P694 Validation of two commercial assays for therapeutic drug monitoring of adalimumab biosimilars
R. Berghmans1, J. Naudts2, B. Ferkinghoff3, H. Gören3, M.L. Henke3, A. Lennerz4, T. Van Stappen4
1apDia bvba, Research & Development, Turnhout, Belgium, 2apDia bvba, Marketing, Turnhout, Belgium, 3R-Biopharm AG, QM/RA Technical Validation, Darmstadt, Germany, 4R-Biopharm AG, Gastroenterology, Darmstadt, Germany
Background
Therapeutic drug monitoring of adalimumab (ADM) is increasingly used to optimise the management of patients with inflammatory bowel disease. The recent settlements with Abbvie concerning Humira®, paved the way for biosimilar drugs to enter the European market. In this study, we aimed to validate two commercial assays, the RIDASCREEN® ADM Monitoring (ELISA; also known as the apDia Adalimumab ELISA) and the RIDA®QUICK ADM Monitoring (rapid assay), which were developed and validated using the originator drug, for the quantification of two ADM biosimilars, AMGEVITA® and Imraldi®.
Methods
To validate the RIDASCREEN® ADM Monitoring, accuracy and recovery were determined by diluting AMGEVITA® and Imraldi® to varying concentrations within the clinical measuring range and in comparison with Humira®. The specification of accuracy is met when the deviation of the measured ADM biosimilar value is within ±15% of the theoretical value. For the recovery, the deviation of the measured ADM biosimilar value has to be within ± 15% of the Humira® value. To validate the RIDA®QUICK ADM Monitoring for the quantification of AMGEVITA® and Imraldi®, the recovery and linearity was determined. The recovery was determined by spiking three samples containing a low concentration of ADM biosimilar with varying concentrations of ADM biosimilar. The rapid assay complies with the requirements of recovery, if the observed value of ADM biosimilar is within ± 20% of the expected value of ADM biosimilar. The linearity was performed on the basis of NCCLS-guideline EP6-A; a sample with high concentration of ADM biosimilar was diluted 1:1 to 1:38.4. All samples were measured in the ELISA and rapid assay following manufacturer’s instructions.
Results
In the RIDASCREEN® ADM Monitoring, the mean deviation of the measured AMGEVITA® and Imraldi® value vs. the theoretical value was −6.6% and 2.1%, respectively. Recovery of spiked AMGEVITA® and Imraldi® samples in serum revealed a maximum absolute deviation of 12.9% and 14.8% vs. Humira®. In the RIDA®QUICK ADM Monitoring, the mean recovery of three serum samples spiked with varying concentration of AMGEVITA® and Imraldi® ranged from 91% to 115%, and 95% to 101%, respectively. Linearity was shown for both AMGEVITA® and Imraldi®.
Conclusion
We successfully validated the biosimilars AMGEVITA® and Imraldi® in the RIDASCREEN® ADM Monitoring and RIDA®QUICK ADM Monitoring. These results encourage therapeutic drug monitoring of ADM biosimilars in routine clinical practice.