As viruses can arise during the manufacture of biopharmaceuticals, regulatory agencies require “viral clearance” validation studies for each biopharmaceutical prior to approval. For example, Type C Retrovirus-Like Particles (RVLP) are endogenously produced during CHO cell expression. As such, regulatory agencies require proof that downstream process steps can effectively remove or inactivate retrovirus. A model mammalian virus, Xenotropic Murine Leukemia Virus (XMuLV) is typically used to demonstrate RVLP clearance. However, the establishment of RVLP quantification methods has made it possible to…
Viral Clearance
Shaping the Future of Viral Clearance: Analyzing ICH Q5A(R2) and Its Impacts
In October 2022, a new draft of ICH Q5A (R2) was released, the first such update in more than 20 years. This draft revision was necessary to reflect current scientific knowledge and biotechnology advances such as new product types that are amenable to viral clearance and alternative virus clearance validation strategies. In this report, we delve into the evolving landscape of viral clearance practices, focusing on the implementation of continuous manufacturing, advancements in study design, and the implications for cell…
Using CHO-Endogenous RVLPs for Retroviral Clearance Studies
Early evidence of budding C-type particles from Chinese hamster ovary (CHO) cells was documented in the 1970s and 1980s (1, 2). In the early 1990s, scientists from Genentech began to characterize these “retrovirus-like particles” (RVLPs) from CHO cells (3). Although proven to be noninfectious (1, 2), the endogenous particles caused regulators to require a demonstration of retrovirus clearance before clinical trials or market approval authorization (4). To accomplish that, the biopharmaceutical industry adopted the use of xenotropic murine leukemia virus…
Viral Safety for Biotechnology Products, Including Viral Vectors: ICH Q5A Revision 2 Brings Updated and More Comprehensive Guidance
The International Council for Harmonisation of Technical Requirements for Pharmaceuticals for Human Use (ICH) provides guidance on the testing and evaluation of viral safety of biotechnological products derived from characterized cell lines of human or animal origin through its harmonized guideline ICH Q5A (1). The latest revision, released for consultation in October 2022, maintains the key principles of previous versions while introducing key changes in response to important advances in the field. Those advances are covered in new sections that…
Introduction: Viral Clearance and Inactivation in Downstream Processing
Viral safety in the biopharmaceutical industry is both an upstream-production and downstream-processing concern. Companies must take a multipronged approach using orthogonal methods that are validated to prevent viral contamination or to remove it from biologic drug products. On the upstream side, the focus is on prevention through risk assessment and mitigation. That begins with environmental control of facilities and includes both careful selection of raw materials and cell lines and preparatory filtration of culture media components. In downstream processing of…
Triton X-100 Elimination: The Road Ahead for Viral Inactivation
The nonionic surfactant Triton X-100 (C14H22O(C2H4O)n) is a key chemical used in ensuring the viral safety of biological medicinal products. Two pharmaceutical sectors share an extensive historical background with it: biopharmaceuticals and plasma-derived products, for which it is used to inactivate lipid-enveloped viruses. Recently, environmental regulations in the European Union have encouraged or mandated a phase-out of this surfactant (1). The goal of the ruling is to protect aquatic ecosystems from potential Triton X-100 degradation products that can function as…
Worst-Case Conditions for Viral Clearance
As described in ICH Q5A on virus safety of biotechnological products (1) and the European guideline on virus safety of biotechnological products, EMEA 398498 (2), viral clearance studies are mandated as part of the viral safety evaluation of products derived from human or other mammalian cell lines. When acceptable ranges of process parameters are known, both guidelines recommend that scale-down models be evaluated under worst-case conditions for viral clearance. The BioPhorum Development Group’s viral clearance workstream performed a benchmarking survey…
Hollow-Fiber Nanofiltration for Robust Viral Clearance of Non-MAb Biologics
Monoclonal antibody (MAb) and other therapeutic biologics produced by mammalian cells have the potential to introduce endogenous retroviruses and can be infected with adventitious viruses through raw materials or other parts of the biomanufacturing process (1–3). Based on regulatory guidelines, products derived from mammalian cells must contain less than one virus particle per million doses, which requires purification processes to demonstrate virus removal capabilities of about 12–18 log10 clearance of endogenous retroviruses and 6 log10 clearance for adventitious viruses (4).…
Comprehensive Virus Clearance Evaluation Using Microscale Membrane Adsorbers
Membrane adsorbers can be a simple and effective choice for anion-exchange (AEX) purification of biopharmaceuticals. However, as Sherri Dolan (global technology consultant for virus clearance at Sartorius) explained during a May 2022 presentation, biomanufacturers generally do not leverage their membranes’ full loading capacities. Doing so could improve process economics and decrease costs for several downstream applications. Dolan’s Presentation Membrane adsorbers are ideal for flow-through AEX applications (e.g., secondary purification and polishing) because they can be used at high flow rates…
The Impact of Protein Stability on Virus Filtration
Filtration of protein-based biologics is essential for minimizing viral contamination and ensuring product safety and high quality. The tendency of therapeutic monoclonal antibodies (MAbs) and recombinant proteins to aggregate under a number of conditions can complicate selection of a virus filter. An increasing demand for high concentration formulations creates additional challenges. When performing filterability studies and to ensure meaningful virus filter evaluations, downstream process scientists must address factors that can lead to aggregation. This special report on virus filtration by…