Pediatric Influenza Armamentarium Bolstered by New Investigational Vaccine

Seqirus IIV4, an investigational quadrivalent inactivated influenza vaccine (IIV4) developed by Seqirus Pty Ltd, Australia, confers immunogenicity that is noninferior to the US-licensed 2015-2016 comparator IIV4, according to a study recently published in Vaccine.¹

“This phase 3, randomized, observer-blinded study [ClinicalTrials.gov identifier: NCT02545543] is the first study to report the immunogenicity and safety of Seqirus’ inactivated quadrivalent influenza vaccine (IIV4) in children aged 5 to 17 years,” said Dr Jane Leong, Head of Asia Pacific Medical Affairs at Seqirus and coauthor of the study in an email interview with Infectious Disease Advisor.

The multicenter trial enrolled 2278 healthy male and female subjects, aged 5 to 17 years, in 32 US medical centers from September 2015 to June 2016. Study participants were randomly assigned to 1 of 2 cohorts — the 5 to 8 years of age cohort and the 9 to 17 years of age cohort — and received either investigational IIV4 (n=1709) or comparator IIV4 (n=569) in a 3:1 ratio. Both vaccines contained the type A (H1N1)-like virus, the type A (H3N2)-like virus, and 2 type B strains (Yamagata and Victoria).

“Seqirus’ IIV4 demonstrated [noninferior immunogenicity] for all 4 strains with a clinically acceptable safety profile when compared to a licensed comparator IIV4,” added Dr Leong.

Noninferiority assessment was performed based on analysis of immunogenicity criteria for noninferiority, the hemagglutination inhibition (HI) geometric mean titer (GMT) ratio and seroconversion rates (SCRs). Postvaccination HI GMTs were similar for both vaccines and across all investigated strains with the exception of the type B/Yamagata strain, which was significantly higher for IIV4 compared to the comparator IIV4 (60.9 and 54.3, respectively). The 2 vaccines also had comparable postvaccination SCRs, which were higher for the type A/H3N2 strain compared with the other tested strains.

Both vaccines were well tolerated by study participants and exhibited comparable safety profiles. The overall safety population consisted of 2252 participants, 63.5% of whom reported at least 1 adverse event (AE), both solicited and unsolicited. Overall, 64.7% of IIV4 participants and 60.2% of comparator IIV4 participants reported at least 1 AE postvaccination. Most participants for both vaccines reported AEs as mild (36.9%) or moderate (20.8%) in intensity, with headache and myalgia the most common solicited systemic AEs in both vaccine groups. Fever rates were slightly higher in the IIV4 group.

Dr Leong explained that “quadrivalent influenza vaccines are particularly valuable during seasons in which both B strain lineages are co-circulating or there is an unexpected shift from one lineage to another.”

“Results from this study support the use of Seqirus’ IIV4 for the prevention of seasonal influenza in children 5 to 17 years of age,” Dr Leong added. She further noted that Seqirus is working on obtaining Food and Drug Administration approval for use of the vaccine in this population.

“In the United States, the vaccine (Afluria®) is currently registered for use in adults aged 18 years and older.”

Reference

Airey J, Albano FR, Sawlwin DC, et al. Immunogenicity and safety of a quadrivalent inactivated influenza virus vaccine compared with a comparator quadrivalent inactivated influenza vaccine in a pediatric population: a phase 3, randomized noninferiority study. Vaccine. 2017; 35(20):2745-2752. doi: 10.1016/j.vaccine.2017.03.028