Achieving high mass-throughput of therapeutic proteins through parvovirus retentive filters.

Parvovirus retentive filters that assure removal of viruses and virus-like particles during the production of therapeutic proteins significantly contribute to total manufacturing costs. Operational approaches that can increase throughput and reduce filtration area would result in a significant cost savings. A combination of methods was used to achieve high throughputs of an antibody or therapeutic protein solution through three parvovirus retentive filters. These methods included evaluation of diatomaceous earth or size-based prefilters, the addition of additives, and the optimization of protein concentration, temperature, buffer composition, and solution pH. An optimum temperature of 35°C was found for maximizing throughput through the Virosart CPV and Viresolve Pro filters. Mass-throughput values of 7.3, 26.4, and 76.2 kg/m(2) were achieved through the Asahi Planova 20N, Virosart CPV, and Viresolve Pro filters, respectively, in 4 h of processing. Mass-throughput values of 73, 137, and 192 kg/m(2) were achieved through a Millipore Viresolve Pro filter in 4.0, 8.8, and 22.1 h of processing, respectively, during a single experiment. However, large-scale parvovirus filtration operations are typically controlled to limit volumetric throughput to below the level achieved during small-scale virus spiking experiments. The virus spike may cause significant filter plugging, limiting throughput. Therefore newer parvovirus filter spiking strategies should be adopted that may lead to more representative viral clearance data and higher utilization of large-scale filter capacity.