, had ≥4-fold rise in cross-reactive OPA titers for serotype 15B, which met the prespecified success criterion (lower bound of the 2-sided 95% CI of the proportion of individuals with a .4-fold rise in OPA responses is >50%). In a descriptive analysis, the S. pneumoniae serotype 15B OPA GMT was 4,400.6 following administration of CAPVAXIVE, and 4,640.0 following administration of Prevnar 20, with a GMT ratio of 0.95 (95% CI: 0.84, 1.07).
Pneumococcal Vaccine-Naive Individuals 18 Through 49 Years Of Age
In Study 1, pneumococcal vaccine-naive individuals 18 through 49 years of age were randomized in a 2:1 ratio to receive CAPVAXIVE or Prevnar 20. [See ADVERSE REACTIONS]
Effectiveness of CAPVAXIVE in individuals 18 through 49 years of age was assessed by a comparison of the OPA responses induced by CAPVAXIVE in this age group to the OPA responses of individuals 50 through 64 years of age. The OPA responses of individuals 18 through 49 years of age to each of 22 S. pneumoniae serotypes met the criteria for immunobridging as the lower bound of the 2-sided 95% CI for the GMT ratio for each serotype was >0.5 (see Table 6). The S. pneumoniae serotype 15B cross-reactive OPA GMT was 10,976.7 following administration of CAPVAXIVE in individuals 18 through 49 years of age and 5,438.9 following administration of CAPVAXIVE in individuals 50 through 64 years of age, with a GMT ratio of 2.02 (95% CI: 1.57, 2.60).
Table 6: Comparison of Serotype-Specific OPA GMTs in Pneumococcal Vaccine-Naïve Individuals 18 through 49 Years of Age to 50 through 64 Years of Age Who Received CAPVAXIVE (Study 1)
| Pneumococcal Serotype |
18 through 49 years
(N = 200) |
50 through 64 years
(N = 589) |
GMT Ratio*,†
(18 through 49 years / 50 through 64 years)
(95% CI)* |
|
n |
GMT* |
n |
GMT |
|
| 3 |
194 |
308.6 |
572 |
282.7 |
1.09 (0.90, 1.33) |
| 6A |
196 |
5289.6 |
569 |
2572.9 |
2.06 (1.61, 2.62) |
| 7F |
198 |
6447.2 |
571 |
4278.8 |
1.51 (1.23, 1.84) |
| 8 |
197 |
4516.0 |
571 |
3004.7 |
1.50 (1.26, 1.79) |
| 9N |
197 |
17283.2 |
570 |
8791.4 |
1.97 (1.59, 2.43) |
| 10A |
197 |
6808.1 |
575 |
4382.6 |
1.55 (1.26, 1.92) |
| 11A |
196 |
5871.6 |
564 |
3785.8 |
1.55 (1.26, 1.91) |
| 12F |
196 |
6150.4 |
574 |
3561.2 |
1.73 (1.37, 2.17) |
| 15A |
184 |
11319.2 |
550 |
5901.2 |
1.92 (1.55, 2.37) |
| 15C |
195 |
10194.0 |
570 |
5708.0 |
1.79 (1.36, 2.35) |
| 16F |
193 |
8877.0 |
571 |
5720.0 |
1.55 (1.26, 1.91) |
| 17F |
194 |
16070.6 |
568 |
10068.0 |
1.60 (1.26, 2.02) |
| 19A |
198 |
2773.2 |
574 |
2374.6 |
1.17 (0.97, 1.40) |
| 20A |
197 |
13150.0 |
575 |
7562.7 |
1.74 (1.39, 2.18) |
| 22F |
198 |
9299.6 |
568 |
4683.6 |
1.99 (1.58, 2.49) |
| 23A |
192 |
8848.7 |
561 |
4739.5 |
1.87 (1.43, 2.44) |
| 23B |
198 |
2140.1 |
575 |
1420.9 |
1.51 (1.11, 2.04) |
| 24F |
197 |
4137.6 |
570 |
3047.2 |
1.36 (1.10, 1.67) |
| 31 |
195 |
8005.6 |
570 |
3820.7 |
2.10 (1.63, 2.69) |
| 33F |
197 |
34805.5 |
570 |
17607.4 |
1.98 (1.52, 2.57) |
| 35B |
198 |
13933.4 |
573 |
9053.9 |
1.54 (1.26, 1.87) |
* GMTs, GMT ratio, and 95% CI were estimated from a Longitudinal Data Analysis model.
† Immunobridging was based on the lower bound of the 2-sided 95% CI for the estimated GMT ratio (18 through 49 years / 50 through 64 years) being >0.5.
N=Number of individuals randomized and vaccinated; n=Number of individuals contributing to the analysis. |
Individuals 50 Years Of Age And Older With Prior Pneumococcal Vaccination
Study 3, a descriptive Phase 3 study, enrolled individuals 50 years of age and older who were previously vaccinated with other pneumococcal vaccines at least 1 year prior to study entry. Participants were enrolled into 1 of 3 cohorts based on their pneumococcal vaccination history (cohort 1: PNEUMOVAX 23, cohort 2: Prevnar 13, or cohort 3: PNEUMOVAX 23 followed by or preceded by Prevnar 13, PNEUMOVAX 23 preceded by VAXNEUVANCE, or VAXNEUVANCE alone).
Participants in cohort 1 were randomized to receive CAPVAXIVE (n=231) or VAXNEUVANCE (n=119), participants in cohort 2 were randomized to receive CAPVAXIVE (n=176) or PNEUMOVAX 23 (n=85), and participants in cohort 3 were allocated to receive CAPVAXIVE (n=106).
In each of the 3 cohorts, serotype-specific OPA GMTs and the proportion of individuals with .4-fold rise in OPA responses from baseline to 1-month postvaccination were assessed. In Cohort 1, CAPVAXIVE elicited OPA responses that were comparable to VAXNEUVANCE for the 6 common serotypes, and higher for the 15 unique serotypes and serotype 15B. In Cohort 2, CAPVAXIVE elicited OPA responses comparable to PNEUMOVAX 23 for the 12 common serotypes and serotype 15B, and higher for the 9 unique serotypes. OPA responses to CAPVAXIVE were similar across the 3 cohorts of participants who previously received one or more pneumococcal vaccines.
Concomitant Vaccination
In a double-blind study (Study 4), 1,080 individuals 50 years of age and older, with or without a history of prior pneumococcal vaccination, were randomized in a 1:1 ratio. One vaccination group received CAPVAXIVE and QIV concomitantly, followed by placebo 30 days later (concomitant group). A second vaccination group received QIV and placebo concomitantly, followed by CAPVAXIVE 30 days later (sequential group). Antibody responses were assessed 1-month postvaccination.
The OPA responses to CAPVAXIVE administered concomitantly with QIV were non-inferior to the OPA responses to CAPVAXIVE administered sequentially after QIV for 20 of 21 serotypes [lower bound of the 2-sided 95% CI of the GMT ratio (concomitant group/sequential group) was >0.5]; the non-inferiority was not met for serotype 23B [lower bound of the 2-sided 95% CI of the GMT ratio (concomitant group/sequential group) was 0.44]. The OPA response to serotype 15B was not assessed for non-inferiority. In a descriptive analysis, the OPA GMT in the concomitant group was 3,438.7 and in the sequential group was 4,440.5, with a GMT ratio of 0.77 (95% CI: 0.64, 0.94). The influenza strain-specific hemagglutination inhibition (HAI) responses to QIV administered concomitantly with CAPVAXIVE were non-inferior to the HAI responses to QIV administered alone for 3 of 4 influenza strains [lower bound of the 2-sided 95% CIs for HAI GMT ratios (concomitant group/sequential group) was >0.67 (non-inferiority margin); the lower bound was 0.67 for the A/H3N2 influenza strain].