MADRID, Apr 6 (APM) - GlaxoSmithKline is claiming that Spanish media reports about Pfizer’s meningococcal vaccine overstate its efficacy, while Pfizer says the information it gave journalists at the presentation of the vaccine earlier this week is backed up by clinical data.

Following media reports about Pfizer’s meningococcal group B vaccine Trumenba being “more effective” than GSK’s Bexsero, the latter company argued in a statement that Bexsero is the only one of the two jabs whose efficacy has been proven with rea world data.

According to a Friday statement sent by GSK, “the real impact of a vaccine can only be estimated based on efficacy data obtained in real-life scenarios, that means after it has been given to the population as part of vaccination plans”.

GSK’s statement said the comparison between the two vaccines was "inadequate".

Pfizer has responded that its vaccine has been approved recently, adding that real-life evidence will be gathered “as happens with any other vaccine”, once it has been extensively administered to the population.

90% threshold the bone of contention

The information Pfizer provided to the media, which was widely published, said Trumenba protects against over 90% of meningococcal strains present in Spain. In a statement emailed to APM on Friday afternoon, Pfizer said this figure is correct according to the vaccine’s product information as published by the European Medicines Agency (EMA), the assessment report by EMA’s CHMP committee and the latest study on Trumenba published in the Journal of the American Society for Microbiology (mBio).

Based on two collections of invasive NmB isolates, the authors of the study concluded that over 91% of all meningococcal serogroup B isolates expressed sufficient levels of fHBP to be susceptible to bactericidal killing by Trumenba-induced antibodies.

In its report, the CHMP admitted the use of in vitro serum bactericidal assays as a surrogate measure of efficacy because the incidence of MnB in Europe is very low and a clinical efficacy trial would not be possible.

According to GSK’s statement, a systematic vaccination plan in the UK has shown Bexsero’s efficacy against preventable meningococcal group B strains can be as high as 94%.

Bexsero protects against 83% of strains present in the UK, according to a study published in PLoS One. However, data provided by the Spanish National Reference Laboratory show the figure for Spain would be lower, at 69%, according to Pfizer's statement.

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