Safety profile of Infanrix hexa – 17 years of GSK’s passive post-marketing surveillance

DTaP-IPV-HB-Hib vaccine (Hexaxim): an update 10 years after first licensure

INTRODUCTION

Hexaxim® is fully liquid, hexavalent, combination vaccine that provides immunization against diphtheria, tetanus, pertussis (whooping cough), polio, hepatitis B, and invasive diseases caused by Haemophilus influenzae type b. Combination vaccines such as Hexaxim reduce the number of injections needed, improving both vaccination compliance and operational efficiency.

AREAS COVERED

Safety and immunogenicity data were reviewed from >25 clinical trials involving approximately 7200 infants/toddlers, identified using PubMed searches to April 2023. These trials have evaluated a diverse range of primary series and booster schedules, including antibody persistence, co-administration of Hexaxim with other routine pediatric vaccines, and specific populations (born to Tdap-vaccinated women, preterm, and immunocompromised infants). Lastly, post-marketing surveillance and real-world effectiveness data were assessed.

EXPERT OPINION

An extensive program of clinical development prior to licensure demonstrated favorable vaccine safety and good immunogenicity of each antigen, and Hexaxim was first approved for use in 2012. In the 10 years since licensure, Hexaxim has been adopted widely, with more than 180 million doses distributed worldwide. The widespread use of this hexavalent vaccine is a crucial tool in the ongoing and future control of six pediatric infectious diseases globally.

Hexavalent vaccines: What can we learn from head-to-head studies?

BACKGROUND

Three hexavalent vaccines against diphtheria, tetanus, pertussis, poliomyelitis, hepatitis B virus (HBV), and Haemophilus influenzae type b (Hib) are licensed in Europe: Infanrix hexa (DT3aP-HBV-IPV/Hib), Hexyon (DT2aP-HBV-IPV-Hib) and Vaxelis (DT5aP-HBV-IPV-Hib).

METHODS

A systematic literature search was performed in various electronic databases to identify published peer-reviewed head-to-head studies comparing any licensed hexavalent vaccine to another.

RESULTS

Predefined inclusion criteria were met by 12 articles. Individual studies concluded that the 3 hexavalent vaccines have acceptable safety profiles although some significant differences were observed in their reactogenicity profiles. The immunogenicity of DT2aP-HBV-IPV-Hib and DT5aP-HBV-IPV-Hib was non-inferior versus DT3aP-HBV-IPV/Hib. Some differences in immune responses to common antigens were observed, but their clinical relevance was not established. Anti-filamentous hemagglutinin (FHA) from pertussis and anti-polyribosylribitol phosphate (PRP) from Hib antibody concentrations tended to be higher, and anti-HBV and anti-pertussis toxin (PT) from pertussis antibody concentrations lower in DT2aP-HBV-IPV-Hib versus DT3aP-HBV-IPV/Hib vaccinees. Anti-PT and post-primary anti-PRP antibody concentrations tended to be higher, and anti-HBV, anti-FHA, anti-pertactin from pertussis and post-booster anti-PRP antibody concentrations lower in DT5aP-HBV-IPV-Hib versus DT3aP-HBV-IPV/Hib recipients. Slightly lower immune responses towards most vaccine antigens were observed with 2 + 1 versus 3 + 1 schedules post-primary vaccination, suggesting that 2 + 1 schedules should only be considered in countries with very high vaccination coverage.

CONCLUSION

Although the licensed hexavalent vaccines are generally considered similar, analyses of immunogenicity data from head-to-head trials highlighted differences that could be related to differences in composition and formulation. In addition, the demonstrated non-inferiority of the immunogenicity of the more recent vaccines versus DT3aP-HBV-IPV/Hib does not allow a full bridging to similar efficacy, effectiveness and safety. The availability of DT3aP-HBV-IPV/Hib over > 20 years allowed to collect a wealth of data on its long-term immunogenicity, safety and effectiveness in clinical and post-marketing studies, and makes it a key pillar of pediatric immunization.

How were DTP-related adverse events reduced after the introduction of an acellular pertussis vaccine in Chile?

Chile has a passive surveillance system of adverse events following immunization (AEFI) that allows monitoring and evaluating the safety profile of the vaccines administered. Between 2018 and 2019, the National Immunization Program (NIP) changed from a pentavalent whole-cell pertussis vaccine (wP) to a hexavalent (DTaP-IPV-HepB-Hib) acellular pertussis vaccine (aP) for children <2 years.

Hexavalent vaccines in infants: a systematic literature review and meta-analysis of the solicited local and systemic adverse reactions of two hexavalent vaccines

Introduction: The hexavalent vaccine DT3aP-HBV-IPV-Hib (Infanrix hexa, GSK) was first licensed in Europe in 2000. DT2aP-HBV-IPV-Hib (Hexyon/Hexacima/Hexaxim, Sanofi Pasteur), and DT5aP-HBV-IPV-Hib (Vaxelis, MCM Vaccine Company) were licensed in the EU in 2013 and 2016, respectively, based largely on studies demonstrating non-inferiority to DT3aP-HBV-IPV-Hib for immunogenicity and comparable reactogenicity profiles.Methods: We conducted a systematic literature review looking for direct head-to-head trials comparing DT2aP-HBV-IPV-Hib and DT5aP-HBV-IPV-Hib with DT3aP-HBV-IPV-Hib. The incidence of solicited local and systemic reactions following primary series administration of DT3aP-HBV-IPV-Hib or DT2aP-HBV-IPV-Hib were meta-analyzed.Results: A total of 317 unique records were retrieved from the search; nine met the predefined inclusion criteria; seven reported studies comparing DT3aP-HBV-IPV-Hib and DT2aP-HBV-IPV-Hib. Six trials assessing outcomes of the primary vaccination series were identified. Odds ratios and 95% confidence intervals (OR; 95%CI) were computed for DT3aP-HBV-IPV-Hib, using DT2aP-HBV-IPV-Hib as reference, for redness (0.72; 0.63-0.83), pain (0.74; 0.62-0.89), swelling (0.86; 0.74-0.99) at injection site, fever (0.67; 0.54-0.83), persistent crying (0.72; 0.61-0.84), drowsiness (0.82; 0.71-0.94), irritability (0.82; 0.69-0.98), anorexia (0.83; 0.72-0.95), and vomiting (0.96; 0.83-1.11).Conclusion: ORs of analyzed local and systemic solicited adverse reactions after primary vaccination with DT3aP-HBV-IPV-Hib appear to be slightly lower than with DT2aP-HBV-IPV-Hib.