Viral Clearance

Drugs manufactured from biological products have a potential, limited risk of viral or prion contaminations. Viral Clearance studies assess the robustness of the purification process against adventitious agent contaminations, contributing to the safety of biological drugs.


Viral Clearance studies are a critical preventative measure to ensure the security of biological products. Accidental viral contaminations can unfortunately happen during the manufacturing process. The process must comprise manufacturing steps which reduces an accidental contamination of the final products to an acceptable level for the safety of the patient.
By performing your viral clearance testing at Texcell, you will be able to check whether your process inactivates or removes viruses and avoid potential viral contamination.

“A big thank you for your reactivity and your help on this study. With these elements, we were able to make a convincing response to our regulatory authority. Thank you for your suggestions; we have integrated them into our global production strategy.

Chief Technology Officer, Biopharmaceutical company

For more than 20 years, the Texcell group laboratories, in Europe, the USA, and Asia have executed a combined total of over 10,000 viral clearance studies. Texcell’s experienced scientific staff can offer support, guidance, and consultation services for viral clearance study design, selection of virus panel, and regulatory compliance.
Texcell also provides investigational viral clearance studies “for information only (FIO)”. We tailor them to be quick, cost conscious, and give the most critical information need to design a robust GLP Viral Clearance testing.


Texcell can help you for:
• Maximizing effective Viral Clearance from your manufacturing platform to inactivate or remove viruses
• Performing risk assessments for Viral Clearance performance in advance of parameter setting for process validation
• Collaborating on experiment planning to get the most from FIO studies
• Designing Viral Clearance studies for early and late phase regulatory submissions
• Preparing virus safety assessments for your regulatory submission documents
• Being an extension of your process development team in meetings with your CMC project team or your CMC regulatory team
• Designing Viral Clearance experiments for novel manufacturing processes

The Viral Clearance products experience includes, but is not limited too:
• Monoclonal antibodies
• Recombinant proteins
• Gene therapy products
• Cell therapy products
• Ortho biologics
• Tissues, bone, and collagen
• Blood products
• Nanoparticles
• Vaccines

Investigational viral clearance, Texcell is not limited to manufacturing process

We define investigational Viral Clearance studies as For Information Only or “FIO”, and tailor them to be quick, cost conscious, and give the most critical information needed to design a robust GLP Viral Clearance.
Thanks to FIO viral clearance, Texcell can work with a wide range of customers such as:
• Household appliance companies (refrigerator, ironing facilities…)
• Air conditioning companies
• Car manufacturer (for air filter)
Texcell performed for these companies, studies to check a potential effect that their products could have on various viruses, including the Sars-Cov-2.
Our FIO viral clearances will allow you to communicate the ability of your products to inactivate or remove any potential viral contamination.

Texcell is one of the rare companies able to produce routinely high-titer solutions (>109 TCID50/ml) of most if not all of the viruses for clearance studies. Virus can be produced “highly purified” to avoid membrane clogging during nanofiltration studies.

Here are the most common viruses used for viral clearance studies. Please enquire should you not find your virus of choice in the table below. We most certainly have it in our collections.
Tableau de virus à inclure dans les devis


Name Porcine ParvoVirus Reovirus type 3 Murine Leukemia Virus (xMLV) Bovine viral diarrhea virus Pseudorabies virus (Aujeszky)
Family Parvoviridae Reoviridae Retroviridae Flaviviridae Herpesviridae
Genus Parvovirus Orthoreovirus Oncovirus Pestivirus Varicellovirinae
Origin / Host Porcine Human Murine Bovine Porcine
Genome single strand DNA dble strand RNA single strand RNA single strand RNA dble strand DNA
Envelop Naked Naked Enveloped Enveloped Enveloped
Size 18 – 26 nm 60 – 80 nm 80 – 100 nm 45 – 55 nm 150 – 200 nm


Name Adenovirus type 5 Encephalomyo-carditis virus Parainfluenza virus type 3 Human Immuno-deficiency virus 1 Minute Virus of Mice
Family Adenoviridae Picornaviridae Paramyxoviridae Retroviridae Parvoviridae
Genius Adenovirus Cardiovirus Respirovirus Lentivirus Parvovirus
Origin Human Murine Human Human Murine
Genome dble strand DNA single strand RNA single strand RNA single strand RNA single strand DNA
Envelope Naked Naked Enveloped Enveloped Naked
Size 70 – 90 nm 28 – 30 nm 100 – 300 nm 80 – 100 nm 18 – 26 nm


Virus H1N1 HAV Polio SV40 TGEV
Name Influenza A virus Hepatitis A virus Polio virus (Sabin) Simian virus 40 Transmissible gastroenteritis virus
Family Orthomyxoviridae Picornaviridae Picornaviridae Poliomaviridae Coronaviridae
Genius Influenzavirus Hepatovirus Enterovirus Poliomaavirus Coronavirus
Origin Human Human Human Simian Porcine
Genome single strand RNA single strand RNA single strand RNA dble strand DNA single strand RNA
Envelope Enveloped Naked Naked Naked Naked
Size 100 – 120 nm 28 – 30 nm 28 – 30 nm 45 – 100 nm 100 – 120 nm

We offer three levels of service for viral clearance studies.
For all levels of service, the Sponsor provides all necessary reagents (including columns and filters) to reproduce the manufacturing steps on a downed scale. Texcell team provides standard laboratory equipment (including HPLC), the selected virus panel, performs virus spiking of the starting material, and all related assays for quantitation of virus.

Level III: Premium Service

The scaled-down manufacturing process is tech transferred to Texcell. Texcell personnel execute the entire study at the Texcell laboratory.

Level II: Collaborative Service

Texcell personnel assist Sponsor in execution of the scaled-down manufacturing process at the Texcell laboratory.

Level I: Classic services

Sponsor executes the scaled-down manufacturing process at the Texcell laboratory. Texcell will be in charge of the virus spiking and the titrations

Prions (PrPres, PrPsc, PrPtse) are non-conventional transmissible agents (NCTAs) that have become of major concern to pharmaceutical companies processing bovine or human material since the emergence of new variant Creutzfeld-Jacob disease (vCJD).
Prion investigation studies may be required by the regulatory agencies in order to:

• demonstrate that a cleaning procedure between each production batch is able to destroy prion proteins in the manufacturing equipment.
• investigate the removal of prions during the purification of biological products (i.e., blood fractionation products, bovine extracts, etc.)

The overall level of prion reduction can be determined by deliberately adding (“spiking”) significant amounts of prion to the crude material (or to a model of the manufacturing vessels) and by demonstrating its removal or inactivation during the subsequent steps. Our highly trained staff perform these spiking experiments on scaled-down processing steps in our biosafety level 3 security laboratory.
One main strain is available for the studies, 263K (adapted to hamster), spike preparations and titration methods are also available. Please ask us to help you choose the most relevant parameters for your prion investigation study. We will advise you on the basis of the latest technical and regulatory constraints.