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Published on: March 8, 2012
Correlation between mouse potency and in vitro relative potency for human papillomavirus Type 16 virus-like particles
M Shank-Retzlaff1, F Wang, T Morley
1Merck Research Laboratories Department of Bioprocess & Bioanalytical Research, West Point, Pennsylvania, USA. Mary_Retzlaff@merck.com
Abstract:
An in vitro relative potency (IVRP) assay has been developed as an alternative to the mouse potency assay used to release Merck's human papillomavirus (HPV) vaccine, Gardasil, for early phase clinical trials. The mouse potency assay is a classical, in vivo assay, which requires 4-6 weeks to complete and exhibits variability on the order of 40% relative standard deviation (RSD). The IVRP assay is a sandwich-type immunoassay that is used to measure relative antigenicity of the vaccine product. The IVRP assay can be completed in three days, has a variability of approximately 10% RSD and does not require the sacrifice of live animals. Because antigen detection is achieved using H16.V5, a neutralizing monoclonal antibody, which binds to a clinically-relevant epitope, the relative antigenicity measured by the IVRP assay is believed to be a good predictor of in vivo potency. In this study, the relationship between immunogenicity, as measured by the mouse potency assay and antigenicity as measured by the IVRP assay, is demonstrated. Freshly manufactured and aged samples produced using two different manufacturing processes were tested using both methods. The results demonstrate that there is an inverse correlation between the IVRP and mouse potency assays. Additionally, clinical results indicate IVRP is predictive of human immunogenicity. Thus, antigenicity, as defined by the H16.V5 epitope, can be used as a surrogate for immunogenicity and the IVRP assay is suitable for use as the sole potency test for Gardasil samples.
Insights
An in vitro relative potency (IVRP) assay offers a faster, more consistent alternative to the traditional mouse potency assay for human papillomavirus (HPV) vaccine release. This new method accurately predicts vaccine immunogenicity in humans.
Area of Science:
- Vaccinology
- Immunology
- Biotechnology
Background:
- The release of Merck's human papillomavirus (HPV) vaccine, Gardasil, relies on a mouse potency assay.
- This in vivo assay is time-consuming (4-6 weeks) and exhibits high variability (approx. 40% RSD).
- An alternative, faster, and more reliable assay is needed for early-phase clinical trials.
Purpose of the Study:
- To develop and validate an in vitro relative potency (IVRP) assay as an alternative to the mouse potency assay for Gardasil release.
- To assess the correlation between antigenicity measured by the IVRP assay and immunogenicity measured by the mouse potency assay.
- To determine if the IVRP assay can serve as a surrogate for in vivo potency and predict human immunogenicity.
Main Methods:
- Development of a sandwich-type immunoassay (IVRP assay) to measure relative antigenicity using the H16.V5 neutralizing monoclonal antibody.
- Testing of freshly manufactured and aged Gardasil samples produced via two different manufacturing processes using both the IVRP and mouse potency assays.
- Correlation analysis between IVRP assay results (antigenicity) and mouse potency assay results (immunogenicity), alongside clinical data evaluation.
Main Results:
- The IVRP assay can be completed in three days with significantly lower variability (approx. 10% RSD) compared to the mouse assay.
- An inverse correlation was observed between the IVRP and mouse potency assays.
- Clinical data confirmed that the IVRP assay is predictive of human immunogenicity.
Conclusions:
- The IVRP assay, measuring antigenicity via the H16.V5 epitope, is a suitable surrogate for immunogenicity and can predict in vivo potency.
- The IVRP assay is validated as a reliable and efficient sole potency test for Gardasil samples in early-phase clinical trials.
- This in vitro method offers a significant improvement over the traditional animal-based assay, reducing time, cost, and animal use.
