Clinical Pharmacology for Fluzone Highdose
Mechanism Of Action
Influenza illness and its complications may follow influenza infection. Global surveillance of influenza viruses identifies yearly antigenic variants. Since 1977, antigenic variants of influenza A (H1N1 and H3N2) viruses and influenza B viruses have been in global circulation. Specific levels of hemagglutination inhibition (HI) antibody titer post-vaccination with inactivated influenza virus vaccines have not been correlated with protection from influenza virus infection. In some human studies, antibody titers ≥1:40 have been associated with protection from influenza illness in up to 50% of participants. (See REFERENCES 3 and 4)
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 change of one or more new strains in each year's influenza vaccine. Therefore, influenza vaccines are standardized to contain the hemagglutinins of influenza virus strains representing the influenza viruses likely to be circulating in the U.S. during the influenza season.
Fluzone High-Dose Quadrivalent stimulates the immune system to produce antibodies that help prevent influenza disease.
Clinical Studies
Immunogenicity Of Fluzone High-Dose Quadrivalent In Adults 65 Years Of Age And Older
Study 1 (NCT03282240, see https://clinicaltrials.gov) was a randomized, active-controlled, modified double-blind trial in adults 65 years of age and older conducted in the US. The study compared the safety and immunogenicity of Fluzone High-Dose Quadrivalent to those of Fluzone High-Dose. The objective was to demonstrate immunologic non-inferiority of Fluzone High-Dose Quadrivalent to Fluzone High- Dose, as assessed by HAI geometric mean antibody titers (GMTs) at Day 28 and seroconversion rates, to strains common to formulations of both vaccines, based on pre-specified criteria.
A total of 2670 adults from 65 years of age were randomized (4:1:1) to receive one dose of either Fluzone High-Dose Quadrivalent or one of two formulations of Fluzone High-Dose (one formulation contained a B strain of the Victoria lineage [TIV-HD1] while the other contained a B strain of the Yamagata lineage [TIV-HD2]).
Females accounted for 58.2% of participants in the Fluzone High-Dose Quadrivalent group and 57.4% of participants in the Fluzone High- Dose group (TIV-HD1 and TIV-HD2, pooled). The mean age was 72.9 years (range: 65 through 100 years) in the Fluzone High-Dose Quadrivalent group and the mean age was 73.0 (range: 65 through 95 years) in the Fluzone High-Dose group. The percentage of subjects 75 years of age or older was 35.4% in the Fluzone High-Dose Quadrivalent group and 35.8% in the Fluzone High-Dose group. Most participants were White (91.2% and 89.7%), followed by Black (6.8% and 8.0%), and Hispanic (2.8% and 2.6%) in the Fluzone High-Dose Quadrivalent and Fluzone High-Dose groups, respectively.
The immunogenicity results of Study 1 are summarized in Table 3 and Table 4 below.
Table 3: Study 1*: Post-vaccination HAI Antibody GMTs and Analyses of Non-inferiority of Fluzone High-Dose Quadrivalent Relative to Fluzone High-Dose, Adults 65 Years of Age and Older, Per-Protocol Analysis Set
| Influenza Strain | GMT | GMT Ratio | Met Predefined Non-inferiority Criteria† |
QIV-HD N¶ =1679-1680 | TIV-HD1‡ (B1 Victoria) N¶ =423 | TIV-HD2§ (B2 Yamagata) N¶ =430 | QIV-HD over TIV-HD (95% CI) |
| A (H1N1)# | 312 | 374 | 0.83 (0.744; 0.932) | Yes |
| A (H3N2)# | 563 | 594 | 0.95 (0.842; 1.066) | Yes |
| B1 (Victoria) | 516 | 476 | - | 1.08 (0.958; 1.224) | Yes |
| B2 (Yamagata) | 578 | - | 580 | 1.00 (0.881; 1.129) | Yes |
* NCT03282240 † Predefined noninferiority criterion for the GMT ratio: the lower limit of the 95% CI of the GMT ratio (QIV-HD divided by TIV-HD) is >0.667 ‡ TIV-HD1 contained A/Michigan/45/2015 (H1N1), A/Hong Kong/4801/2014 (H3N2), and B/Brisbane/60/2008 (B1, Victoria lineage) § TIV-HD2 contained A/Michigan/45/2015 (H1N1), A/Hong Kong/4801/2014 (H3N2), and B/Phuket/3073/2013 (B2, Yamagata lineage) ¶ N is the number of vaccinated participants with available data for the immunologic endpoint listed # Pooled TIV-HD group includes subjects vaccinated with either TIV-HD1 or TIV-HD2 for the A strain comparison |
Table 4: Study 1*: Seroconversion Rates and Analyses of Non-inferiority of Fluzone High-Dose Quadrivalent Relative to Fluzone High-Dose, Adults 65 Years of Age and Older, Per-Protocol Analysis Set
| Influenza Strain | Seroconversion Rates (Percentage)† | Difference of Seroconversion Ra | Met Predefined Non-inferiority Criteria‡ |
QIV-HD N# =1668-669 | TIV-HD1§ (B1 Victoria) N#=420-421 | TIV-HD2¶ (B2 Yamagata) N#=428 | QIV-HD minus TIV-HD (95% CI) |
| A (H1N1)Þ | 50.4 | 53.7 | -3.27 (-7.37; 0.86) | Yes |
| A (H3N2)Þ | 49.8 | 50.5 | -0.71 (-4.83; 3.42) | Yes |
| B1 (Victoria) | 36.5 | 39.0 | - | -2.41 (-7.66; 2.70) | Yes |
| B2 (Yamagata) | 46.6 | - | 48.4 | -1.75 (-7.04; 3.53) | Yes |
* NCT03282240 † Seroconversion Rates: For subjects with a pre-vaccination titer <10 (1/dil), proportion of subjects with a post-vaccination titer ≥40 (1/dil) and for subjects with a pre-vaccination titer ≥10 (1/dil), proportion of subjects with a ≥four-fold increase from pre-vaccination to postvaccination titer ‡ Predefined noninferiority criterion for seroconversion: the lower limit of the two-sided 95% CI of the difference of the seroconversion rates (QIV-HD minus TIV-HD) is >-10% § TIV-HD1 contained A/Michigan/45/2015 (H1N1), A/Hong Kong/4801/2014 (H3N2), and B/Brisbane/60/2008 (B1, Victoria lineage) ¶ TIV-HD2 contained A/Michigan/45/2015 (H1N1), A/Hong Kong/4801/2014 (H3N2), and B/Phuket/3073/2013 (B2, Yamagata lineage) # N is the number of vaccinated participants with available data for the immunologic endpoint listed Þ Pooled TIV-HD group includes subjects vaccinated with either TIV-HD1 or TIV-HD2 for the A strain comparison |
Fluzone High-Dose Quadrivalent was as immunogenic as Fluzone High-Dose for GMTs and seroconversion rates for the common influenza strains. Fluzone High-Dose Quadrivalent induced a superior immune response, based on a pre-specified superiority criterion, with respect to the additional B strain than the immune response induced by Fluzone High-Dose formulation that did not contain the additional B strain.
Efficacy Of Fluzone High-Dose In Adults 65 Years Of Age And Older
The efficacy of Fluzone High-Dose (trivalent formulation) is relevant to Fluzone High-Dose Quadrivalent since both vaccines are manufactured according to the same process and have overlapping compositions.
Study 2 (NCT01427309) was a multi-center, double-blind, post-licensure efficacy trial conducted in the U.S. and Canada in which adults 65 years of age and older were randomized (1:1) to receive either Fluzone High-Dose or Fluzone. The study was conducted over two influenza seasons (2011-2012 and 2012-2013); 53% of participants enrolled in the first year of the study were re-enrolled and re-randomized in the second year. The per-protocol analysis set for efficacy assessments included 15,892 Fluzone High-Dose recipients and 15,911 Fluzone recipients. The majority (67%) of participants in the per-protocol analysis set for efficacy had one or more high-risk chronic comorbid conditions.
In the per-protocol analysis set, females accounted for 57.2% of participants in the Fluzone High-Dose group and 56.1% of participants in the Fluzone group. In both groups, the median age was 72.2 years (range 65 through 100 years). Overall, most participants in the study were White (95%); approximately 4% of study participants were Black, and approximately 6% reported Hispanic ethnicity.
The primary endpoint of the study was the occurrence of laboratory-confirmed influenza (as determined by culture or polymerase chain reaction) caused by any influenza viral type/subtype in association with influenza-like illness (ILI), defined as the occurrence of at least one of the following respiratory symptoms: sore throat, cough, sputum production, wheezing, or difficulty breathing; concurrent with at least one of the following systemic signs or symptoms: temperature >99.0°F, chills, tiredness, headaches or myalgia. Participants were monitored for the occurrence of a respiratory illness by both active and passive surveillance, starting 2 weeks post-vaccination for approximately 7 months. After an episode of respiratory illness, nasopharyngeal swab samples were collected for analysis; attack rates and vaccine efficacy were calculated (see Table 5).
Table 5: Study 2*: Relative Efficacy Against Laboratory-Confirmed Influenza† Regardless of Similarity to the Vaccine Components, Associated with Influenza-Like Illness‡, Adults 65 Years of Age and Older
| Fluzone High-Dose N§ =15,892 n¶ (%) | Fluzone N§ =15,911 n¶ (%) | Relative Efficacy % (95% CI) |
| Any type/subtype# | 227 (1.43) | 300 (1.89) | 24.2 (9.7; 36.5)Þ |
| Influenza A | 190 (1.20) | 249 (1.56) | 23.6 (7.4; 37.1) |
| A (H1N1) | 8 (0.05) | 9 (0.06) | 11.0 (-159.9; 70.1) |
| A (H3N2) | 171 (1.08) | 222 (1.40) | 22.9 (5.4; 37.2) |
| Influenza Bß | 37 (0.23) | 51 (0.32) | 27.4 (-13.1; 53.8) |
* NCT01427309 † Laboratory-confirmed: culture or polymerase-chain-reaction–confirmed ‡ Occurrence of at least one of the following respiratory symptoms: sore throat, cough, sputum production, wheezing, or difficulty breathing; concurrent with at least one of the following systemic signs or symptoms: temperature >99.0°F, chills, tiredness, headaches or myalgia § N is the number of vaccinated participants in the per-protocol analysis set for efficacy assessments ¶ n is the number of participants with protocol-defined influenza-like illness with laboratory confirmation # Primary endpoint Þ The prespecified statistical superiority criterion for the primary endpoint (lower limit of the 2-sided 95% CI of the vaccine efficacy of Fluzone High-Dose relative to Fluzone >9.1%) was met. ß In the first year of the study the influenza B component of the vaccine and the majority of influenza B cases were of the Victoria lineage; in the second year the influenza B component of the vaccine and the majority of influenza B cases were of the Yamagata lineage |
A secondary endpoint of the study was the occurrence of culture-confirmed influenza caused by viral types/subtypes antigenically similar to those contained in the respective annual vaccine formulations in association with a modified CDC-defined ILI, defined as the occurrence of a temperature >99.0°F (>37.2°C) with cough or sore throat. The efficacy of Fluzone High-Dose relative to Fluzone for this endpoint was 51.1% (95% CI: 16.8; 72.0).
REFERENCES
3. Hannoun C, Megas F, Piercy J. Immunogenicity and protective efficacy of influenza vaccination. Virus Res 2004;103:133-138.
4. Hobson D, Curry RL, Beare AS, Ward-Gardner A. The role of serum haemagglutination-inhibiting antibody in protection against challenge infection with influenza