Viral clearance studies on new and used chromatography resins: Critical review of a large dataset

Viral clearance studies for naïve and maximally cycled chromatographic resins used for cGMP recombinant protein production are reviewed for three products, comprising 10 different chromatographic steps, including affinity, ion exchange, immobilized metal ion affinity, and hydrophobic interaction modes. Thirty-two separate studies were conducted (over 90 runs in total). No consistent reductions in model virus clearance were observed with used resins. The results address the reproducibility of virus clearance studies conducted by different scientists over several years at multiple contract labs. The log reduction values (LRVs) are typically within 0.5 LRVs for new and used resin, but varied as much as 2 LRVs for resins showing no functional deterioration. This relatively large difference is not believed to reflect resin changes, but highlights the challenges encountered in modeling column clearance. Production column performance and cleaning efficacy are demonstrated for these steps by trending mock runs, impurity removal and product recovery. No deterioration in cGMP column performance is seen over the established resin lifetimes, confirming that the resin regeneration and sanitization procedures restore the resins to a suitable initial state without damage. It is proposed that for some chromatography steps, the combination of lab-scale cycling studies confirming consistent performance throughout the resin lifetime and monitoring of cGMP manufacturing preclude the need for virus clearance studies on maximally cycled resin.