Viral & Transmissible Spongiform Encephalopathy Clearance

Viral clearance studies are an essential part of a manufacturer's program to ensure product safety. Manufacturers of biopharmaceutical products or auxiliary material derived from animal or human tissues are required to demonstrate the ability of their purification and manufacturing processes to inactivate or remove viruses or TSE agents and ensure product safety.

Examples of animal- or human tissue-driven products include:

A database of more than 2,500 studies performed for clients guides our ability to develop, execute, and evaluate the viral/TSE clearance studies that best meet our clients’ needs. From downscale assistance to report generation, we promise a successful study design and execution, and a report that will support your regulatory submission without delay.

Webinar: Choosing the Right Virus for Your Viral Clearance Studies

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Learn more about determining the optimal viruses for your viral clearance studies.

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    • Risk-based assessments – Comprehensive review of a client’s viral safety testing program, production processes and raw material quality in order to minimize required viral clearance and ensure an economic study design
    • Holistic study design – Review of required pretesting, virus spikes, sampling modes, detection methods and assay sensitivities to define the most effective virus clearance study approach
    • Optimized sensitivity – Standard inclusion of large volume plating for all product-relevant samples to improve LRV claims and demonstrate effective and robust virus reduction
    • Regulatory expertise – Alignment of study design and reporting with the development stage of the product and compliance with national and global regulations outlined in US FDA, EMA, ICH and other country-specific regulatory documents
    • Customized service – Extensive experience with multiple product types and purification steps, allowing us to provide support and advice tailored to each product and its requirements, including downscale assistance, execution of process steps and interpretation and troubleshooting of results
    • Industry leadership – Application of best practices as determined by performance of internal studies and as presented in multiple viral safety conferences, symposia, publications and technical reports in order to define the most scientifically sound study design

    Our laboratories in the United States and Europe have the technical and regulatory expertise to ensure viral clearance studies comply with the relevant guidelines in your market (e.g., FDA [USA], EMA [EU], PEI [Germany], MHLW [Japan], MW [Korean Ministry of Health and Welfare], and WHO, including ICH Q5A). Each facility offers dedicated client labs and private client offices to support maximal productivity during on-site visits. These sites have an assortment of fully qualified and validated ÄKTA™ chromatography systems.


    With a focus on partnership, we provide a host of supplemental services to support clients throughout the planning and execution of a successful viral clearance studies program, including chromatography and virus cleaning validation. Other benefits of working with Charles River include:

    • Mycharlesriver℠ secure online client data portal
    • Dedicated project manager
    • The ability to perform process steps without the client needing to be onsite
    • We can accompany clients to agency visits and/or can be present during agency audits
    • On-site client seminars and training

A careful analysis of the manufacturing process to remove or inactivate a wide range of model viruses or TSE agents plays an important role in establishing the safety of biological products. Put our regulatory and technical expertise to the test addressing issues that will ultimately help avoid timeline delays.


Frequently Asked Questions (FAQs) About Viral Clearance Studies

  • What are clearance studies?

    Clearance is a measure of the capacity of the dedicated manufacturing process steps to primarily inactivate or remove viruses and transmissible spongiform encephalopathy (TSE) agents.

    Viral clearance studies involve deliberate spiking of viruses or TSE agents into process intermediates and then demonstrating their inactivation or removal during the subsequent processing steps.

    This is usually done on a scaled-down version – a laboratory version – of the selected process steps. Our Viral Clearance and TSE Clearance Studies technical sheet provides more in-depth information on this topic.

  • What are some examples of viral inactivation methods?

    Examples of viral inactivation methods are:

    • Low pH inactivation is effective against enveloped viruses
    • Solvent/detergent inactivation is effective against enveloped viruses
    • Pasteurization, which inactivates both enveloped and some non-enveloped viruses
    • Terminal dry heat, which inactivates both enveloped and some non-enveloped viruses
    • Irradiation and high-energy light
  • Can viruses be filtered?

    Viruses can be filtered through the process of nanofiltration, which removes viruses according to their size, while permitting flow through of the desired proteins. A model virus of a specific size will represent all viruses of the same or greater size.

  • At what temperature can a virus be inactivated?

    The inactivation of a virus requires temperatures of 60°C and above and is highly dependent on the remaining moisture in the sample and the duration of incubation.