The shake-test for adjuvanted vaccines: A manufacturer's perspective.

Adequate protection of adjuvanted vaccines against accidental freezing is of utmost importance to prevent loss of potency of the Drug Product, and in turn ensure adequate efficacy and safety when injected into patients. In this lessons learned we present two cases, at large- and small-scale manufacturing level, where a loss of potency was observed for an adjuvanted vaccine. By successful application of a shake-test protocol this loss of potency was traced back to atypical transport conditions, leading to accidental freezing of multiple drug product syringes. Controlled experiments show a consistent trend indicating faster settling with an increasing numbers of freeze-thaw cycles. Additionally, we observe an apparent inversely proportional relationship between the freezing speed and the settling rate. The observations further suggest that severe freeze-thaw damage, by for example slow freezing and/or multiple freeze-thaw cycles, can lead to reduced turbidity of the drug product right after resuspension, providing a clear signature of severe freeze-thaw damage. Finally, we show that inspection of the sedimentation layer thickness may provide semi-quantitative information on the severity of freeze-thaw damage. The cases presented in this lessons learned support the effectiveness of a shake test in a manufacturing setting as an additional tool to understand and investigate potential freezing impact during root cause investigations.