RUNspike, a complementary virus filter spiking method: a solution to the problem of reduced throughput due to the addition of the virus spike.

The traditional approach to virus filter spiking studies (virus added to the feed solution before the start of filtration) can lead to oversized viral filtration systems because of the non-representative volumetric throughputs (L/m2) that can be seen with the addition of the virus spike. The reduction in throughput is thought to be caused by interactions that take place between the species in the virus stock solution alone, or in conjunction with the species in the drug product. The traditional approach assumes that virus filter log reduction value (LRV) is directly related to volumetric throughput and limits manufacturing scale designs to the volumetric throughput achieved in the spiking study.