Advisory Committee for Pharmaceutical Science

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Advisory Committeefor Pharmaceutical Science

• Process Analytical Technology
• and Biotechnology Products
• Keith O. Webber, Ph.D.
• Office of Biotechnology Products
• OPS/CDER
• April 13, 2004

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Which Products?
Biological Products include
Blood and Blood Products Vaccines Allergenic
Products Cell Therapies Gene Therapies Recombinant
DNA-derived Protein Products
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Which Products?
Biological Products include
Blood and Blood Products Vaccines Allergenic
Products Cell Therapies Gene Therapies
Recombinant DNA-derived Protein Products
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Two Aspects of PAT

• Monitoring product characteristics or surrogates.
• Monitoring and modulating critical process
  parameters to guide the product characteristics
  during processing.

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Process Analytical Technology
Process
Monitor
Adjust
Decision
Data
Evaluate
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Biotechnology Processes
Concentration
Harvesting
Product Capture
Fermentation
Chromatography
Formulation
Filtration
Lyophilization
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Biotech API Characteristics

• Primary structure
• (amino acid sequence)
• Secondary structure
• (local interactions)

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Biotech API Characteristics

• Tertiary structure
• (domain interactions)
• Quaternary structure
• (subunit interactions)

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Biotech API Characteristics

• Post-translational modifications
• Glycosylation
• Proteolysis
• Acylation
• Sulfation
• many others

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Biotech Product Characteristics

• Impurity profile
• Process-related impurities
• Media components
• Host cell proteins
• Leachates
• Product-related impurities
• Truncations
• mis-foldings
• aggregates

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Analytical MethodsPrimary Structure

• Methods
• amino acid analysis
• protein sequencing
• peptide mapping
• mass spectrometry
• immunoassay

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Analytical MethodsSecondary Structure

• Methods
• circular dichroism
• NMR

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Analytical MethodsTertiary Quaternary Structure

• Methods
• Functional assay
• Immunoassay
• Peptide mapping (for mapping disulfides)
• Size-exclusion chromatography
• Hydrophobic-interaction chromatography

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Analytical MethodsPost-translational
Modifications

• Enzymatic cleavage analysis
• Mass spectroscopy
• NMR
• Immunoassay
• Peptide mapping
• Functional assay

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Inherent Challenges
Biotech products are large, complex, plieotropic
molecules - mixture of post-translational
modifications - multiple active sites -
homologous - heterologous - activities are
dependent on complex, folded conformations -
susceptible to multiple degradative events -
proteolysis, aggregation, mis-folding, oxidation,
deamidation, etc.
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Factors to Consider
Purity Potency Strength Pharmacokinetics Pharmaco
dynamics Immunogenicity
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Fermentation Processes
Control Agitation pH Ionic strength Temperature
Dissolved O2 CO2 Media components Growth
rate Expression rate
Monitor Agitation pH Ionic strength Temperature
Dissolved O2 CO2 Media components Biomass Biobur
den (sterility, mycoplasma) Light absorbance
(e.g., A280)
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Chromatographic Processes
Control pH Ionic strength Flow
rate Temperature Volume
Monitor pH Ionic strength Flow
rate Temperature Volume Bioburden Light
absorbance
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Filtration Processes
Control Temperature Flow rate Back-pressure Volu
me
Monitor Temperature Flow rate Back-pressure Volu
me Bioburden Light absorbance
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Lyophilization
Control Shelf temperature Product
temperature Chamber Pressure Condenser
temperature Condenser pressure Time Freezing
rate Drying rate Product moisture content
Monitor Shelf temperature Product
temperature Chamber Pressure Condenser
temperature Condenser pressure Time
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Questions

• What technologies are available now to evaluate
  the characteristics of protein products in real
  time during manufacturing?
• What tools would allow us to understand the
  manufacturing process better?
• What processes in biological drug manufacturing
  would benefit the most from implementation of
  PAT?
• For processes or products that do not currently
  allow direct product quality monitoring, what
  other strategies do you recommend for product
  quality control in addition to control of
  in-process parameters?
• What additional elements should be incorporated
  in a training and certification program for
  reviewers and inspectors of biotechnology PAT
  applications?