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Bench to Clinic of Biotherapeutic Molecules: Issues to Consider . By Dr. Michael Meagher Donald F. and Mildred T. Othmer Endowed Professor Director, Biological Process Development Facility Department of Chemical Engineering University of Nebraska-Lincoln. Objective of the Presentation.
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Bench to Clinic of Biotherapeutic Molecules: Issues to Consider By Dr. Michael Meagher Donald F. and Mildred T. Othmer Endowed Professor Director, Biological Process Development Facility Department of Chemical Engineering University of Nebraska-Lincoln
Objective of the Presentation • Provide the discovery scientist with information on what is required to move a “discovery molecule” to a “clinical candidate.”
Starting Point • Discovery has identified a protein with therapeutic properties. • Discovery wants to move the clinical candidate into preclinical testing.
Technology Transfer to Process Development and cGMP Manufacturing • Product characterization • Identify production cell line-Pichia pastoris • Analytical methods • Raw materials • Bench-scale process • Fermentation (shake flask) • Recovery • Purification • Formulation and stability
Product Characterization • The more characterization the better. • N-terminal sequencing • Tryptic digest and peptide map (LC-MS/MS) • Mass spectrometry • Overall mass • Post translational modifications • Amino acid analysis • Isoelectric focusing (pI) • Bioassay(s)
Cell Line • Discovery is accomplished through high-throughput expression systems. • Such expression systems are not intended or suitable for high-level production and cGMP manufacturing. • Therapeutic gene may not be optimized for scale-up and production.
Cell Line • Production expression system is determined based on the post translations modifications (PTM) that are required. • Bacteria to transgenic animal
Cell Line • The cell line is the most critical component of the production process. • Thorough characterization of the cell line is strongly recommended before moving a process into scale-up. • Prefer that a validated Master Cell Bank be established prior to process development.
Cell Line Evaluation • Shake flask • SDS-PAGE and Western Blot (minimum) • 5 L Bench-scale Fermentation • SDS-PAGE and Western blot (minimum) • Stability of supernatant (extra) or homogenate (intra) • Small-scale purification
Cell Line Evaluation-Case Study of BoNTC Hc expressed in Pichia pastoris • BoNTC Hc is expressed intracellular. • By shake flask there was no “apparent” effect of copy number on expression based on Western blot. • Evaluated 1, 2, 3 and 4 copy clones in a 5 L fermentor. • Standard basal salts media and trace minerals. • Methanol set point during induction was 1. 5 g/L.
USAMRIIDBotulinum Toxin ProgramDirected by Dr. Leonard Smith • Seven distinct serotypes (A-G) • Current vaccine is a pentavalent toxoid of serotypes A, B, C, E and F. Botulinum Toxin Zn Protease Membrane binding and translocation domain N C Light Chain (50 kd) Heavy Chain (100 kd) Vaccine
Effect of Gene Copy Number on Cell Growth During MeOH Induction
1.4 1.2 1 unit/unit of BoNTC(Hc) 0.8 293-1 0.6 299-2 300-3 0.4 301-4 0.2 0 0 10 20 30 40 50 Induction time (hr) Effect of Gene Copy Number on BoNTC(Hc) Production
Gene Copy Number Specific MeOH Growth Rate (hr-1) 1 0.0544 2 0.0231 3 0.0054 4 Not Constant 1.20 1.00 WB (old) 0.0166 0.80 BoNTC(Hc) maximum unit/unit of 0.60 0.40 0.20 0.00 0 1 2 3 4 5 Gene copy number Effect of Gene Copy Number on MeOH Growth Rate and Production of BoNTC Hc
BoNTC Hc Cell Line Case Study • The effect of BoNTC Hc copy number on MeOH metabolism was unexpected. • Essential to evaluate clones under production fermentation (and purification) conditions before deciding on a clone.
Establishing a Seed Bank • Purity • Determine the cell line is mono-culture • Identity • Phenotypic • Growth morphology • Carbon • Auxotrophic marker • Genotypic • Confirm and sequence gene insert • Restriction map • Ribosomal typing
Establishing a Seed Bank • Stability • Generational studies in shake flask and fermentor • Analyze product • Copy number • mRNA • All aspects of establishing a seed bank must be documented. Information is required for the Master Cell Bank.
Analytical Methods • Product characterization assays • Purpose is to sufficiently characterize the product so as to create a reference standard. • Bioanalytical reagents • Antibodies, cell lines for bioassay, enzymes, etc. • Essential to insure sources of these reagents.
Analytical Methods • In-Process Test(s) • Fast • Reliable • Robust • Quantitative for product • Able to handle all types of samples • Provide an indication that process is operating within specifications
Analytical Methods • Lot release assays for product • Amino acid analysis • Tryptic digest and peptide map • N-terminal sequencing • 2 HPLC methods and size exclusion • Endotoxins • SDS-PAGE and Western Blot • Reducing and non-reducing • Host protein and nucleic acids • Bioassay(s)
Process Description • Raw Material • Anything used to produce or analyze the product. • Important to specify several vendors. • Establish methods to I.D. raw materials. • Understand “shelf life” of raw materials.
Process Description-Fermentation • Monitor Critical Parameters-Metabolic Activity • pH • Dissolved oxygen • On-line sensors • Off gas • Calculate RQ and OUR • Consumption of nutrients, acid or base • Generate a fermentation history • Move towards greater computer control
Process Description-Purification • Recovery • The most difficult step in process development. • Purification • Identify critical parameters. • pH, conductivity, temperature, protein concentration, resin, membrane, etc… • Determine scalability of each step
Conclusions • The most critical “raw material” is the cell line. • Essential to evaluate cell lines under process development conditions. • The greater the interaction of the discovery scientists with the process development scientists and engineers the faster and more effective the transfer into the clinic.
Credit Goes To • Mehmet Inan (Molecular Biology) • Vijay Jain (Molecular Biology/Fermentation) • Wenhui Zhang (Fermentation) • Mark Gouthro (Fermentation) • Rick Barent (Purification) • Joey Wu (Purification)
Acknowledgements • BoNT Hc work was funded by the United States Army Medical Research and Materiel Command. • Contract No.: DAMD17-02-C-0107