Safety of MenB Vaccine Is Accurately Measured With MAT

The monocyte activation test (MAT) can consistently and accurately measure the safety of the meningococcal B vaccine (Bexsero), according to new research. 

To measure the MAT’s ability to effectively evaluate the pyrogenic content in the vaccine, the researchers studied data from 9 sites across 9 countries. In all, 15 test systems for 3 batches of the vaccine were analyzed.

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Compared with a reference lot, each batch of the vaccine was either (A) more, (B) less, or (C) equally active. The activity was measured using relative pyrogen units based on the European Pharmacopoeia (Ph. Eur.) MAT Chapter 2.6.30 Method C: Reference Lot Comparison Test. 

Because the test systems all demonstrated that sample A was the most active in the MAT, the researchers determined that all 15 test systems were consistent. In fact, all but 2 of the test systems were more than 80% accurate. 

While the MAT is a reliable method for measuring the pyrogenic content of the meningococcal B vaccine when carried out as a reference lot comparison test, a couple factors can influence the magnitude of the relative pyrogen unit measured.

Test systems that utilized cells from individual blood donations had greater donor-to-donor variability in sample A compared with sample C.

“There could be donor to donor differences in sensitivity to the vaccine constituents responsible for the higher activity of this batch,” the study authors wrote.

“Overall, the consistency and accuracy of the MAT was remarkable given the range of test systems used by participants, all of which are permitted by the Ph. Eur. General MAT Chapter,” the researchers concluded. “This is important given the limitations of the rabbit pyrogen test for the control of pyrogenicity in general and particularly with products with intrinsic pyrogenicity such as Bexsero.”

—Colleen Murphy

Reference:

Studholme L, Sutherland J, Desai T, et al; Collaborative Study Group. Evaluation of the monocyte activation test for the safety testing of meningococcal B vaccine Bexsero: a collaborative study. Vaccine. 2019;37(29):3761-3769. https://doi.org/10.1016/j.vaccine.2018.05.073.