The Future of Viral Validation. Howard L. Levine, Ph.D. Process Validation for Biologicals Carlsbad, CA February 26 27, 2007

Transcription

1 The Future of Viral Validation Howard L. Levine, Ph.D. Process Validation for Biologicals Carlsbad, CA February 26 27, 2007

2 Virus Safety Evaluation and Validation Increased scrutiny and requirements for viral safety by regulatory agencies Harmonization of regulations using risk-based approach More stringent requirement for robust clearance steps Greater emphasis on design of scale down models and viral clearance studies Use of more sensitive assays for detection of virus

3 Definition of Robust Unit Operation Separation follows anticipated mechanism of action Highly reproducible log reduction values (LRV) attained using a defined set of process parameters Process parameter design space defined and supported by appropriate data LRV not affected by variations in process parameters within the experimental design space Partitioning of virus is determined Ref: G. Blank, PDA Viral Safety Workshop, 2005

4 Documented Robust Viral Clearance Steps Ref: K. Brorson, PDA Viral Safety Workshop, 2005

5 Case Study Changing Requirements for Design of Viral Clearance Studies

6 Product History Big Biotech developed Blockbuster Viral clearance studies performed in 1999 to support a Phase 3 clinical trial Clinical trial successfully initiated Big Biotech discontinued development of product for business/strategic reasons Product rights subsequently sold to Little Biotech Little Biotech successfully transferred manufacturing process to their facilities in 2005 Identical scale and identical unit operations Biochemical comparability of product and process demonstrated In 2006, Little Biotech filed for permission to re-initiate Phase 3 trials

7 Virus Removal by Filtration Log Reduction Values Run 1 Run 2 Viral Load Log Reduction Value Viral Load Log Reduction Value Virus Initial Final Initial Final XMuLV 6.19 < 0.75 > < 0.75 > 4.92 PRV 6.67 < < Reo < < PPV Data from Big Biotech 1999 viral clearance studies

8 Changing Requirements for Viral Clearance Studies Regulatory agencies place product on clinical hold, requesting repeat of viral clearance study for nanofiltration step, citing deficiencies in previous study design Relatively low titer of viruses used in clearance study Lack of step to remove viral aggregates in virus spike for clearance study Viral safety testing laboratories report removal of viral aggregates NOT generally incorporated into studies until early 2000 s

9 Nanofiltration One of the most common steps used in bioprocessing for viral clearance A virus specific mechanism of action that complements other technologies Single use technology eliminates need for complex virus clearance evaluations associated with other technologies e.g., column chromatography Robust when process parameters are well understood Filtration is a unit operation that forms part of the overall virus clearance assessment for the process

10 Virus Aggregates Virus aggregates can cause reduced clearance values in inactivation studies and increased clearance values in size-exclusion studies Aggregate-free stocks can form aggregates upon introduction of the virus into the load material for the step being studied Evaluate the formation of viral aggregates by pre-filtering the virus-spiked load material prior to performing the step being tested

11 Aggregation Assessment in XMuLV Lots Virus Lot Titer (Log 10 TCID 50 /ml) Lot Titer (Log 10 TCID 50 /ml) Unfiltered 0.22 µm Filtered Difference Unfiltered 0.45 µm Filtered Difference XMuLV A G B H C I D J E K F Data courtesy of Invitrogen Bioservices

12 Aggregation Assessment in MMV Lots Virus Lot Titer (Log 10 TCID 50 /ml) Lot Titer (Log 10 TCID 50 /ml) Unfiltered 0.1 µm Filtered Difference Unfiltered 0.1 µm Filtered Difference MMV A G B H C I D J E K F Data courtesy of Invitrogen Bioservices

13 Aggregation Assessment in Feedstream Virus Prefilter No Aggregation (SL II 1.0 log of SL I) Aggregation (SL II > 1.0 log of SL I) Total # Studies % # Studies % XMuLV ( nm) 0.1 µm 0.22 µm % 76% % 24% µm 30 81% 7 19% 37 Summary 61 77% 18 23% 79 MMV (20-25 nm) 0.1 µm 0.22 µm % 84% 0 5 0% 16% µm 16 80% 4 20% 20 Summary 59 87% 9 13% 68 Data courtesy of Invitrogen Bioservices

14 Modern Design of Virus Removal Study Load Virus Spike Spiked Load I + Hold Control Prefilter Spiked Load II Virus Removal Filter Hold at process temperature Retentate Permeate 1 Permeate 2 Permeate 3 Assay ETC. Courtesy of Invitrogen Bioservices

15 Sample Results from Filtration Study Sample Viral Load (log 10 TCID 50 /ml x Volume x Correction Factors) XMuLV ( nm) Reo 3 (60-80 nm) IBR ( nm) BVDV (40-70 nm) BPV (20-25 nm) Spiked Load III 6.40 ± ± ± ± ± % Permeate! 2.56! 2.56! 1.86! 2.56! % Permeate! 2.56! 2.30! 1.78! ± % Permeate! 2.29 ND! 1.31 ND 5.29 ± % Permeate! 2.91! 2.75! 2.10! ± % Permeate (large volume)! 1.95! 1.79! 1.67! 1.84 " 3.65 ± 0.00 Data courtesy of Invitrogen Bioservices

16 Improved Assays for Measuring Viral Clearance

17 Methods for Assaying Virus

18 Validation of Q-PCR Assay Ref: Q. Chen, PDA Viral Safety Workshop, 2005

19 Clearance of XMuLV Ref: Q. Chen, PDA Viral Safety Workshop, 2005

20 Clearance of MMV Ref: Q. Chen, PDA Viral Safety Workshop, 2005

21 Summary What is the future of viral validation? More of the same with greater emphasis on design of clearance studies and detection methods