Pharmacotherapeutic group: Vaccines, Influenza vaccine, ATC code: J07BB02
Mechanism of action
Supemtek TIVr contains recombinant HA proteins of the three strains of influenza virus specified by health authorities for inclusion in the annual seasonal vaccine. These proteins function as antigens which induce a humoral immune response, measured by hemagglutination inhibition (HI) antibody that is known to protect against influenza infection.
Antibodies against one influenza virus type or subtype confer limited or no protection against another. Furthermore, antibodies to one antigenic variant of influenza virus might not protect against a new antigenic variant of the same type or subtype. Frequent development of antigenic variants through antigenic drift is the virologic basis for seasonal epidemics and the reason for the usual replacement of one or more influenza virus strains in each year's influenza vaccine. Therefore, influenza vaccines are standardised to contain the haemagglutinins of influenza virus strains (i.e., typically two type A and one type B), representing the influenza viruses likely to be circulating in the upcoming season.
Immunogenicity studies performed with quadrivalent recombinant influenza vaccine (Supemtek)
Supemtek was evaluated in healthy adults of 18-49 years of age in a randomised, observer-blind, active controlled, non-inferiority immunogenicity, multi-center trial conducted during the 2014-2015 influenza season in the United States (study 1).
In the study 1, subjects received Supemtek (N=998) or an egg-based quadrivalent inactivated influenza vaccine (IIV4) (N=332). Immunogenicity was assessed before and 28 days after administration of a single dose of study vaccine.
Haemagglutination inhibition (HAI) geometric mean titers (GMTs) were determined for the two vaccine groups for each vaccine antigen. Immunogenicity was compared by calculating the difference in seroconversion rates (SCR) and the ratios of GMTs of Comparator to Supemtek.
Study 1 had two co-primary endpoints: GMTs and Day 28 HAI seroconversion rates for each of the four antigens contained in the study vaccines.
Supemtek met the success criterion for GMTs for three of the four antigens but did not meet the success criteria for the B/Victoria lineage antigen (Table 2). Antibody titres against the B/Victoria were low in both vaccine groups.
Table 2: Comparison of Day 28 Post-Vaccination Geometric Mean Titers (GMT) for Supemtek (quadrivalent recombinant influenza vaccine) and Comparator in Adults 18-49 Years of Age, Study 1 (Immunogenicity Population) 1,2,3
| Antigen | Post-vaccination GMT Supemtek N=969 | Post-vaccination GMT Comparator N=323 | GMT Ratio Comparator/ Supemtek (95% CI) |
| A/H1N1 | 493 | 397 | 0.81 (0.71, 0.92) |
| A/H3N2 | 748 | 377 | 0.50 (0.44, 0.57) |
| B/Yamagata | 156 | 134 | 0.86 ( 0.74, 0.99) |
| B/Victoria | 43 | 64 | 1.49 (1.29, 1.71) |
Abbreviations: CI, confidence interval; GMT, geometric mean titer.
1 HI titers were assayed using egg-derived antigens.
2 Comparator: egg-based quadrivalent inactivated influenza vaccine.
3 Success in meeting the GMTs endpoint was pre-defined as an upper bound (UB) of the two-sided 95% CI of GMTComparator / GMT Supemtek ≤ 1.5.
Supemtek met the success criterion for SCRs for three of the four antigens (Table 3), but not for the B/Victoria lineage. The HAI response to the B/Victoria lineage antigen was low in both vaccine groups.
Table 3: Comparison of Day 28 Seroconversion Rates for Supemtek (quadrivalent recombinant influenza vaccine) and Comparator in Adults 18-49 Years of Age, Study 1 (Immunogenicity Population) 1,2,3,4
| Antigen | SCR (%, 95% CI) Supemtek N=969 | SCR (%, 95% CI) Comparator N=323 | SCR Difference (%) Comparator - Supemtek [95% CI] |
| A/H1N1 | 66.7 (63.6, 69.6) | 63.5 (58.0, 68.7) | -3.2 (-9.2, 2.8) |
| A/H3N2 | 72.1 (69.2, 74.9) | 57.0 (51.4, 62.4) | -15.2 (-21.3, -9.1) |
| B/Yamagata | 59.6 (56.5, 62.8) | 60.4 (54.8, 65.7) | 0.7 (-5.4, 6.9) |
| B/Victoria | 40.6 (37.4, 43.7) | 58.2 (52.6, 63.6) | 17.6 (11.4, 23.9) |
Abbreviations: CI, confidence interval; SCR, seroconversion rate
1 HI titers were assayed using egg-derived antigens.
2 Comparator was an egg-based quadrivalent inactivated influenza vaccine.
3 Seroconversion was defined as either a pre-vaccination HAI titer of <1:10 and a post-vaccination HAI titer of ≥1:40, or a pre-vaccination HAI titer of ≥1:10 and a minimum 4- fold rise in post vaccination HAI titer, at Day 28.
4 Success in meeting the seroconversion rate (SCR) endpoint was pre-defined as an upper bound (UB) of the two-sided 95% CI of SCR Comparator – SCR Supemtek ≤10%.
The study 1 in adults 18-49 years of age was conducted in parallel to the study 2 in adults of 50 years of age and older. These adults 18-49 years of age were vaccinated during the same influenza season (2014-2015 Northern Hemisphere influenza season) and received the same Supemtek quadrivalent formulation (same vaccine strain composition) as adults of 50 years of age and older in the study 2. The immune response induced by Supemtek was assessed by the same HAI assay and performed by the same laboratory for both studies. The immunogenicity results in adults 18-49 years of age (study 1) and adults 50 years of age and older (study 2) are presented in table 4.
Table 4: Summary of HAI Antibody Response to Supemtek (quadrivalent recombinant influenza vaccine) for Each Strain in Adults 18-49 years (Study 1) and Adults≥50 years (Study 2) - Immunogenicity Analysis Set
| | Adults 18-49 years N=969 | Adults ≥50 years N=314 |
| GMT post-vaccination (95% CI) | | |
| A/California/7/2009 (H1N1) | 493 (460; 527) | 190 (164; 221) |
| A/Texas/50/2012 (H3N2) | 748 (700; 800) | 522(462; 589) |
| B/Massachusetts/02/2012 (Yamagata lineage) | 156 (145; 168) | 55 (48; 64) |
| B/Brisbane/60/2008 (Victoria lineage) | 43 (40; 46) | 29 (26; 33) |
| SCR % (95% CI) | | |
| A/California/7/2009 (H1N1) | 66.7 (63.6; 69.6) | 44.9 (39.3; 50.6) |
| A/Texas/50/2012 (H3N2) | 72.1 (69.2; 74.9) | 54.5 (48.8; 60.1) |
| B/Massachusetts/02/2012 (Yamagata lineage) | 59.6 (56.5; 62.8) | 38.9 (33.4; 44.5) |
| B/Brisbane/60/2008 (Victoria lineage) | 40.6 (37.4; 43.7) | 21.0 (16.6; 25.9) |
| GMTR % (95% CI) | | |
| A/California/7/2009 (H1N1) | 8.35 (7.59; 9.19) | 4.31 (3.71; 5.02) |
| A/Texas/50/2012 (H3N2) | 10.1 (9.12; 11.1) | 6.01 (5.03; 7.18) |
| B/Massachusetts/02/2012 (Yamagata lineage) | 3.59 (3.35; 3.85) | 2.16 (1.94; 2.40) |
| B/Brisbane/60/2008 (Victoria lineage) | 5.89 (5.43; 6.40) | 3.18 (2.81; 3.59) |
N=number of subjects with available data for the considered endpoint
GMT: Geometric Mean Titer; CI: Confidence Interval; SCR: Seroconversion rate; GMTR: Geometric Mean Titer of individuals ratios (post dose / pre dose)
These immunogenicity data provide supportive information for the 18-49 years of age group in addition to vaccine efficacy data available in adults ≥ 50 years of age (see Clinical Efficacy).
Clinical efficacy of Supemtek (quadrivalent recombinant influenza vaccine)
The efficacy of Supemtek (quadrivalent recombinant influenza vaccine) is relevant to Supemtek TIVr because both vaccines are manufactured using the same process and have overlapping compositions.
Supemtek efficacy in terms of prevention of laboratory-confirmed influenza-like illness (ILI) caused by any strain of influenza, was evaluated in adults ≥ 50 years of age and conducted during the 2014-2015 influenza season in the United States (study 2).
A total of 8963 healthy, medically stable adults were randomised in a 1:1 ratio to receive a single dose of Supemtek (n=4474) or an egg-based quadrivalent inactivated influenza vaccine (n=4489).
A total of 5412 (60.4%) subjects were 50-64 years of age, 2532 (28.2%) were 65-74 years of age and 1019 (11.4 %) were ≥ 75 years of age.
The primary efficacy endpoint of Study 2 was reverse transcriptase polymerase chain reaction (rtPCR)-positive, protocol-defined ILI due to any strain of influenza.
Laboratory-confirmed protocol defined ILI was defined as having at least one symptom in each of two categories of respiratory and systemic symptoms, which could include sore throat, cough, sputum production, wheezing and difficulty breathing, or systemic symptoms such as fever > 99°F (>37°C) , chills, fatigue, headache and myalgia, laboratory-confirmed by rtPCR.
US epidemiological data for the 2014-2015 influenza season indicated that Influenza A (H3N2) viruses predominated and that most influenza A/H3N2 viruses were antigenically dissimilar while A/H1N1 and B viruses were antigenically similar to vaccine antigens. Supemtek met the pre-specified success criterion for non-inferiority to the comparator pre-defined as a lower bound of the two sided 95% CI >-20%.
Of the 4474 participants exposed to Supemtek in a phase 3 active-controlled study (Study 2), a total of 1761 were 65 years or older. Although no differences in safety or efficacy were observed between older and younger participants, the number of patients aged 65 and over in this study was not sufficient to determine statistically whether this age group will respond differently from younger individuals.
Table 5: Relative Vaccine Efficacy (rVE) of Supemtek (quadrivalent recombinant influenza vaccine) versus Comparator against Laboratory-Confirmed Influenza, Regardless of Antigenic Similarity to Vaccine Antigens, Adults 50 Years of Age and Older, Study 2 (Efficacy Population)1,2
| | Supemtek (N=4303) | Comparator (N=4301) | RR | rVE % (95% CI) |
| n | Attack Rate % (n/N) | n | Attack Rate % (n/N) |
| All rtPCR-positive Influenza3 | 96 | 2.2 | 138 | 3.2 | 0.70 | 30 (105, 47) |
| All rtPCR-positive Influenza A3 | 73 | 1.7 | 114 | 2.7 | 0.64 | 36 (14, 53) |
| All rtPCR-positive Influenza B3 | 23 | 0.5 | 24 | 0.6 | 0.96 | 4 (-72, 46) |
| All Culture-confirmed Protocol-defined ILI3,4 | 58 | 1.3 | 101 | 2.3 | 0.57 | 43 (21, 59) |
Abbreviations: rtPCR=reverse transcriptase polymerase chain reaction; Comparator= an egg-based quadrivalent inactivated influenza vaccine; n=number of influenza cases; N=number of subjects in treatment group; RR=relative risk (Attack Rate Supemtek/Attack Rate IIV4); rVE = [(1-RR) x 100].
1 Excluded subjects with protocol deviations that could adversely affect efficacy.
2 Primary Analysis. All cases of rtPCR-confirmed influenza are included.
3 Post hoc analyses. All cases of influenza A were A/H3N2. Cases of influenza B were not distinguished by lineage.
4 Culture of rtPCR-positive samples was performed in MDCK cells.
5 The lower bound (LB) of the 95% confidence interval met the pre-specified, exploratory criterion for superior relative vaccine efficacy, LB > 9%.
Clinical efficacy of Supemtek TIVr (trivalent recombinant influenza vaccine)
The efficacy of Supemtek TIVr in protecting against influenza illness was evaluated in a randomised, observer-blind, placebo-controlled multicenter trial conducted in the United States during the 2007-2008 influenza season in adults 18-49 years of age (Study 3).
Study 3 enrolled and vaccinated 4648 healthy adults randomised in a 1:1 ratio to receive a single dose of Supemtek TIVr (n=2344) or saline placebo (n=2304).
The primary efficacy endpoint of Study 3 was defined as an influenza-like illness (ILI) with a positive culture for an influenza virus strain antigenically resembling a strain represented in Supemtek TIVr. ILI is defined as fever of ≥100°F (37.8°C) oral accompanied by cough, sore throat, or both, on the same or consecutive days. Attack rates and vaccine efficacy (VE), defined as the reduction in the influenza rate for RIV3 relative to placebo, were calculated for the total vaccinated cohort (n=4648).
Due to very small number of cultured confirmed influenza cases with matched strains, an exploratory analysis of VE of Supemtek TIVr against all strains, regardless of antigenic match, isolated from any subject with an ILI, not necessarily meeting ILI criteria was done, demonstrated an efficacy estimate of 44.8% (95% CI 24.4, 60.0). See Table 6 for VE by case definition.
Table 6: Vaccine Efficacy Against Culture-Confirmed Influenza in Healthy Adults 18-49 Years of Age, Study 31,3
| Case definition | Supemtek TIVr (N=2344) | Saline Placebo (N=2304) | Supemtek TIVr Vaccine Efficacy4 % | 95% Confidence Interval |
| Cases, n | Rate, % | Cases, n | Rate, % |
| Positive culture with a strain represented in the vaccine |
| CDC-ILI2, all matched strains5 Any ILI, all matched strains | 1 2 | 0.04 0.1 | 4 6 | 0.2 0.3 | 75.4 67.2 | (-148.0, 99.5) (-83.2, 96.8) |
| Positive culture with any strain, regardless of match to the vaccine |
| CDC-ILI2, all strains Sub-Type A Type B | 44 26 18 | 1.9 1.1 0.8 | 78 56 23 | 3.4 2.4 1.0 | 44.6 54.4 23.1 | (18.8, 62.6) (26.1, 72.5) (-49.0, 60.9) |
| Any ILI, all strains Sub-Type A Type B | 64 41 23 | 2.7 1.7 1.0 | 114 79 36 | 4.9 3.4 1.6 | 44.8 49.0 37.2 | (24.4, 60.0) (24.7, 65.9) (-8.9, 64.5) |
1 Vaccine efficacy (VE) = 1 minus the ratio of Supemtek TIVr /placebo infection rates (10).
2 Centers for Disease Control and Prevention - defined influenza-like illness (CDC-ILI) defined as fever of ≥100°F (37.8°C) oral accompanied by cough and/or sore throat, on the same day or on consecutive days.
3 The pre-defined success criterion for the primary efficacy analysis was that the lower bound of the 95% confidence interval (CI) of VE should be at least 40%.
4 Determined under the assumption of Poisson event rates, according to Breslow and Day, 1987.
5 Primary endpoint of trial.
Paediatric population
Supemtek (Quadrivalent recombinant influenza vaccine) was evaluated in healthy participants of age 9 to 17 years of age in a phase 3 non-randomised, open label, uncontrolled, multi-centre study (Study 4), enrolled a total of 1308 participants.
The primary objective was to demonstrate that vaccination with Supemtek induced an immune response (as assessed by haemagglutination inhibition [HAI], geometric mean titres [GMTs] and seroconversion [SCR] rates) in children and adolescents 9 to 17 years of age that was non-inferior to responses induced by Supemtek in adults 18 to 49 years of age for the 4 virus strains at Day 29 post-vaccination.
Non-inferiority of HAI immune response induced by Supemtek in children/adolescents 9 to 17 years of age relative to the immune response induced by Supemtek in adults 18 to 49 years of age was demonstrated for all four strains (Table 7 and 8).
Table 7: Comparison of Post vaccination HAI GMTs* of 9 to 17 years vs 18 to 49 years, Study 4 (Per-Protocol Analysis Set)†
| Antigen/strain | GMT 9 to 17 years (N=609) | GMT 18 to 49 years (N=606) | GMT Ratio 9 to 17 years / 18 to 49 years (95% CI) |
| A/H1N1 | 1946 | 982 | 1.98(1.73; 2.27) |
| A/H3N2 | 1975 | 604 | 3.27 (2.76; 3.87) |
| B/Victoria | 405 | 258 | 1.57 (1.35; 1.82) |
| B/Yamagata | 1941 | 1593 | 1.22 (1.09; 1.37) |
Abbreviations: CI, confidence interval; GMT, geometric mean titer.
* Non-inferiority demonstrated based on pre-specified criteria (lower limit of the 2-sided 95% CIs of the ratios of GMTs between age groups (9 to 17 years/18 to 49 years) > 0.667.
† The per-protocol analysis set is the subset of the full analysis set population with no major and/or critical deviations affecting immunogenicity.
Table 8: Comparison of seroconversion rates* after vaccination of 9 to 17 years vs 18 to 49 years, Study 4 (Per-Protocol Analysis Set)†
| Antigen/strain | SCR %, (95% CI) 9 to 17 years (N=609) | SCR %, (95% CI) 18 to 49 years (N=606) | SCR Difference (%) 9 to 17 years minus 18 to 49 years (95% CI) |
| A/H1N1 | 78.3 (74.8 ; 81.5) | 76.4 (72.8 ; 79.7) | 1.92 (-2.78; 6.62) |
| A/H3N2 | 86.5 (83.6 ; 89.1) | 87.1 (84.2 ; 89.7) | -0.59 (-4.41; 3.23) |
| B/Victoria | 76.8 (73.3 ; 80.1) | 73.6 (69.8 ; 77.0) | 3.29 (-1.57; 8.14) |
| B/Yamagata | 77.2 (73.6 ; 80.5) | 62.9 (58.9 ; 66.7) | 14.3 (9.17; 19.3) |
Abbreviations: CI, confidence interval; SCR, seroconversion rates
Seroconversion is defined as either a pre-dose titer < 1:10 at Day 1 and a post-dose titer ≥ 1:40 at Day 29 or a pre-dose titer ≥ 1:10 at Day 29 and >= 4-fold increase in post-vaccination titer
* Non-inferiority demonstrated based on pre-specified criteria of lower limit of the 2-sided 95% CI of the difference in seroconversion rates > -10 at Day 29 post-vaccination
† The per-protocol analysis set is the subset of the full analysis set population with no major and/or critical deviations affecting immunogenicity.
Supemtek induced a robust immune response in both age groups irrespective of age subgroup, sex, race, serological status at baseline, or prior influenza vaccination status.
Safety and immunogenicity of Supemtek has been evaluated in children 3 to 8 years of age. The data showed that while Supemtek induced an immune response in children 3 to 8 years of age, 1 or 2 doses of Supemtek did not induce an acceptable level of immunogenicity versus the IIV4 vaccine for all strains (see sections 4.2).