Scaling Down Bioreactor Process Development: Comparison of Microbioreactor and Bench Scale Solutions.

Transcription

1 Scaling Down Bioreactor Process Development: Comparison of Microbioreactor and Bench Scale Solutions. Richard Lugg. Scientist I, MedImmune. European Laboratory Robotics Interest Group: High Throughput Bioprocess Development. 22 June 2011

2 Challenges Facing the Industry We are in an industry constantly under pressure to deliver high quality products:- Aiming for high titre manufacturing processes. Through efficient use of resources in a timely manner. Scaled down bioreactors can be one method of achieving this goal. 2

3 Typical Preclinical Project Plan. Vectors Parental cell lines Static 24 Well Plate Cell Lines Clonal cell lines Static 24 Well Plate Cell Lines Phenotypic Cell Line Stability Lead Clone Selected Bioreactor Process Development Process Lock Suspension Shake/T Flask 50 Cell Lines Suspension Shake Flask 50 Cell Lines Suspension Shake Flask 6-8 Cell Lines Bioreactor Platform Process 6-8 Cell Lines Bioreactor Process Optimisation 1 Cell Line Multiple Bioreactors / Flasks 3

4 Typical Preclinical Project Plan. Vectors Parental cell lines Shaking plate (suspension) 24 Well Plate Cell Lines Suspension Shake/T Flask 50 Cell Lines Shaking plate (suspension) 24 Well Plate Cell Lines Clonal cell lines Suspension Shake Flask 50 Cell Lines Phenotypic Cell Line Stability Suspension Shake Flask 6-8 Cell Lines Bioreactor Platform Process 6-8 Cell Lines Lead Clone Selected Bioreactor Process Development Bioreactor Process Optimisation 1 Cell Line Multiple Bioreactors / Flasks Process Lock 4

5 Early cell line screening in static/suspension plates. Screening for the Best Cell Lines. Best clones evaluated in shake flasks. 100s 10s Only the final few (<10) are taken forward to bioreactors. In an ideal world every cell line would be evaluated in a bioreactor. <10 5

6 Improving Quality of Data Ease of Handling? Quality of Data 6

7 New Technologies for Screening Cells New technologies can now offer better scale down models of our cell culture and bioreactor processes. Old technology Possible new approaches Static 96 well Plate Shaken 24 well Plates (semi-automated)* Scale-down Bioreactor System Fed Shake Flask Micro-24 - Pall SimCell Seahorse Bioscience *Silk et al. Biotechnology Letters (2010) ambr - TAP Biosystems 7

8 ambr - TAP Biosystems TAP Biosystems saw a need for a scaled down bioreactor. Approached MedImmune for our input in development of the system. Gave us scope to try another system that could be tailored to our requirements. 8

9 ambr Background ambr microbioreactor. Automated. Liquid handling deck. Cell culture manipulation. > Inoculation. > Feeding. > Sampling. Disposable stirred bioreactor vessels. 24 or 48 vessels can be run at same time. 7mL-15mL working volume. Bioreactor control. ph. Temperature. Dissolved oxygen. Stirrer speed. TAP Biosystems. 9

10 Liquid Handling Deck Liquid handling arm Vessels (24 total) Inoculum, medium, feeds or sample cups Tips for feed addition / sampling 2 Cell culture stations (24 vessel format). 12 vessels per culture station. 1 temperature setting for each cell culture station. 1 stirrer speed setting for each cell culture station. 2 deck for pipette tips. 4 decks for reagents and sampling lab ware. 10

11 Disposable Vessel. Inlet / outlet for fluids Open pipe sparger ph and O 2 sensors Impeller Gamma irradiated for sterility. Presens fluorescence sensors for ph and O 2 sensors. 3 Gasses can be added through the sparger. Each vessel can have different ph, dissolved oxygen set points. Separate feeding regimes. Measurements taken every 90 seconds. 11

12 Considerations This technology requires a dedicated laminar airflow hood. Some infrastructure for gases. User handling required during run to replace tips, offline analysis etc. Flexibility. Simple to use. Extra Considerations When Using ambr 12

13 Does =? 13

14 Vessel to Vessel Reproducibility. Batch over grow experiment ran using 24 vessels in batch with the same condition. Conditions. > ph, DO, temperature control. > No feed/glucose additions made. Off Line Analysis. > Cell counts were made using a Vi-CELL (Beckman Coulter). > ph compared with using a blood gas analyser (Radiometer). 14

15 ambr Batch Overgrow Data. Good consistency between vessels was observed. Dotted lines show 3 standard deviations (SD) from the mean of the data. Data falls within the dotted lines. No differences between culture stations. No corner affects. No back row Vs front row affects. 120 Viable cell profile. Viable Cells/mL Key: Ambr : Orange and Red Mean in Black Solid 3SD from mean in Black Dotted Days 15

16 ambr Batch Over Grow Data. ph Lower Limit ph SP Upper Limit Off line ph Profile Days ph was controlled within range (ph SP ± 0.10). pco 2 as expected for batch data. pco2 (mmhg) Off line pco 2 Profile Days 16

17 ambr Batch Over Grow Summary. Good vessel to vessel comparability. No positional effects. Front to back. Side to side. Culture station to culture station. ph well controlled for all vessels but it is slightly different in the microbioreactor in comparison to a benchtop bioreactor. 17

18 ph ph control strategy. In ambr ph is controlled by addition of carbon dioxide or a base solution as for a benchtop bioreactor. There are subtle differences in the control of ph: Base additions are discontinuous with ambr where a benchtop bioreactor base addition is continuous. You have to determine a target value for the base addition to bring the ph back up to (see example below). Example: Here the base additions are made on days 5 and 7 to target a ph of 6.90 (half way between the SP and lower limit) Upper Limit ph SP 6.80 Lower Limit

19 Gassing. Further Optimisation of Process. Ballast flow rates can be optimised for process. Move to use same gases as benchtop bioreactor. Manual nature of the glucose measurements using the hand held meter became laborious. Implemented a YSI2700 with 24 sample turntable. ph control. ph profiles showed similar trends but base addition optimised to achieve similar profile to benchtop at the lower limit. Lower target base additions sets for fine tuning of ph the control. 19

20 Clone Ranking Experiment 24 vessels used to examine the ranking of 6 different clones using fed batch method. Each clone was evaluated in duplicate. 2 different gas flow rates. Controls. > Stirrer speed increased during run based on O 2 demand. > DO, temperature control kept constant. > ph with dead band used. > Bolus nutrient and glucose feed additions made. Off Line Analysis. > Cell counts were made using a Vi-CELL (Beckman Coulter). > Offline ph was measured using a blood gas analyser (Radiometer). > A YSI2700 instrument was used to measure glucose and lactate. Data was compared to that generated in benchtop bioreactor (DASgip). 20

21 ambr Vs Benchtop Bioreactor Data. Viable Cells / ml (e6) Viable Cell Number Profile Days Upper 6.90 limit 6.85 ph Off line ph Profile ph SP Lower limit Days A1 A19 A7 A13 D1 A1 A19 A7 A13 D1 Red line shows benchtop bioreactor data and blue line shows ambr data. 1 cell line shown as all clones were similar in their profiles. Viable cell count good reproducibility between ambr vessels difference towards end of run due to using different Vicell for ambr and benchtop bioreactor data. ph profile is very similar between ambr and benchtop bioreactor. 21

22 ambr Vs Benchtop Bioreactor pco 2 Profile pco pco D a y s A 1 A 1 9 A 7 A 1 3 D 1 Shows similar drop in pco2 between ambr and benchtop bioreactor over time course. The separate pco 2 profiles in ambr due to the different ballast flow rates. 22

23 Glucose and Lactate Profiles. Glucose Profiles. Lactate Profiles. 6 5 Glucose g/l Lactate g/l Days A1 A19 A7 A13 D Days A1 A19 A7 A13 D1 General trends in the ambr are comparable to the benchtop bioreactor. 23

24 Clone Ranking: Summary Generally cells grow better in the ambr than in benchtop bioreactors. Higher IVC and higher maximum viable cell density reached. Specific productivity (pg/cell/day) was similar between ambr and benchtop bioreactors. Titre is usually higher in the ambr compared with the bench top bioreactor vessels due to higher IVC. How does the clone ranking look? 24

25 Clone Ranking on Titre. End of Run Titre Final harvest titre of top 2 cell lines ranked in the same order by ambr and benchtop bioreactor. Titres > 3.5g/L. Final harvest titre of other 4 cell lines in a different order. Small data set for these cell lines at benchtop scale makes it more difficult to differentiate between the different clones. Need to run more benchtop bioreactors to verify ranking order. 25

26 Clone Ranking Conclusions. Good vessel to vessel reproducibility in the ambr system. Very tight data set generated for the batch and fed batch ranking studies. Good process control in ambr comparable to benchtop systems. Allows for process optimisation (ph, DO, etc). Clone ranking in microbioreactor compared to benchtop bioreactor systems is ok. We need to build further data sets. > Parallel experiments using both benchtop bioreactors and ambr needed. > Potential to push bioreactor screening earlier in our preclinical project plan. 26

27 Typical Preclinical Project Plan Vectors Parental cell lines Shaking plate (suspension) 24 Well Plate Cell Lines Suspension Shake/T Flask 50 Cell Lines Shaking plate (suspension) 24 Well Plate Cell Lines Clonal cell lines Suspension Shake Flask 50 Cell Lines Phenotypic Cell Line Stability Suspension Shake Flask 6-8 Cell Lines Bioreactor Platform Process 6-8 Cell Lines Lead Clone Selected Bioreactor Process Development Bioreactor Process Optimisation 1 Cell Line Multiple Bioreactors / Flasks Process Lock 27

28 Future Preclinical Project Plan? Bioreactor Platform Process? Vectors Parental cell lines Shaking plate (suspension) 24 Well Plate Cell Lines Bioreactor Platform Process? Shaking plate (suspension) 24 Well Plate Cell Lines Clonal cell lines Suspension Shake Flask 50 Cell Lines Phenotypic Cell Line Stability Suspension Shake Flask 6-8 Cell Lines Bioreactor Platform Process 6-8 Cell Lines Lead Clone Selected Bioreactor Process Development Bioreactor Process Optimisation 1 Cell Line Multiple Bioreactors / Flasks Process Lock 28

29 Efficient use of resources is important. Microbioreactor systems as alternative to shake flasks/benchtop bioreactors. This technology can be applied earlier in our process than traditional bioreactors. Allowing for screening multiple cell lines in a manufacturing environment. Further process development and optimisation on a limited panel of cell lines for higher titre manufacturing process. Bioreactor quality data with shake flask resource. Better decision making during clone screening. Summary 29

30 Efficient use of resources. 6 Benchtop bioreactors. 24 microbioreactors. 30

31 ambr Acknowledgments Gareth Lewis, Alison Mason, Rahul Pradhan, Diane Hatton and Ray Field. Early Stage Bioreactor Team and Cell Sciences Group at MedImmune. From TAP Biosystems. > Richard Wales, Neil Bargh, Kenneth Lee, Dave Savage. 31

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