Pharmacotherapeutic group: vaccines, pneumococcal vaccines, ATC code: J07AL52
Epidemiological data
The 10 pneumococcal serotypes included in this vaccine represent the major disease-causing serotypesin Europe covering approximately 56% to 90% of invasive pneumococcal disease (IPD) in children <5years of age. In this age group, serotypes 1, 5 and 7F account for 3.3% to 24.1% of IPD depending onthe country and time period studied.
Pneumonia of different aetiologies is a leading cause of childhood morbidity and mortality globally. Inprospective studies, Streptococcus pneumoniae was estimated to be responsible for 30-50% ofpneumonia cases.
Acute otitis media (AOM) is a common childhood disease with different aetiologies. Bacteria can beresponsible 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.
Efficacy and effectiveness in clinical trials
In a large-scale phase III/IV, double-blind, cluster-randomized, controlled, clinical trial in Finland(FinIP), children were randomised into 4 groups according to the two infant vaccination schedules[2-dose (3, 5 months of age) or 3-dose (3, 4, 5 months of age) primary schedule followed by a boosterdose as of 11 months of age] to receive either Synflorix (2/3rd of clusters) or hepatitis vaccines ascontrol (1/3rd of clusters). In the catch-up cohorts, children between 7-11 months of age at firstvaccine dose received Synflorix or hepatitis B control vaccine according to a 2-dose primary schedulefollowed by a booster dose and children between 12-18 months of age at first vaccine dose received2 doses of either Synflorix or hepatitis A control vaccine. Average follow-up, from first vaccination,was 24 to 28 months for invasive disease and hospital-diagnosed pneumonia. In a nested study, infantswere followed up till approximately 21 months of age to assess impact on nasopharyngeal carriage andphysician-diagnosed AOM reported by parents.
In a large-scale phase III, randomized, double-blind clinical trial (Clinical Otitis Media and
Pneumonia Study - COMPAS) conducted in Argentina, Panama and Colombia, healthy infants aged6 to 16 weeks received either Synflorix or hepatitis B control vaccine at 2, 4 and 6 months of agefollowed respectively by either Synflorix or hepatitis A control vaccine at 15 to 18 months of age.
Invasive pneumococcal disease (which includes sepsis, meningitis, bacteraemic pneumonia andbacteraemia)
Effectiveness/efficacy in infant cohort below 7 months of age at enrolment
Vaccine effectiveness or efficacy (VE) was demonstrated in preventing culture-confirmed IPD due tovaccine pneumococcal serotypes when Synflorix was given to infants in either 2+1 or 3+1 schedulesin FinIP or 3+1 schedule in COMPAS (see Table 1).
Table 1: Number of vaccine serotype IPD cases and vaccine effectiveness (FinIP) or efficacy(COMPAS) in infants below 7 months of age at enrolment receiving at least one vaccine dose(Infant total vaccinated cohort)
FinIP COMPAS
No. of IPD cases VE(95% CI) No. of IPD cases VE(95% CI)
Type of Synflorix Synflorix (2) Synflorix
IPD 3+1 2+1 Control 3+1 Controlschedule schedule 3+1 2+1 3+1
N N N schedule schedule schedule
N N schedule10,273 10,054 10,200 11,798 11,799
Vaccine 100%(3) 91.8%(4) (5)serotype 0 1 12 0 18 100%
IPD(1) (82.8; 100) (58.3; 99.6) (77.3; 100)
Serotype 0 0 5 100% 100%6B IPD (54.9; 100) (54.5; 100) 0 2 -
Serotype 0 0 4 100% 100% 100%14 IPD (39.6; 100) (43.3; 100) 0 9 (49.5; 100)
IPD Invasive Pneumococcal Disease
VE Vaccine effectiveness (FinIP) or efficacy (COMPAS)
N number of subjects per group
CI Confidence Interval(1) In FinIP apart from serotypes 6B and 14, culture-confirmed vaccine serotype IPD casesincluded 7F (1 case in the Synflorix 2+1 clusters), 18C, 19F and 23F (1 case of each in thecontrol clusters). In COMPAS, serotypes 5 (2 cases), 18C (4 cases) and 23F (1 case) weredetected in control group in addition to serotypes 6B and 14.
(2) the 2 groups of control clusters of infants were pooled(3) p-value<0.0001(4) p-value=0.0009(5) in the ATP cohort VE was 100% (95% CI: 74.3; 100; 0 versus 16 cases)
In FinIP the overall observed VE against culture-confirmed IPD was 100% (95% CI: 85.6; 100; 0versus 14 cases) for the 3+1 schedule, 85.8% (95% CI: 49.1; 97.8; 2 versus 14 cases) for the 2+1schedule and 93.0% (95% CI: 74.9; 98.9; 2 versus 14 cases) regardless of the primary vaccinationschedule. In COMPAS it was 66.7% (95% CI: 21.8; 85.9; 7 versus 21 cases).
Effectiveness following catch-up immunisation
Among the 15,447 children in the catch-up vaccinated cohorts, there were no culture-confirmed IPDcases in the Synflorix groups while 5 vaccine serotype IPD cases were observed in the control groups(serotypes 4, 6B, 7F, 14 and 19F).
PneumoniaEfficacy against pneumonia was assessed in COMPAS. The mean duration follow-up from 2 weekspost-dose 3 in the ATP cohort was 23 months (range from 0 to 34 months) for the interim analysis(IA) and 30 months (range from 0 to 44 months) for the end-of-study analysis. At the end of this IA orend-of-study ATP follow-up period, the mean age was 29 months (range from 4 to 41 months) and 36months (range from 4 to 50 months), respectively. The proportion of subjects who received the boosterdose in the ATP cohort was 92.3% in both analyses.
Efficacy of Synflorix against first episodes of likely bacterial Community Acquired Pneumonia (CAP)occurring from 2 weeks after the administration of the 3rd dose was demonstrated in the ATP cohort(P value ≤ 0.002) in the interim analysis (event-driven; primary objective).
Likely bacterial CAP (B-CAP) is defined as radiologically confirmed CAP cases with either alveolarconsolidation/pleural effusion on the chest X-ray, or with non-alveolar infiltrates but with C reactiveprotein (CRP) ≥ 40 mg/l.
The vaccine efficacy against B-CAP observed at the interim analysis is presented below (table 2).
Table 2: Numbers and percentages of subjects with first episodes of B-CAP occurring from2 weeks after the administration of the 3rd dose of Synflorix or control vaccine and vaccineefficacy (ATP cohort)
Synflorix Control vaccine
N=10,295 N=10,201 Vaccine efficacyn % (n/N) n % (n/N)240 2.3% 304 3.0% 22.0%(95% CI: 7.7; 34.2)
N number of subjects per groupn/% number/percentage of subjects reporting a first episode of B-CAP anytime from 2 weeks afterthe administration of the 3rd dose
CI Confidence Interval
In the interim analysis (ATP cohort), the vaccine efficacy against first episodes of CAP with alveolarconsolidation or pleural effusion (C-CAP, WHO definition) was 25.7% (95% CI: 8.4; 39.6) andagainst first episodes of clinically suspected CAP referred for X-ray was 6.7% (95% CI: 0.7; 12.3).
At the end-of-study analysis (ATP cohort), the vaccine efficacy (first episodes) against B-CAP was18.2% (95% CI: 4.1; 30.3), against C-CAP 22.4% (95% CI: 5.7; 36.1) and against clinically suspected
CAP referred for X-ray 7.3% (95% CI: 1.6; 12.6). Efficacy was 100% (95% CI: 41.9; 100) againstbacteraemic pneumococcal pneumonia or empyema due to vaccine serotypes. The protection against
B-CAP before booster dose and at the time or after booster dose was 13.6% (95% CI: -11.3; 33.0) and21.7% (95% CI: 3.4; 36.5) respectively. For C-CAP it was 15.1% (95% CI: -15.5; 37.6) and 26.3%(95% CI: 4.4; 43.2) respectively.
The reduction in B-CAP and C-CAP was greatest in children < 36 months of age (vaccine efficacy of20.6% (95% CI: 6.5; 32.6) and 24.2% (95% CI: 7.4; 38.0) respectively). Vaccine efficacy results inchildren > 36 months of age suggest a waning of protection. The persistence of protection against
B-CAP and C-CAP beyond the age of 36 months is currently not established.
The results of the COMPAS study, which was performed in Latin America, should be interpreted withcaution due to possible differences in epidemiology of pneumonia in different geographical locations.
In the FinIP study, vaccine effectiveness in reducing hospital-diagnosed pneumonia cases (identifiedbased on the ICD 10 codes for pneumonia) was 26.7% (95% CI: 4.9; 43.5) in the 3+1 infant scheduleand 29.3% (95% CI: 7.5; 46.3) in the 2+1 infant schedule. For catch-up vaccination, vaccineeffectiveness was 33.2% (95% CI: 3.0; 53.4) in the 7-11 month cohort and 22.4% (95% CI: -8.7; 44.8)in the 12-18 month cohort.
Acute Otitis Media (AOM)
Two efficacy studies, COMPAS and POET (Pneumococcal Otitis Media Efficacy Trial), wereconducted with pneumococcal conjugate vaccines containing protein D: Synflorix and aninvestigational 11-valent conjugate vaccine (which in addition contained serotype 3), respectively.
In COMPAS, 7,214 subjects [Total Vaccinated cohort (TVC)] were included in the AOM efficacyanalysis of which 5,989 subjects were in the ATP cohort (Table 3).
Table 3: Vaccine efficacy against AOM(1) in COMPAS
Vaccine efficacy
Type or cause of AOM (95% CI)
ATP(2)
Clinical AOM 16.1%(-1.1; 30.4)(3)
Any pneumococcal serotype 56.1%(13.4; 77.8)10 pneumococcal vaccine serotypes 67.1%(17.0; 86.9)(4)
Non-typeable Haemophilus influenzae (NTHi) 15.0%(-83.8; 60.7)
CI Confidence Interval(1) First episode(2) Follow up period for a maximum of 40 months from 2 weeks after third primary dose(3) Not statistically significant by pre-defined criteria (One sided p=0.032). However, in TVCcohort, vaccine efficacy against first clinical AOM episode was 19% (95% CI: 4.4; 31.4).(4) Not statistically significant.
In another large randomised double-blind trial (POET) conducted in the Czech Republic and in
Slovakia, 4,907 infants (ATP cohort) received either the 11-valent investigational vaccine (11Pn-PD)containing the 10 serotypes of Synflorix (along with serotype 3 for which efficacy was notdemonstrated) or a control vaccine (hepatitis A vaccine) according to a 3, 4, 5 and 12-15 monthsvaccination schedule.
Efficacy of the 11 Pn-PD vaccine against the first occurrence of vaccine serotype AOM episode was52.6% (95% CI: 35.0; 65.5). Serotype specific efficacy against the first AOM episode wasdemonstrated 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, thenumber of AOM cases was too limited to allow any efficacy conclusion to be drawn. Efficacy againstany AOM episode due to any pneumococcal serotype was 51.5% (95% CI: 36.8; 62.9). The vaccineefficacy against the first episode of NTHi AOM was 31.1% (95% CI: -3.7; 54.2, not significant).
Efficacy against any NTHi AOM episode was 35.3% (95% CI: 1.8; 57.4). The estimated vaccineefficacy 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 the11-valent formulation used within POET, it is expected that Synflorix provides similar protectiveefficacy against pneumococcal AOM.
No increase in the incidence of AOM due to other bacterial pathogens or non-vaccine/non-vaccinerelated serotypes was observed in either COMPAS (based on the few cases reported) or POET trial.
Effectiveness against physician-diagnosed AOM reported by parents was studied in the nested studywithin the FinIP trial. Vaccine effectiveness was 6.1% (95% CI: -2.7; 14.1) for the 3+1 schedule and7.4% (95% CI -2.8; 16.6) for 2+1 schedule for this AOM endpoint in the infant vaccinated cohort.
Impact on nasopharyngeal carriage (NPC)
The effect of Synflorix on nasopharyngeal carriage was studied in 2 double-blind randomised studiesusing an inactive control: in the nested study of FinIP in Finland (5,023 subjects) and in COMPAS(1,700 subjects).
In both COMPAS and the nested Finnish study, Synflorix reduced vaccine type carriage with anapparent increase in non-vaccine (excluding vaccine-related) serotypes observed after booster. Theresults were not statistically significant across all analyses in COMPAS. However, taken togetherthere was a trend for decrease in overall pneumococcal carriage.
In both studies there were significant decrease of individual serotypes 6B and 19F. In the nested
Finnish study, a significant reduction was also observed for individual serotypes 14, 23F and, in the3 dose primary schedule, for the cross-reactive serotype 19A.
In a clinical study NPC was assessed in HIV positive infants (N = 83) and HIV negative infants bornfrom HIV positive mothers (N = 101) and compared to HIV negative infants born from HIV negativemothers (N = 100). The HIV exposure or infection did not appear to alter the effect of Synflorix onpneumococcal carriage up to 24-27 months of age, i.e. up to 15 months following booster vaccination.
Effectiveness in post-marketing surveillance
In Brazil, Synflorix was introduced into the national immunisation programme (NIP) using a 3+1schedule in infants (2, 4, 6 months of age and a booster dose at 12 months) with a catch-up campaignin children up to 2 years of age. Based on almost 3 years of surveillance following Synflorixintroduction, a matched case-control study reported a significant decrease in culture or PCR confirmed
IPD due to any vaccine serotype, and IPD due to individual serotypes 6B, 14 and 19A.
Table 4: Summary of effectiveness of Synflorix for IPD in Brazil
Types of IPD(1) Adjusted Effectiveness(2)% (95% CI)
Any vaccine serotype IPD(3) 83.8% (65.9; 92.3)
- Invasive pneumonia or bacteraemia 81.3% (46.9; 93.4)
- Meningitis 87.7% (61.4; 96.1)
IPD due to individual serotypes(4)
- 6B 82.8% (23.8; 96.1)
- 14 87.7% (60.8; 96.1)
- 19A 82.2% (10.7; 96.4)(1) Culture or PCR confirmed IPD(2) The adjusted effectiveness represents the percent reduction in IPD in the Synflorix vaccinatedgroup compared to the unvaccinated group, controlling for confounding factors.(3) Culture or PCR confirmed cases for serotypes 4, 6B, 7F, 9V, 14, 18C, 19F and 23F contributed tothe analysis.(4) Individual serotypes for which statistical significance was reached in the effectiveness analysiscontrolling for confounding factors (no adjustment for multiplicity performed).
In Finland, Synflorix was introduced into NIP with a 2+1 schedule in infants (3, 5 months of age and abooster dose at 12 months) without catch-up campaign. Before and after NIP comparison suggests asignificant decrease in the incidence of any culture confirmed IPD, any vaccine serotype IPD and IPDdue to serotype 19A.
Table 5: Rates of IPD and the corresponding rate reductions in Finland
IPD Incidence per 100,000 person years Relative rate reduction(1)% (95% CI)
Before NIP After NIP
Any culture confirmed 62.9 12.9 80% (72; 85)
Any vaccine serotype(2) 49.1 4.2 92% (86; 95)
Serotype 19A 5.5 2.1 62% (20; 85)(1) The relative rate reduction indicates how much the incidence of IPD in children of ≤5 years of agewas reduced in the Synflorix cohort (followed for 3 years after NIP introduction) versus age andseason matched non-vaccinated historical cohorts (each followed for 3 year periods beforeintroduction of Synflorix into NIP).(2) Culture confirmed cases for serotypes 1, 4, 6B, 7F, 9V, 14, 18C, 19F and 23F contributed to theanalysis.
In Quebec, Canada, Synflorix was introduced into the infant immunisation programme (2 primarydoses to infants less than 6 months of age and a booster dose at 12 months) following 4.5 years of useof 7-valent Prevenar. Based on 1.5 years of surveillance following Synflorix introduction, with over90% coverage in the vaccine-eligible age group, a decrease in vaccine serotype IPD incidence (largelydue to changes in serotype 7F disease) was observed with no concomitant increase in non-vaccineserotype IPD incidence. Overall, the incidence of IPD was 35/100,000 person-years in those cohortsexposed to Synflorix, and 64/100,000 person-years in those exposed to 7-valent Prevenar, representinga statistically significant difference (p = 0.03). No direct cause-and-effect can be inferred fromobservational studies of this type.
Immunogenicity data
Immunologic non-inferiority to 7-valent Prevenar
The assessment of potential efficacy against IPD pre-licensure was based on a comparison of immuneresponses to the seven serotypes shared between Synflorix and another pneumococcal conjugatevaccine for which protective efficacy was evaluated previously (i.e. 7-valent Prevenar), asrecommended by the WHO. Immune responses to the extra three serotypes in Synflorix were alsomeasured.
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 limitof the 96.5% CI around the difference between groups >10%) (Table 6). For serotypes 6B and 23F,respectively, 65.9% and 81.4% of infants vaccinated at 2, 3 and 4 months reached the antibodythreshold (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 isunclear, as Synflorix was observed to be effective against IPD caused by serotype 6B in a double-blind, cluster-randomized clinical study (see Table 1).
The percentage of vaccinees reaching the threshold for the three additional serotypes in Synflorix (1, 5and 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 6: Comparative analysis between 7-valent Prevenar and Synflorix in percentage ofsubjects 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 sevenserotypes in common were lower than those elicited by 7-valent Prevenar. Pre-booster GMCs (8 to 12months after the last primary dose) were generally similar for the two vaccines. After the booster dosethe 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. Foreach of the seven serotypes in common, 87.7% to 100% of Synflorix vaccinees and 92.1% to 100% of7-valent Prevenar vaccinees reached an OPA titre ≥ 8 one month after the third dose. The differencebetween both vaccines in terms of percentage of subjects with OPA titres ≥ 8 was <5% for allserotypes in common, including 6B and 23F. Post-primary and post-booster OPA antibody geometricmean titres (GMTs) elicited by Synflorix were lower than those elicited by 7-valent Prevenar for theseven shared serotypes, except for serotype 19F.
For serotypes 1, 5 and 7F, the percentages of Synflorix vaccinees reaching an OPA titre ≥ 8 wererespectively 65.7%, 90.9% and 99.6% after the primary vaccination course and 91.0%, 96.3% and100% after the booster dose. The OPA response for serotypes 1 and 5 was lower in magnitude than theresponse for each of the other serotypes. The implications of these findings for protective efficacy arenot known. The response to serotype 7F was in the same range as for the seven serotypes in commonbetween the two vaccines.
It has also been demonstrated that Synflorix induces an immune response to the cross-reactiveserotype 19A with 48.8% (95% CI: 42.9; 54.7) of vaccinees reaching an OPA titre ≥ 8 one month aftera booster dose.
The administration of a fourth dose (booster dose) in the second year of life elicited an anamnesticantibody response as measured by ELISA and OPA for the vaccine serotypes and the cross-reactiveserotype 19A demonstrating the induction of immune memory after the three-dose primary course.
Additional immunogenicity data
Infants from 6 weeks to 6 months of age:
3-dose primary schedule
In clinical studies the immunogenicity of Synflorix was evaluated after a 3-dose primary vaccinationseries (6941 subjects) according to different schedules (including 6-10-14 weeks, 2-3-4, 3-4-5 or 2-4-6months of age) and after a fourth (booster) dose (5645 subjects) given at least 6 months after the lastprimary dose and from the age of 9 months onwards. In general, comparable vaccine responses wereobserved for the different schedules, although somewhat higher immune responses were noted for the2-4-6 month schedule.
2-dose primary schedule
In clinical studies the immunogenicity of Synflorix was evaluated after a 2-dose primary vaccinationseries (470 subjects) according to different schedules (including 6-14 weeks, 2-4 or 3-5 months of age)and after a third (booster) dose (470 subjects) given at least 6 months after the last primary dose andfrom the age of 9 months onwards.
A clinical study evaluated the immunogenicity of Synflorix in 2-dose or 3-dose primed subjects infour European countries. Although there was no significant difference between the two groups in thepercentages of subjects with antibody concentration ≥ 0.20 µg/ml (ELISA), the percentages of subjectsfor serotypes 6B and 23F were lower than for the other vaccine serotypes (Table 7 and Table 8). Thepercentage of subjects with OPA titres ≥ 8 in 2-dose primed subjects compared to 3-dose primedsubjects were lower for serotypes 6B, 18C and 23F (74.4%, 82.8%, 86.3% respectively for the 2-doseschedule and 88.9%, 96.2%, 97.7% respectively for the 3-dose schedule). Overall, the persistence ofthe immune response until the booster at 11 months of age was lower in the 2-dose primed subjects. Inboth schedules, a booster response indicative of immunological priming was observed for eachvaccine serotype (Table 7 and Table 8). After the booster dose a lower percentage of subjects with
OPA titres ≥ 8 was observed 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 7: Percentage of 2-dose primed subjects with antibody concentrations ≥ 0.20 µg/ml onemonth post-primary and one month post-booster≥ 0.20 µg/ml (ELISA)
Antibody 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 8: Percentage of 3-dose primed subjects with antibody concentrations ≥ 0.20 µg/ml onemonth post-primary and one month post-booster≥ 0.20 µg/ml (ELISA)
Antibody 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
For the cross-reactive serotype 19A, similar ELISA antibody GMCs were observed post-primary andpost-booster for the 2-dose schedule [0.14 µg/ml (95% CI: 0.12; 0.17) and 0.73 µg/ml (95% CI: 0.58;0.92)] and the 3-dose schedule [0.19 µg/ml (95% CI: 0.16; 0.24) and 0.87 µg/ml (95% CI: 0.69;1.11)]. The percentage of subjects with OPA titres ≥ 8 and GMTs observed post-primary and post-booster were lower in the 2-dose schedule than that in the 3-dose schedule. In both schedules, abooster response indicative of immunological priming was observed.
The clinical consequences of the lower post-primary and post-booster immune responses observedafter the 2-dose primary schedule are not known.
A clinical study conducted in South Africa assessed the immunogenicity of Synflorix after 3-dose (6-10-14 weeks of age) or 2-dose (6-14 weeks of age) priming followed by a booster dose at 9-10 monthsof age. After primary vaccination, for the vaccine serotypes the percentages of subjects reachingantibody threshold and with OPA titres ≥ 8 were similar after 2-dose compared to 3-dose except lower
OPA percentage for serotype 14. The antibody GMCs and OPA GMTs were lower after 2-dose formost vaccine serotypes.
For the cross-reactive serotype 19A, similar percentages of subjects reaching antibody threshold and
OPA titres ≥ 8 and similar antibody GMC and OPA GMT were observed post-primary in both groups.
Overall, the pre-booster persistence of immune responses was lower in the 2-dose compared to the3-dose priming group for most vaccine serotypes and was similar for serotype 19A.
Booster dose at 9-10 months of age
In the study conducted in South Africa, the booster dose given at 9-10 months of age induced markedincreases in antibody GMCs and OPA GMTs for each vaccine serotype and serotype 19A in both 2-dose and 3-dose priming groups indicative of immunological priming.
Booster dose at 9-12 versus 15-18 months of age
A clinical study conducted in India assessing a booster dose given at 9-12 or 15-18 months of age in66 and 71 children, respectively, following primary vaccination at 6, 10 and 14 weeks of age, did notsuggest differences between groups in terms of antibody GMCs. Higher OPA GMTs in the groupboosted at 15-18 months of age were observed for most of the vaccine serotypes and serotype 19A.
However, the clinical relevance of this observation is not known.
Immune memory
In the follow-up of the European study evaluating the 2-dose and 3-dose primary vaccinationschedules, the persistence of antibodies at 36-46 months of age was demonstrated in subjects that hadreceived a 2-dose primary series followed by a booster dose with at least 83.7% of subjects remainingseropositive for vaccine serotypes and the cross-reactive serotype 19A. In subjects that had received a3-dose primary series followed by a booster dose, at least 96.5% of the subjects remained seropositivefor vaccine serotypes and 86.4% for serotype 19A. After a single dose of Synflorix, administeredduring the 4th year of life, as a challenge dose, the fold increase in ELISA antibody GMCs and OPA
GMTs, pre to post vaccination, was similar in 2-dose primed subjects to that in 3-dose primedsubjects. These results are indicative of immunological memory in primed subjects for all vaccineserotypes and the cross-reactive serotype 19A.
Unvaccinated infants and children ≥ 7 months of age:
The immune responses elicited by Synflorix in previously unvaccinated older children were evaluatedin three clinical studies.
The first clinical study evaluated the immune responses for vaccine serotypes and the cross-reactiveserotype 19A in children aged 7-11 months, 12-23 months and 2 to 5 years:
* Children aged 7-11 months received 2 primary doses followed by a booster dose in thesecond year of life. The immune responses after the booster dose in this age group weregenerally similar to those observed after the booster dose in infants who had been primedwith 3 doses below 6 months of age.
* In children aged 12-23 months, the immune responses elicited after two doses werecomparable to the responses elicited after three doses in infants below 6 months of age,except for vaccine serotypes 18C and 19F as well as serotype 19A for which responseswere higher in the 12-23 months children.
* In children aged 2 to 5 years that received 1 dose, the ELISA antibody GMCs were similarfor 6 vaccine serotypes as well as serotype 19A than those achieved following a 3-dosevaccination schedule in infants below 6 months of age while they were lower for4 vaccine serotypes (serotypes 1, 5, 14 and 23F). The OPA GMTs were similar or higherfollowing a single dose than a 3-dose primary course in infants below 6 months of age,except for serotype 5.
In the second clinical study, a single dose administered four months after two catch-up doses at 12-20months of age elicited a marked increase of ELISA GMCs and OPA GMTs (when comparing theresponses pre and post the last dose), indicating that two catch-up doses provide adequate priming.
The third clinical study showed that the administration of 2 doses with a 2 month interval starting at36-46 months of age resulted in higher ELISA antibody GMCs and OPA GMTs than those observedone month after a 3-dose primary vaccination for each vaccine serotype and the cross-reactiveserotype 19A. 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 seriesin infants plus booster or after a 2-dose priming in older children.
In a clinical study, it has been demonstrated that Synflorix can be safely administered as a boosterdose in the second year of life to children who had received 3 primary doses of 7-valent Prevenar. Thisstudy has shown that the immune responses against the 7 common serotypes were comparable to thoseelicited by a booster dose of 7-valent Prevenar. However, children who received 7-valent Prevenar forthe 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 otitismedia due to these three serotypes in children of this age group following a single dose of Synflorixcannot be predicted.
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) infantswas 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 in44 very preterm, 69 preterm and 127 full term infants.
One month after primary vaccination (i.e. after the third dose), for each vaccine serotype at least92.7% of subjects achieved ELISA antibody concentrations ≥ 0.20 µg/ml and at least 81.7% achieved
OPA titres ≥ 8 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, 9V and thecross-reactive serotype 19A in very preterms and serotype 9V in preterms and lower OPA GMT forserotype 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 foreach vaccine serotype and the cross-reactive serotype 19A, indicative of immunological memory.
Similar antibody GMCs and OPA GMTs were observed for all infants except a lower OPA GMT forserotype 5 in very preterm infants. Overall, for each vaccine serotype at least 97.6% of subjectsachieved ELISA antibody concentrations ≥ 0.20 µg/ml and at least 91.9% achieved OPA titres ≥ 8.
Immunogenicity in special population
HIV positive (HIV+/+) infants and HIV negative infants born from HIV positive mothers (HIV+/-)
In a clinical study conducted in South Africa the immunogenicity of Synflorix administered as a3-dose primary vaccination course (at 6, 10 and 14 weeks of age) followed by a booster dose (at 9 to10 months of age) was assessed in 70 HIV positive (HIV+/+) infants, 91 HIV negative infants bornfrom HIV positive mothers (HIV+/-) and 93 HIV negative infants born from HIV negative mothers(HIV-/-). Only HIV+/+ infants with WHO classification stage 1 (asymptomatic) or 2 (mild symptoms)were to be enrolled.
For most vaccine serotypes, group comparisons did not suggest any differences in post-primaryimmune responses between the HIV+/+ and HIV-/- groups, or the HIV+/- and HIV-/- groups, exceptfor a trend towards a lower percentage of subjects reaching OPA titres ≥ 8 and lower OPA GMTs inthe HIV+/+ group. The clinical relevance of this lower post-primary OPA response is not known. Forthe cross-reactive serotype 19A, the results did not suggest any differences in ELISA antibody GMCsand OPA GMTs between groups.
The booster dose of Synflorix in HIV+/+ and HIV+/- infants induced robust increases in ELISAantibody GMCs and OPA GMTs for each vaccine serotype and serotype 19A indicative ofimmunological priming. For most vaccine serotypes and serotype 19A, group comparisons did notsuggest any differences post-booster dose in ELISA antibody GMCs and OPA GMTs between the
HIV+/+ and HIV-/- groups, or the HIV+/- and HIV-/- groups.
The results for protein D suggested comparable post-primary and post-booster immune responsesbetween groups.
In each group, persistence of the immune responses was observed at 24-27 months of age, i.e. up to 15months following booster vaccination.
Children with sickle cell disease
A clinical study conducted in Burkina Faso assessed the immunogenicity of Synflorix administered to146 children with SCD (haemoglobin SS disease, haemoglobin SC disease or with β-thalassemia)compared to 143 age-matched children without SCD. Among children with SCD, 48 children<6 months of age received primary vaccination at 8, 12 and 16 weeks of age, followed by a boosterdose at 9-10 months of age, 50 children aged 7-11 months and 48 aged 12-23 months startedcatch-up vaccination according to their age. The immune response to Synflorix for each of the vaccineserotypes and serotype 19A, as well as for protein D, did not appear to be influenced by SCD.
Children with splenic dysfunction
Immunogenicity and safety of Synflorix were assessed in a limited number of primed or unprimedsubjects with congenital or acquired asplenia, splenic dysfunction or complement deficiencies:6 subjects 2-5 years of age and 40 subjects 6-17 years of age (Synflorix is indicated up to 5 years ofage). Synflorix was shown to be immunogenic and no new safety concerns were observed in thisstudy.
Immunogenicity of Synflorix containing the preservative 2-phenoxyethanol (2-PE)
Immunogenicity of Synflorix containing the preservative 2-PE (presented in a 4-dose container) wasassessed in healthy infants vaccinated at 6, 10 and 18 weeks of age and compared to those receiving
Synflorix without added preservative (160 enrolled subjects per group).
Immune responses were compared using non-inferiority criteria in terms of antibody GMC ratio(GMC from group of subjects receiving Synflorix without 2-PE over GMC from group of subjectsreceiving Synflorix with 2-PE) for each of the 10 vaccine serotypes and for the cross-reactive serotype19A.
Non-inferiority was demonstrated as the upper limit of the 2-sided 95% CI of the antibody GMC ratioswas below 2 for each of the 10 vaccine serotypes and for serotype 19A. In addition, OPA GMTs werein same ranges for both groups.
Use of Synflorix and 13-valent PCV in the immunisation course of an individual
The use of Synflorix and PCV13 in the immunisation course of an individual (interchangeability) wasassessed in a clinical study conducted in Mexico. Infants were primed with 2 doses of PCV13 (86subjects) or 1 dose of PCV13 and 1 dose of Synflorix (89 subjects), followed by a booster dose of
Synflorix at 12-15 months of age, and compared to infants administered with a 2+1 Synflorixvaccination schedule.
For most of the 10 common serotypes 1 month post-priming and post-booster, observed percentages ofinfants reaching antibody concentrations ≥ 0.2 µg/mL and OPA titers above cutoffs were high forinfants receiving both Synflorix and PCV13: ≥ 97.7% for 8 out of 10 serotypes for antibodyconcentrations ≥ 0.2 µg/mL and ≥ 92.0% for 7 out of 10 serotypes for OPA titers above cutoffs.
For cross-reactive serotype 19A, these percentages were at least 86.5% and 88.0%, respectively.
No safety concern was identified when the vaccine was changed from PCV13 to Synflorix at the timeof priming or boosting.