continuous and semi-continuous cell culture for production ......continuous and semi-continuous cell...
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Continuous and Semi-continuous Cell Culture for Production of Blood Clotting Factors
Sunil G. Desai, Ph. D. Sr. Manager, Manufacturing Sciences and Technology
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Sanford , NC
Grange Castle, Ireland Andover, MA
Pearl River, NY
Pfizer Biotech
CMOs
Strangnas, Sweden
Algete, Spain
Biologics Vaccines Biosimilars Robust pipeline
BeneFIX or rFIX
• Recombinant therapy for Factor IX deficiency (hemophilia B)
• 55 kDa zymogen with 12 γ-carboxylation sites
• Several other complex post-translational modifications
• Extensive structure and functionality assays
• First approved recombinant factor IX product (1997)
• CHO-based batch re-feed process • ADRM free culture medium from
the beginning
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318316
312
3
ReFacto AF/ Xyntha or BDD-rFVIII
• Recombinant therapy for Factor VIII deficiency (hemophilia A)
• FVIII gene sequenced in 1984 • Engineered version of FVIII (B
domain deleted), maintains procoagulant function
• Increased transcription efficiency • ReFacto approved in U.S., EU (1st
licensed in 1999) • ReFacto AF approved in 2008 • CHO-based perfusion process • DS manufactured at an external
partner site for Pfizer
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Full Length FVIII
NH2 90 B 80 COOH
ReFacto
NH2 COOH 90 80
50 43
73
Me2+
Activated ReFacto
3D picture reference: Orlova et al., 2013, Acta Naturae, 5(2).
Key Process Challenges
• Low level expression (transcription/ translation level) • Growth associated expression • Labile product
– Degradation during processing – Activation during processing
• Complex post-translational modifications – Disulfide bond formation (11 for rFIX) – N-linked and O-linked glycosylation – Tyrosine sulfation (rFVIII, rFIX) – Metal ion binding – Heavy and light chain cleavage – γ-carboxylation sites
• Process changes while maintaining quality/ comparability – Removal of ADRMs (Albumin) from culture medium (BDD-rFVIII) – Changes in production sites/ scales – Use of disposables – Ongoing process updates (PAT, vendor changes, ICH guidelines)
• Supply sensitive customer base
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Cell culture process - BeneFIX
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Low cell density
Bio
reac
tor
Har
vest
Re-
feed
Recovery Nutrient media
Seed
Re-feed Process
High cell density
Retained culture
Low cell density
After n days
BeneFIX production data
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BeneFIX (1997 – present)
Non-validated database of GMP data Bioreactor
Num
ber o
f bat
ches
2.5kL 6kL 12kL
1 2 3 4 5 6 7 8 10 9 11
Benefits/ challenges of continuous process
•Productivity vs Titer – Perfusion/ re-feed processes reduce BRX turn-around time – Lower product quality risk than increasing specific productivity of cells – Easy to model volumetric productivity vs titer benefit analysis
8 •Data from multiple bioreactors •Range of variation in productivity yet consistent product quality
LCL
Bioreactor batch
Cel
l Spe
cific
Pro
duct
ivity
0 Non-validated database of GMP data
Benefits/ challenges of continuous process
•Campaign lengths – Several weeks to months – Multiple bioreactors allow back up inoculation sources – Savings in reduced SIP/ CIP cycles of bioreactors
•Number of cell generations
– Extensive LIVCA studies required • At scale EOP samples tested for genetic stability
– Routine testing for culture purity (mycoplasma and virus) at EOP only
– Additional product characterization to account for cell age (early-mid-late stage campaign effects)
– CHO, in general, stable for extended number of generations
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Specific growth rate vs generations
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•Growth rate is independent of cell generation number •Range in growth rate giving consistent product quality
Culture generations
Spe
cific
gro
wth
rate
LCL
0 85
Non-validated database of GMP data
Benefits/ challenges of continuous process
• Maintenance of aseptic BRX conditions for extended time – A major concern with extended period cell culture – SIP / CIP procedures have vastly improved • Years of experience • Multiproduct facilities • Rigorous PM and engineering controls (o-rings!) • Disposable use with minimum open operations
11 1.3% contaminated Two of eleven bioreactors were never contaminated
Campaign
Bat
ch c
ount
Contaminated batches
Non-validated database of GMP data
Period with non contaminations
Cell culture process – ReFacto AF
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Culture medium
Cell separator
Return of CHO cells to the bioreactor
Harvest of product containing broth
Bioreacto
To clarification, primary capture
Perfusion Process
Bioreactor
Harvest tank
ReFacto AF •New MCB for HSA-free ReFacto
– Same cell lineage, BDD-rFVIII genotype unchanged – Albumin-free media for production
•Replace hybridoma-derived MAb column •Analytical Comparability
– Very similar biochemical profile – Relationship to historical ranges well understood
•Non-clinical/Clinical Comparability
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ReFacto 2.0 1.6 1.2 0.8 0.4
0
ReFacto AF
15 20 25 30 35 40 45 50 55
1.6 1.2 0.8 0.4
0
2.0 2.4
Time (minutes)
1 2 3 4
Lane Sample
1 MW Markers 2 Blank 3 ReFacto (Site 1) 4 ReFacto (Site 2) 5 ReFacto AF
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Kelley et al., 2009, Haemophilia.
80 kDa
170 kDa 90:1 90:2
ReFacto AF production data
14 Consistent product quality data over the years
~5 years of data shown
Non-validated database of GMP data
LCL
LCL
UCL
UCL
% P
rodu
ct
Isof
orm
1
Sp.
Act
ivity
Bioreactor 1 Bioreactor 2
Chromatography 2
Bioreactor 3
Harvest and Cell Separation
Concentration/Diafiltration by Ultrafiltration 1
Chromatography 1
BeneFIX
Purification
Bioreactor
Harvest and Cell Separation
Chromatography 1Frozen eluate
ReFacto AF
Viral inactivation &
Purification
Eluate pool
Benefits/ challenges of continuous process
• Critical for biologics from a compliance perspective
• Each DS lot traces back to a single cell bank thaw event
• Pooling of multiple batch streams during purification
• Batch stream could originate from multiple scales
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Batch definition
Conclusions
• Semi-continuous (re-feed) and continuous (perfusion) processes of complex recombinant proteins commercially successful for over 15 yrs
• Product/ process life-cycle changes successfully implemented • Large data sets demonstrate process robustness and cell line
stability • Increased plant productivity with shorter bioreactor turn-
around times • Manageable contamination rates over extended periods of
operation add substantial operational savings
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Acknowledgements
Almost two decades of contributions towards continuous development and manufacturing of BeneFIX and ReFacto AF/ Xyntha
– Pfizer Global Supply (Tanya Alcorn) Site Operations (Erin Beal, Erik Roos) Quality Manufacturing Sciences and Technology (Dan Lasko,
Enda Moran, Kesav Reddy, Jim Booth) – Pharmaceutical Sciences (Tim Charlebois, Mike Jankowski,
Shamik Sharma) – External supply partners