Characterization of recombinant Factor C enzyme critical quality attributes

Authors:: Poster Author(s)

Rachel Carley, FDA/CDER (Student); Xin Bush, Jackie Cullinan, Abigail Workmeister, Opeyemi Ajayi, Patricia Hughes, Scott Lute, Sarah Johnson, Cyrus Agarabi, Talia Faison FDA/CDER (Mentor)

Center:: Contributing Office

Center for Drug Evaluation and Research

Abstract

Poster Abstract

Current regulations for biological product manufacturing require testing for sterility, testing for pyrogenic substances, testing to ensure sterile and pyrogen free drug product batch, and in-process microbial tests for manufacturing process monitoring. Compendial methods of bacterial endotoxin testing utilize limulus amebocyte lysate (LAL), which is derived from horseshoe crabs. Along with sustainability concerns, LAL reagent has variability and interference from the Factor G cascade. Recombinant protein-based alternatives – recombinant Factor C (rFC) –entered the market with promising specificity, reduced variability, and sustainability of the horseshoe crab populations. However, the US Patent for the recombinant Factor C protein expired in 2017 which allowed for new vendors to enter the market with rFC derived from various species sources. Unlike traditional LAL kits for endotoxin detection, rFC manufacturing is not regulated by the FDA. To date, there are no studies that assess the rFC protein of the commercial endotoxin testing kits for lot-to-lot variability of key attributes, such as post-translation modifications or overall stability. The impacts of potential differences in critical attributes of endotoxin detection assay performance are unknown. This project aims to compare the rFC protein from commercially available kits for attributes such as thermostability, molecular size, or post-translation modifications. These experiments will allow for a better understanding of the differences between the rFC protein derived from various species, and potential impact to assay quality and performance in biologic testing.