Virus Inactivation/Removal & Prion Removal
Viral inactivation and prion removal constitute the primary means by which CSL Behring ensures the quality and safety of its products during the manufacturing process. CSL Behring operates three state-of-the-art manufacturing sites in Marburg, Germany; Bern, Switzerland; and Kankakee, Illinois, United States. CSL Ltd. also operates a state-of-the-art fractionation facility in Melbourne, Australia. All sites are operated in accordance with international quality and safety standards.
We integrate virus inactivation and removal procedures as well as prion removal procedures in the manufacturing process of plasma-derived products to produce safe, effective products. CSL Behring routinely tests these procedures to ensure consistent inactivation and removal of known viruses and prions. The company also tests the products to make sure the active ingredients are not harmed or changed by the inactivation and removal procedures.
During manufacturing the plasma undergoes processes that destroy viral structure. These virus inactivation processes include:
- Low pH treatment
- Solvent/detergent treatment
- Sodium thiocyanate treatment
Specific methods such as virus filtration are integrated in the manufacturing process of some plasma-derived products to remove viruses. CSL Behring was the first biopharmaceutical company to develop and utilize virus filtration. During this process, protein solutions are filtered through membranes with very small pore sizes (typically 15-40 nanometers).
In addition to removing viruses, our manufacturing processes also remove prions through:
Pasteurization is the process of using heat treatment to inactivate a wide range of viruses with differing physiochemical properties. Both enveloped and non-enveloped viruses are inactivated through pasteurization. During this process, stabilizers are used to protect the fragile proteins, but are subsequently removed.
In 1979, CSL Behring (at that time Behringwerke) introduced pasteurization to inactivate pathogens. CSL Behring was the first company to use heat treatment in aqueous stabilized solution at 60°C for 10 hours of labile factors (e.g. factor VIII).
Low pH Treatment (Acidic pH Inactivation)
Some viruses, when exposed to a low pH, will break down spontaneously. Similar to pasteurization, this technique for viral inactivation is useful if the target protein is more resistant to low pHs than the viral impurity. This technique is effective against enveloped viruses.
Solvent/Detergent (S/D) Viral Inactivation
S/D treatments effectively inactivate enveloped viruses by destroying the lipid envelope. The detergents used in this method interrupt the interactions between the molecules in the virus's lipid coating. Most enveloped viruses cannot live without their lipid coating, so they die when exposed to detergents. This process does not denature proteins, because the detergents only affect lipids and lipid derivatives.
Sodium Thiocyanate Treatment
Sodium thiocyanate, a chemical, is used in the purification of the clotting factors FVIII and FIX. It has been shown to inactivate certain viruses.
Virus elimination or virus filtration (nanofiltration) removes viruses by size exclusion. In particular, filters with a defined small pore size remove viruses with a diameter larger than the pore size. The main advantage of this process is that both enveloped and non-enveloped viruses can be removed without denaturing plasma proteins or affecting the quality of the derived products.
CSL Behring was the first biopharmaceutical company to develop and utilize nanofiltration in our Bern, Switzerland facility. During our process, protein solutions are filtered through membranes with very small pore sizes (typically 15-40 nanometers).