LJUBLJANA, SLOVENIA – under the agency’s Breakthrough Therapy designation.
Dr. Jason D. Maguire
Breakthrough Therapy status is reserved for accelerated review of therapies considered to show substantial preliminary promise of effectively targeting a major unmet medical need.
The unmet need here is that there is no meningococcal group B vaccine approved for use in children under age 10 years. Yet infants and children under 5 years of age are at greatest risk of invasive meningococcal B disease, with reported case fatality rates of 8%-9%, Jason D. Maguire, MD, noted at the annual meeting of the European Society for Paediatric Infectious Diseases.
Trumenba has been approved in the United States for patients aged 10-25 years and in the European Union for individuals aged 10 years or older.
Dr. Maguire, of Pfizer’s vaccine clinical research and development program, presented the results of the two phase 2 randomized safety and immunogenicity trials conducted in patients aged 1- 9 years that the company has submitted to the FDA in support of the expanded indication. One study was carried out in 352 1-year-old toddlers, the other in 400 children aged 2-9 years, whose mean age was 4 years. The studies were carried out in Australia, Finland, Poland, and the Czech Republic.
In a pooled analysis of the vaccine’s immunogenicity when administered in a three-dose schedule of 120 mcg at 0, 2, and 6 months to 193 toddlers and 274 of the children aged 2-9 years, robust bactericidal antibody responses were seen against the four major Neisseria meningitidis group B strains that cause invasive disease. In fact, at least a fourfold rise in titers from baseline to 1 month after dose three was documented in the same high proportion of 1- to 9-year-olds as previously seen in the phase 3 trials that led to vaccine licensure in adolescents and young adults.
“These results support that the use of Trumenba, when given to children ages 1 to less than 10 years at the same dose and schedule that is currently approved in adolescents and young adults, can afford a high degree of protective antibody responses that correlate with immunity in this population,” Dr. Maguire said.
The safety and tolerability analysis included all 752 children in the two phase 2 studies, including the 110 toddlers randomized to three 60-mcg doses of the vaccine, although it has subsequently become clear that 120 mcg is the dose that provides the best immunogenicity with an acceptable safety profile, according to the physician.
Across the age groups, local reactions, including redness and swelling, were more common in Trumenba recipients than in controls who received hepatitis A vaccine and saline injections. So were systemic adverse events. Fever – a systemic event of particular interest to parents and clinicians – occurred in 37% of toddlers after vaccination, compared with 25% of 2- to 9-year-olds and 10%-12% of controls. Of note, prophylactic antipyretics weren’t allowed in the study.
“There’s somewhat of an inverse relationship between age and temperature. So as we go down in age, the rate of fever rises. But after each subsequent dose, regardless of age, there’s a reduction in the incidence of fever,” Dr. Maguire observed.
Most fevers were less than 39.0° C. Only 3 of 752 (less than 1%) patients experienced fever in excess of 40.0° C.
Two children withdrew from the study after developing hip synovitis, which was transient. Another withdrew because of prolonged irritability, fatigue, and decreased appetite.
“Although Trumenba had an acceptable safety and tolerability profile in 1- to 9-year-olds, this analysis wasn’t powered enough to detect uncommon adverse events, so we’ll continue to monitor safety for things like synovitis,” he said.
In 10- to 25-year-olds, the meningococcal vaccine can be given concomitantly with other vaccines without interference. There are plans to study concurrent vaccination with MMR and pneumococcal vaccines in 1- to 9-year-olds as well, according to Dr. Maguire.
Pfizer also now is planning clinical trials of the vaccine in infants, another important group currently unprotected against meningococcal group B disease, he added.
Dr. Maguire is an employee of Pfizer, who funded the studies.