Validation of Virus Removal

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Validation of Virus Removal

• Keith O.Webber, Ph.D.

Deputy Director, Div. of Monoclonal
Antibodies OTRR/CBER/FDA PDA/FDA
Meeting September 26, 2000
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SCOPE - Products

• Specified Biologics
• Monoclonal Antibodies
• rDNA-derived products
• Traditional Biologics
• Some Blood-products
• Some Vaccines

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SCOPE - Methods

• Column Chromatography
• Nano-Filtration (Viral Filtration)
• Other Methods
• Precipitation
• Centrifugation

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Example
Production Fermentor
Protein A affinity chromatography
Anion Exchange Chromatography
Virus filtration
Gel Filtration
Formulation and Fill
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GENERALITIES

• Validation conditions must be representative of
  the actual manufacturing process.
• Validation should use virus-spiking studies.
• Viral clearance studies should not be done in the
  production facility.
• Validations should be done in duplicate.

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SCALE-DOWN

• Scale Down
• Allows validation to be performed in testing labs
• Maintains high titers of the spiking virus
• Must be done appropriately

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CHROMATOGRAPHY

• Parameters that should be representative of
  commercial-scale manufacturing
• CHROMATOGRAPHY MEDIUM
• COLUMN BED HEIGHT
• LINEAR FLOW RATE
• BUFFER COMPONENTS AND CONCENTRATIONS
• pH
• TEMPERATURE
• PRODUCT LOAD

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CHROMATOGRAPHY

• and
• the chromatographic profile and product
  recovery of the scale-down process should be
  comparable to that of the manufacturing process.

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FILTRATION

• Parameters that should be representative of
  commercial-scale manufacturing
• VISCOSITY
• VOLUME PER cm2 OF FILTER AREA
• IONIC STRENGTH
• TEMPERATURE
• pH
• PROTEIN COMPOSITION CONCENTRATION

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FILTRATION

• and
• the product recovery of the scale-down process
  should be comparable to that of the manufacturing
  process.

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CHOOSING VIRUSES

• The aims of viral validation studies are
• to provide evidence that the production process
  will effectively remove viruses which are either
  known to contaminate the starting materials, or
  which could conceivably do so, and
• to provide indirect evidence that the production
  process might remove novel or unpredictable virus
  contamination.

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CHOOSING VIRUSES

• The clearance validation should include
• relevant viruses that may be anticipated to occur
  in the system
• specific model viruses that are physically and
  chemically similar to relevant viruses
• non-specific model viruses that represent the
  extremes of virus properties

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CHOOSING VIRUSES

• Examples of model viruses
• Retrovirus X-MuLV
• Small non-enveloped virus SV40, parvovirus,
  polio virus 1
• Medium to large enveloped RNA virus
  Parainfluenza, Sindbis virus
• Medium to large DNA virus HSV-1, pseudorabies
  virus

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PRECAUTIONS

• Avoid aggregation of spiking virus
• Use small volumes of spiking virus in order to
  retain the sample composition.
• Assess the potential for assay interference by
  the product or buffers.
• Use control assays in parallel to assess the loss
  of infectivity due to dilution, concentration,
  filtration, or storage.
• Include controls to demonstrate the effect of
  procedures used solely to prepare the sample for
  assay.

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General Procedure

• Titer Sample Load
• Take Hold Control sample

Add high Titer Spike to Sample Load

• Titer Hold Control
• Titer Column Flowthrough
• Titer Eluate Sample

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Virus Assay Methodology

• Infectivity is the standard method for clearance
  studies.
• PCR assays and Polymerase Enhanced Reverse
  Transcriptase assays are being developed.

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Evaluation of Results

• Clearance factors from sequential orthogonal
  processes may be combined to give a Cumulative
  Clearance Factor
• Orthogonal processes are those that clear virus
  by independent modes of action (e.g., Anion
  Exchange chromatography and Cation-Exchange
  chromatography)

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Evaluation of Results

• Beware of including both
• a low-pH treatment step and
• a chromatography step that uses elution at a low
  pH
• in the Cumulative Clearance Factor.

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Evaluation of Results

• The Cumulative Clearance Factor must be
  substantially greater than the estimated number
  of virus particles in a volume of the starting
  material required to produce a human dose of the
  drug.

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Evaluation of Results

• The number of virions per mL of starting material
  should generally be estimated by Transmission
  Electron Microscopy.
• One dose of product is generally considered to
  be the total regimen of drug.
• e.g., 1 mg/week x 4 weeks 4 mg dose

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Example
Product
Homologous Product
Protein A affinity chromatography
Anion Exchange Chromatography
Virus filtration
Gel Filtration
Formulation and Fill
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Generic and Modular Validation

• A generic validation study demonstrates virus
  removal or inactivation by a process using a
  model product and allows the use of that process
  with an homologous product without the need to
  revalidate.

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Generic and Modular Validation

• Generic viral clearance validation is applicable
  to situations when the purification process of a
  product is the same as a process that has already
  been validated for an homologous product.

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Chromatography

• The two processes must have the same
• -chromatography medium,
• -column geometry,
• -equilibration buffers,
• -load composition concentration,
• -elution buffers,
• -elution parameters,
• -wash procedure.

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Virus Filtration

• The two processes must have the same
• type of virus filter
• solution characteristics
• VOLUME PER cm2 OF FILTER AREA
• IONIC STRENGTH
• TEMPERATURE
• pH
• PROTEIN COMPOSITION CONCENTRATION

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Generic and Modular Validation

• Example of Homologous Products
• Monoclonal Antibodies of the same species, class,
  and subclass and derived from the same source
  (e.g., ascites, tissue culture, etc.) and cell
  substrate.

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Generic and Modular Validation

• NOTE
• GENERIC VALIDATIONS ARE NOT APPLICABLE TO
  HUMAN-DERIVED PRODUCTS OR PRODUCTS THAT MAY BE
  CONTAMINATED WITH HUMAN PATHOGENS.

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Post-Approval Changes

• Whenever a change is made in the production or
  purification process, the effect of that change
  on the viral clearance should be considered and
  the system re-validated as needed.

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Additional Reading

• ICH Guidance on Viral Safety Evaluation of
  Biotechnology Products Derived from Cell Lines of
  Human or Animal Origin,1998 (www.fda.gov/cber/guid
  ance/)
• Points to Consider in the Manufacture and Testing
  of Monoclonal Antibody Products for Human Use,
  1997 (www.fda.gov/cber/guidance/)
• Guideline on General Principles of Process
  Validation, 1987 (www.fda.gov/cder/guidance/pv.htm
  )
• Reviewer Guidance Validation of Chromatographic
  Methods, 1994 (www.fda.gov/cder/guidance/)
• Validation of the Purification Process for Viral
  Clearance Evaluation, 1997, A.J. Darling, in
  Biopharmaceutical Process Validation, G. Sofer
  and D.W. Zabriskie, editors. Marcel Dekker, Inc
  (New York)

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Guidance

• CBER Office of Therapeutics 301-827-5101
• CBER Office of Vaccines 301-827-3070
• CBER Office of Blood 301-827-3524

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Obtaining Documents

• Fax (888) CBER-FAX
• Internet http//www.fda.gov/cber/guidelines.htm
• E-mail OCTMA_at_CBER.FDA.GOV
• Mail Training and Manufacturer Assistance
• (HFM-40) CBER/FDA
• 1401 Rockville Pike
• Rockville, MD 20852-1448