Genetic Engineering & Biotechnology News

JUN15 2018

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GENengnews.com | Genetic Engineering & Biotechnology News | JUNE 15, 2018 | 15 matrix, using samples of individual human donor serum from patients with metastatic breast cancer. Eight different human do- nor samples were analyzed, of which seven showed selectivity for the trastuzumab tar- get within breast cancer serum with recov- ery of the spiked trastuzumab analyte at the LLOQ (Figure 2). The final patient sample showed previous exposure to trastuzumab. Consequently, this patient's sample lacked selectivity. This selectivity assessment meets the regu- latory target acceptance criteria for the assay, where 80% of samples show selectivity with sufficient bias and precision from the nomi- nal values, and demonstrates the functional capability of the Affimer reagent, which re- mained highly selective for the target with no matrix effect across the range of individual patient serum samples. Stability at Room Temperature Benchtop stability of the Affimer as a coating for the ELISA assay was assessed by storing a vial of Affimer reagent at ambient room temperature for 24 ± 4 hours prior to its use to coat ELISA plates. Comparison of the standard curve responses from both the control and Affimer reagent stored at ambi- ent temperature were highly comparable, re- vealing theoretical concentrations for LQC and HQC samples with accuracy and preci- sion well within the target specification for stability, of ±20% bias and ≤20% precision. Lot-to-Lot Performance A major issue with the use of anti-idio- typic reagents in bioanalysis assays is poor lot-to-lot reproducibility. Resolving this is- sue and maintaining assay performance can require extensive standardization between different lots. As Affimer reagents are simple to produce, the variability of recombinant protein between different production lots is minimized. Four separate lots of the anti-trastuzumab Affimer reagent were analyzed concurrently by comparing the reproducibility of their calibration curves for accuracy and precision (Figure 3). A high level of consistency across all four lots was demonstrated, with the es- timated concentrations generated from each respective standard curve yielding an inter- assay accuracy and precision well within the target acceptance criteria for regulatory bio- analysis assay reagents. Conclusion For this study, Covance validated the use of Affimer reagents as part of a high- performance bioanalytical assay according to regulatory standards. Affimer reagents demonstrated excellent target sensitivity, stability, and a broader dynamic assay range compared to the current antibody-based as- say, with no detectable matrix effect. These advantages could lead to assay benefits including improved inter-assay ac- curacy and reproducibility between patient samples, as well as a reduction in the num- ber of required dilutions and the number of sample repeats. Additionally, reducing the variability found in critical assay reagents through the adoption of reproducible sub- stances, such as Affimer binders, could of- fer efficiency savings for drug development processes. A key feature of Affimer technology is the rapid development of highly specific bind- ers without the need for affinity maturation (within just three months), allowing further reductions in project timelines and cost savings to many development programs. Taken together, these data demonstrate the validity of Affimer binders as alternative, or complementary, critical reagents to tradi- tional antibodies for regulated pharmacoki- netic assays of biotherapeutics. Finally, the results presented here highlight the scope of Affimer reagents in a regulated bioanalysis setting. Ultrasensitive | Broad Range | High Specifi city Optimize and Monitor Product Integrity with Ultrasensitive Solutions Contamination monitoring is critical in bioprocessing. Protein contamination can decrease the effi cacy of a biologic and increase its immunogenicity. Early detection of contaminants mitigates risks and reduces cost. Enzo offers ultrasensitive solutions for quantitative detection of Protein A, Host Cell Proteins, and Protein Aggregates to ensure a fl awless biotherapeutic. Protein A ELISA Kit Detect natural and recombinant Protein A variants with up to 100% recovery . PROTEOSTAT ® Protein Aggregation Assay Detect visible to subvisible aggregated proteins in solution. Host Cell Protein ELISA Kits Quantify host cell protein contamination in CHO and E. coli derived biologics. scientists enabling scientists ª www.enzolifesciences.com/bioprocess For Research Use Only Not for Use in Diagnostic Procedures © 2018 Enzo Life Sciences Accelerate Bioprocess Development Quantify Protein Impurities Drug Discovery Amanda Nicholl (amanda.nicholl@avacta. com) is senior assay development scientist at Avacta. Website: www.avacta.com.

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