| Pharmacotherapeutic group: pneumococcal vaccines, ATC code: J07AL52 Epidemiological data The 10 pneumococcal serotypes included in this vaccine represent the major disease-causing serotypes in Europe covering approximately 56% to 90% of invasive pneumococcal disease (IPD) in children <5 years of age. In this age group, serotypes 1, 5 and 7F account for 3.3% to 24.1% of IPD depending on the country and time period studied.Acute otitis media (AOM) is a common childhood disease with different aetiologies. Bacteria can be responsible for 60-70% of clinical episodes of AOM. Streptococcus pneumoniae and Non-Typeable Haemophilus influenzae (NTHi) are the most common causes of bacterial AOM worldwide.1. Invasive pneumococcal disease (which includes sepsis, meningitis, bacteraemic pneumonia and bacteraemia)The protective efficacy of Synflorix against IPD has not been studied. As recommended by WHO, the assessment of potential efficacy against IPD has been based on a comparison of immune responses to the seven serotypes shared between Synflorix and another pneumococcal conjugate vaccine for which protective efficacy was evaluated previously (i.e. 7-valent Prevenar). Immune responses to the extra three serotypes in Synflorix have also been measured.In a head-to-head comparative trial with 7-valent Prevenar, non inferiority of the immune response to Synflorix measured by ELISA was demonstrated for all serotypes, except for 6B and 23F (upper limit of the 96.5% CI around the difference between groups >10%) (Table 1). For serotypes 6B and 23F, respectively, 65.9% and 81.4% of infants vaccinated at 2, 3 and 4 months reached the antibody threshold (i.e. 0.20 µg/ml) one month after the third dose of Synflorix versus 79.0% and 94.1% respectively, after three doses of 7-valent Prevenar. The clinical relevance of these differences is not known. The percentage of vaccinees reaching the threshold for the three additional serotypes in Synflorix (1, 5 and 7F) was respectively 97.3%, 99.0% and 99.5% and was at least as good as the aggregate 7-valent Prevenar response against the 7 common serotypes (95.8%). Table 1: Comparative analysis between 7-valent Prevenar and Synflorix in percentage of subjects with antibody concentrations > 0.20 µg/ml one month post-dose 3| Antibody
| SYNFLORIX
| 7-valent Prevenar
| Difference in % 0.20μg/ml (7-valent Prevenar minus SYNFLORIX)
| | N
| %
| N
| %
| %
| 96.5%CI
| | Anti-4
| 1106
| 97.1
| 373
| 100
| 2.89
| 1.71
| 4.16
| | Anti-6B
| 1100
| 65.9
| 372
| 79.0
| 13.12
| 7.53
| 18.28
| | Anti-9V
| 1103
| 98.1
| 374
| 99.5
| 1.37
| -0.28
| 2.56
| | Anti-14
| 1100
| 99.5
| 374
| 99.5
| -0.08
| -1.66
| 0.71
| | Anti-18C
| 1102
| 96.0
| 374
| 98.9
| 2.92
| 0.88
| 4.57
| | Anti-19F
| 1104
| 95.4
| 375
| 99.2
| 3.83
| 1.87
| 5.50
| | Anti-23F
| 1102
| 81.4
| 374
| 94.1
| 12.72
| 8.89
| 16.13
| Post-primary antibody geometric mean concentrations (GMCs) elicited by Synflorix against the seven serotypes in common were lower than those elicited by 7-valent Prevenar. Pre-booster GMCs (8 to 12 months after the last primary dose) were generally similar for the two vaccines. After the booster dose the GMCs elicited by Synflorix were lower for most serotypes in common with 7-valent Prevenar.In the same study, Synflorix was shown to elicit functional antibodies to all vaccine serotypes. For each of the seven serotypes in common, 87.7% to 100% of Synflorix vaccinees and 92.1% to 100% of 7-valent Prevenar vaccinees reached an OPA titre 8 one month after the third dose. The difference between both vaccines in terms of percentage of subjects with OPA titres 8 was <5% for all serotypes in common, including 6B and 23F. Post-primary and post-booster OPA antibody geometric mean titres (GMTs) elicited by Synflorix were lower than those elicited by 7-valent Prevenar for the seven shared serotypes, except for serotype 19F.For serotypes 1, 5 and 7F, the percentages of Synflorix vaccinees reaching an OPA titre 8 were respectively 65.7%, 90.9% and 99.6% after the primary vaccination course and 91.0%, 96.3% and 100% after the booster dose. The OPA response for serotypes 1 and 5 was lower in magnitude than the response for each of the other serotypes. The implications of these findings for protective efficacy are not known. The response to serotype 7F was in the same range as for the seven serotypes in common between the two vaccines.The administration of a fourth dose (booster dose) in the second year of life elicited an anamnestic antibody response as measured by ELISA and OPA for the 10 serotypes included in the vaccine demonstrating the induction of immune memory after the three-dose primary course.2. Acute Otitis Media (AOM) In a large randomised double-blind Pneumococcal Otitis Media Efficacy Trial (POET) conducted in the Czech Republic and in Slovakia, 4,968 infants received an 11-valent investigational vaccine (11Pn-PD) containing the 10 serotypes of Synflorix (along with serotype 3 for which efficacy was not demonstrated) or a control vaccine (hepatitis A vaccine) according to a 3, 4, 5 and 12-15 months vaccination schedule.Efficacy of the 11 Pn-PD vaccine against the first occurrence of vaccine-serotype AOM episode was 52.6% (95% CI: 35.0;65.5). Serotype specific efficacy against the first AOM episode was demonstrated for serotypes 6B (86.5%, 95%CI: 54.9;96.0), 14 (94.8%, 95% CI: 61.0;99.3), 19F (43.3%, 95% CI:6.3;65.4) and 23F (70.8%, 95% CI: 20.8;89.2). For other vaccine serotypes, the number of AOM cases was too limited to allow any efficacy conclusion to be drawn. Efficacy against any AOM episode due to any pneumococcal serotype was 51.5% (95% CI: 36.8;62.9). No increase in the incidence of AOM due to other bacterial pathogens or non-vaccine serotypes was observed in this study. The estimated vaccine efficacy against any clinical episodes of otitis media regardless of aetiology was 33.6% (95% CI: 20.8; 44.3).Based on immunological bridging of the functional vaccine response (OPA) of Synflorix with the 11-valent formulation used within POET, it is expected that Synflorix provides similar protective efficacy against pneumococcal AOM. 3. Additional immunogenicity data Infants from 6 weeks to 6 months of age 3-dose primary schedule In total eight studies, conducted in various countries across Europe, in Chile and in the Philippines, have evaluated the immunogenicity of Synflorix after a three-dose primary series (N=3,089) according to different vaccination schedules (6-10-14 weeks, 2-3-4, 3-4-5 or 2-4-6 months of age). A fourth (booster) dose was given in six clinical studies to 1,976 subjects. In general, comparable vaccine responses were observed for the different schedules, although somewhat higher immune responses were noted for the 2-4-6 month schedule.2-dose primary schedule The immunogenicity of Synflorix following a 2-dose primary vaccination schedule in subjects less than 6 months of age was evaluated in two clinical studies. In the first study, in a post-hoc analysis, the immunogenicity two months after the second dose of Synflorix was compared with 7-valent Prevenar and the percentages of subjects with ELISA antibody concentration 0.2 μg/ml were within the same range for each of the serotypes common to both vaccines with the exception of serotypes 6B (64.1% for Synflorix and 30.7% for 7-valent Prevenar) and 18C (87.1% for Synflorix and 97.6% for 7-valent Prevenar). Antibody GMCs were similar in both groups, with the exception of some serotypes for which responses were higher (6B) or lower (4, 9V and 18C) in the Synflorix group. Similarly, the percentage of subjects reaching OPA titres 8 and the OPA GMTs two months post dose 2 was within the same range for each of the serotypes common to both vaccines, with the exception of 6B and 19F for which responses were higher in the Synflorix group.In the second study, the immunogenicity after two or three doses of Synflorix was compared. Although there was no significant difference between the two groups in the percentages of subjects with antibody concentration 0.20 μg/mL (ELISA), the percentages of subjects for serotypes 6B and 23F were lower than for the other serotypes (Table 2 and Table 3). The percentage of subjects with OPA titres 8 in 2-dose primed subjects compared to 3-dose primed subjects were lower for serotypes 6B, 18C and 23F (74.4%, 82.8%, 86.3% respectively for the 2-dose schedule and 88.9%, 96.2%, 97.7% respectively for the 3-dose schedule). Overall, the persistence of the immune response until the booster at 11 months of age was lower in the 2-dose primed subjects. In both schedules, a booster response indicative of immunological priming was observed for each serotype (Table 2 and Table 3). After the booster dose a lower percentage of subjects with OPA titres 8 wasobserved in the 2-dose schedule for serotypes 5 (87.2% versus 97.5% for the 3-dose primed subjects) and 6B (81.1% versus 90.3%), all other responses were comparable.Table 2: Percentage of 2-dose primed subjects with antibody concentrations 0.20 µg/ml one month post-primary and one month post-booster | Antibody
| 0.2μg/mL (ELISA)
| | Post-primary
| Post-booster
| | %
| 95% CI
| %
| 95%CI
| | Anti-1
| 97.4
| 93.4
| 99.3
| 99.4
| 96.5
| 100
| | Anti-4
| 98.0
| 94.4
| 99.6
| 100
| 97.6
| 100
| | Anti-5
| 96.1
| 91.6
| 98.5
| 100
| 97.6
| 100
| | Anti-6B
| 55.7
| 47.3
| 63.8
| 88.5
| 82.4
| 93.0
| | Anti-7F
| 96.7
| 92.5
| 98.9
| 100
| 97.7
| 100
| | Anti-9V
| 93.4
| 88.2
| 96.8
| 99.4
| 96.5
| 100
| | Anti-14
| 96.1
| 91.6
| 98.5
| 99.4
| 96.5
| 100
| | Anti-18C
| 96.1
| 91.6
| 98.5
| 100
| 97.7
| 100
| | Anti-19F
| 92.8
| 87.4
| 96.3
| 96.2
| 91.8
| 98.6
| | Anti-23F
| 69.3
| 61.3
| 76.5
| 96.1
| 91.7
| 98.6
|
Table 3: Percentage of 3-dose primed subjects with antibody concentrations 0.20 µg/ml one month post-primary and one month post-booster | Antibody
| 0.2μg/mL (ELISA)
| | Post-primary
| Post-booster
| | %
| 95% CI
| %
| 95%CI
| | Anti-1
| 98.7
| 95.3
| 99.8
| 100
| 97.5
| 100
| | Anti-4
| 99.3
| 96.4
| 100
| 100
| 97.5
| 100
| | Anti-5
| 100
| 97.6
| 100
| 100
| 97.5
| 100
| | Anti-6B
| 63.1
| 54.8
| 70.8
| 96.6
| 92.2
| 98.9
| | Anti-7F
| 99.3
| 96.4
| 100
| 100
| 97.5
| 100
| | Anti-9V
| 99.3
| 96.4
| 100
| 100
| 97.5
| 100
| | Anti-14
| 100
| 97.6
| 100
| 98.6
| 95.2
| 99.8
| | Anti-18C
| 99.3
| 96.4
| 100
| 99.3
| 96.3
| 100
| | Anti-19F
| 96.1
| 91.6
| 98.5
| 98.0
| 94.2
| 99.6
| | Anti-23F
| 77.6
| 70.2
| 84.0
| 95.9
| 91.3
| 98.5
| In the follow-up of the second study, the persistence of antibodies at 36-46 months of age was demonstrated in subjects that had received a 2-dose primary series followed by a booster dose with at least 83.7% of subjects remaining seropositive for vaccine serotypes. In subjects that had received a 3-dose primary series followed by a booster dose, at least 96.5% of the subjects remained seropositive for vaccine serotypes. A single dose of Synflorix, administered during the 4th year of life, as a challenge dose, elicited similar ELISA antibody GMCs when measured 7-10 days after challenge in 2-dose primed subjects and 3-dose primed subjects. These levels were higher than those seen after challenge of unprimed subjects. The fold increase in ELISA antibody GMCs and OPA GMTs, pre to post vaccination, was also similar in 2-dose primed subjects to that in 3-dose primed subjects. These results are indicative of immunological memory in primed subjects for all vaccine serotypes.The clinical consequences of the lower post-primary and post-booster immune responses observed after the two-dose primary schedule are not known. Previously unvaccinated older infants and children The immune responses in previously unvaccinated older children were evaluated in two clinical studies.One clinical study evaluated vaccination in children aged 7-11 months, 12-23 months and 2 to 5 years.In the 7-11 months group, children received 2 primary doses followed by a booster dose in the second year of life. The immune responses after the booster dose of Synflorix in this age group were generally similar to those observed after the booster dose in infants who had been primed with 3 doses below 6 months of age.The immune response elicited after two doses of Synflorix in children 12-23 months of age was comparable to the response elicited after three doses in infants, except for 18C and 19F for which responses were higher in the 12-23 months children. The need for a booster dose after two doses in children aged 12-23 months has not been established.In the 2 to 5 years group, where children received 1 dose of Synflorix, the ELISA antibody GMCs for 6 out of the 10 vaccine serotypes were similar to those achieved following a 3 dose vaccination schedule in infants while they were lower for 4 out of the 10 vaccine serotypes (serotypes 1, 5, 14 and 23F) than those achieved following a 3-dose vaccination schedule in infants. The OPA GMTs were similar or higher following a single dose than a 3 dose primary course in infants, except for serotype 5.The second clinical study showed that the administration of 2 doses with a 2 month interval starting at 36-46 months of age resulted in higher ELISA antibody GMCs and OPA GMTs than those observed one month after a 3 dose primary vaccination for each vaccine serotype. The proportion of subjects with an ELISA antibody concentration 0.20 µg/mL or an OPA titre 8 for each vaccine serotype was comparable or higher in the catch-up group than in the 3-dose primed infants.Long-term persistence of antibodies has not been investigated after administration of a primary series in infants plus booster or after a two-dose priming in older children.In a clinical study, it has been demonstrated that Synflorix can be safely administered as a booster dose in the second year of life to children who had received 3 primary doses of 7-valent Prevenar. This study has shown that the immune responses against the 7 common serotypes were comparable to those elicited by a booster dose of 7-valent Prevenar. However, children who received 7-valent Prevenar for the primary series would not be primed against the additional serotypes contained in Synflorix (1, 5, 7F). Therefore the degree and duration of protection against invasive pneumococcal disease and otitis media due to these three serotypes in children of this age group following a single dose of Synflorix cannot be predicted.4. Immunogenicity data in preterm infants Immunogenicity of Synflorix in very preterm (gestation period of 27-30 weeks) (N=42), preterm (gestation period of 31-36 weeks) (N=82) and full term (gestation period > 36 weeks) (N=132) infants was evaluated following a 3 dose primary vaccination course at 2, 4, 6 months of age. Immunogenicity following a fourth dose (booster dose) at 15 to 18 months of age was evaluated in 44 very preterm, 69 preterm and 127 full term infants.One month after primary vaccination (i.e. after the third dose), at least 92.7% of subjects achieved ELISA antibody concentrations 0.2 µg/ml and at least 81.7% achieved OPA titres 8 for all vaccine serotypes, except serotype 1 (at least 58.8% with OPA titres 8). Similar antibody GMCs and OPA GMTs were observed for all infants except lower antibody GMCs for serotypes 4, 5 and 9V in very preterms and serotype 9V in preterms and lower OPA GMT for serotype 5 in very preterms. The clinical relevance of these differences is not known.One month after the booster dose increases of ELISA antibody GMCs and OPA GMTs were seen for all serotypes, indicative of immunological memory. Similar antibody GMCs and OPA GMTs were observed for all infants except a lower OPA GMT for serotype 5 in very preterm infants. Overall, at least 97.6% of subjects achieved ELISA antibody concentrations 0.2µg/ml and at least 91.9% achieved OPA titres 8 for all vaccine serotypes.The European Medicines Agency has deferred the obligation to submit the results of studies with Synflorix in one or more subsets of the paediatric population in diseases caused by Streptococcus pneumoniae and in acute otitis media caused by Haemophilus influenzae (see section 4.2 for information on paediatric use). | |