1 validation of bone allograft processing: reducing risk of disease transmission via conventional...

1

Validation of Bone Allograft Processing:

Reducing Risk of Disease Transmission via Conventional Agents While Maintaining Graft Performance

Validation of Bone Allograft Processing:

Reducing Risk of Disease Transmission via Conventional Agents While Maintaining Graft Performance

TSE Advisory Committee Meeting

June 26, 2002

Gaithersburg, MD

TSE Advisory Committee Meeting

June 26, 2002

Gaithersburg, MD

Richard Russo

Osteotech, Inc.

2

Validation of Bone Allograft ProcessingValidation of Bone Allograft Processing

Risk reduction is a multi-functional process, built on several factors:

Donor testing and screening Donor deferral and tissue discard policies Appropriate segregation and quarantine procedures Adequate cleaning and disinfection between batches Processing to inactivate and/or remove pathogens

Risk reduction is a multi-functional process, built on several factors:

Donor testing and screening Donor deferral and tissue discard policies Appropriate segregation and quarantine procedures Adequate cleaning and disinfection between batches Processing to inactivate and/or remove pathogens

3


Potential pathogens in tissue: Bacteria, yeasts, mold and fungi Viruses TSE

Presentation focus: Viruses in standard non-demineralized grafts

Principal viruses of concern: HIV 1 + 2, HTLV 1+2, HBV, HCV

Potential pathogens in tissue: Bacteria, yeasts, mold and fungi Viruses TSE

Presentation focus: Viruses in standard non-demineralized grafts

Principal viruses of concern: HIV 1 + 2, HTLV 1+2, HBV, HCV

4


Performance

Primary purpose of bone graft is to support bone formation across a defect due to disease, trauma, or reconstructive surgery

Not all processing has same effect on bone graft performance

Failure of graft procedure typically leads to revision surgery

Limitation of capacity of graft to support bone formation leads to increased morbidity and risk to patient

Performance

Primary purpose of bone graft is to support bone formation across a defect due to disease, trauma, or reconstructive surgery

Not all processing has same effect on bone graft performance

Failure of graft procedure typically leads to revision surgery

Limitation of capacity of graft to support bone formation leads to increased morbidity and risk to patient

5

Validation of Bone Allograft Processing:Treatments Affecting Performance

Validation of Bone Allograft Processing:Treatments Affecting Performance

Preprocessing Storage Temperature Multiple Freeze-Thaw Cycles Sterilization Procedures

UV Radiation Gamma E-beam Ethylene Oxide

Solvents (GnHC1, Acid-Alcohol, EDTA) Sonication (> 20,000 cycles/sec.) Peracetic Acid Hydrogen Peroxide

Concentration and time dependent Strong base, e.g, NaOH

Reviewed by Russell & Block, Orthopedics Vol. 22 (5); 524, 1999

Preprocessing Storage Temperature Multiple Freeze-Thaw Cycles Sterilization Procedures

UV Radiation Gamma E-beam Ethylene Oxide

Solvents (GnHC1, Acid-Alcohol, EDTA) Sonication (> 20,000 cycles/sec.) Peracetic Acid Hydrogen Peroxide

Concentration and time dependent Strong base, e.g, NaOH

Reviewed by Russell & Block, Orthopedics Vol. 22 (5); 524, 1999

6

3.5

2.27

00

1

2

3

4

Graft A Graft B Graft C

NASS Proceedings, 15th Annual Meeting 2000, p38

Validation of Bone Allograft Processing

Comparison of Osteoinductivity: Independent Published Study

7


Risk reduction via processing begins with characterization of tissues and assessment of risk

Each type of tissue presents its own profile

Musculoskeletal tissues can be characterized as soft or hard

Soft: ligaments, tendons, fascia, cartilage Hard: bone

• Cancellous• Cortical

Risk reduction via processing begins with characterization of tissues and assessment of risk

Each type of tissue presents its own profile

Musculoskeletal tissues can be characterized as soft or hard

Soft: ligaments, tendons, fascia, cartilage Hard: bone

• Cancellous• Cortical

8


In terms of mass, bone tissue can be described as having two phases:

Inorganic

Organic

In terms of mass, bone tissue can be described as having two phases:

Inorganic

Organic

9


Mineral (70%)

Hydroxyapatite (95%)+

MagnesiumSodium

PotassiumFluorideChloride

Organic (30%)

Cells (2%)OsteoblastsOsteocytesOsteoclasts

+Matrix (98%)Collagen (95%)

Non-collagenous proteins (5%)(includes growth factors)

Composition of Normal Bone

10


11


Structure of Cortical (Compact) Bone

13


No published reports that quantitative viral burden in bone

Extrapolate viral burden from values reported for blood: data exist for HIV, HTLV, HBV, and HCV

Bone is divided into discrete compartments

Conservative bone allografts “dose” 90cc mineralized tissue

Calculation of blood volumes

Calculation of theoretical maximum viral burden

No published reports that quantitative viral burden in bone

Extrapolate viral burden from values reported for blood: data exist for HIV, HTLV, HBV, and HCV

Bone is divided into discrete compartments

Conservative bone allografts “dose” 90cc mineralized tissue

Calculation of blood volumes

Calculation of theoretical maximum viral burden

Maximum Viral Burden in Bone: General Considerations

14


Spike bone with known amount of virus

Relevant panel

Demonstrate quantitative recovery

Proceed through process step

Quantitatively assay viral inactivation

Calculate difference between theoretical maximum viral burden and log reduction value of process

Viral clearance must be at least 3 logs greater than maximum viral burden to provide acceptable level of safety

Spike bone with known amount of virus

Relevant panel

Demonstrate quantitative recovery

Proceed through process step

Quantitatively assay viral inactivation

Calculate difference between theoretical maximum viral burden and log reduction value of process

Viral clearance must be at least 3 logs greater than maximum viral burden to provide acceptable level of safety

Viral Clearance Process Validation: General Approach

15


HIV HBV HCV

IU/ml Blood 50 x 10³ 10³ 10 x 10³

IU/cc Bone

(0.015ml/cc) 5 x 10² 10¹ 10²

IU/ bone dose

(15cc) 7.5 x 10³ 1.5 x 10² 1.5 x 10³

Log IU/ dose

(highest value) 3.87 2.18 3.18

Estimated Theoretical Maximum Viral BurdenDemineralized Bone

16


HIV-1 HTLV-1 HTLV-2 HBV HCV

Inactive Marrow 2.3-5.0 1.5-3.5 1.5 1.8-4.3 2.8-7.8

Active Marrow 5.3-8.6 4.6-6.6 4.6 1.8-4.3 4.6-8.6

Log values

Maximum Viral Burden: Mineralized Bone

17


Viral Inactivation - D-MIN® Process

Step HIV

DHBV

(HBV)

BVD

(HCV) CMV Polio

HCL >5.23 >3.70 >4.15 >2.92 >5.99

EtOH >4.23 >3.70 >3.15 >3.32 >3.72

Lyophilization None N.D. 1.77 None 2.30

Total >9.46 >7.40 >9.07 >6.24 >12.01

MAX Burden 3.87 2.18 3.18 N/A* N/A*

Safety Factor 5.59 5.22 5.89

Log10 Reduction

*Insufficient published data to calculate viral burden.

18

Validation of Bone Allograft Processing Standard Bone Allografts

Viral Inactivation and Removal Data

HIV BVD DHBV CMV Polio

Step 3 Surfactant

Inactivation5 Min >4.38 >4.59 None >5.09 None

Step 8 AlcoholInactivation

5 min >4.38 >4.59 >3.50 >5.09 0.53Total

Inactivation>8.76 >9.18 >3.50 >10.18 0

Step 4/2 Removal MuLV BVD BVD HSV Polio

1 min 6.15 6.21 6.21 6.68 8.3Total

Clearance:14.91 15.39 9.71 16.86 8.3

Theoretical Max. Viral

Burden 5.3-8.6 4.6-8.4 1.8-4.3 ND ND

Safety Factor 6.31 6.99 5.41 - -

19

Current process validation guidance documents and virology perspectives can be successfully adapted to viral clearance process validation for bone allografts

Bone allograft performance can be maintained while producing a significant SAL using a conservatively calculated theoretical maximum viral burden

Current process validation guidance documents and virology perspectives can be successfully adapted to viral clearance process validation for bone allografts

Bone allograft performance can be maintained while producing a significant SAL using a conservatively calculated theoretical maximum viral burden


20


Center for Biologics Evaluation and Research. “Points to Consider in the Characterization of Cell Lines Used to Produce Biologicals” (Food and Drug Administration) 1993

Center for Biologics Evaluation and Research. “Points to Consider in Manufacture and Testing of Monoclonal Antibody Products for Human Use” (Food and Drug Administration) 1997

Committee for Proprietary Medicinal Products Ad Hoc Working Party on Biotechnology/Pharmacy and Working Party on Safety Medicines, Note for Guidance. “Validation of Virus Removal and Inactivation Procedures”, Biologicals 1991: 19-247-251

Committee for Proprietary Medicinal Products: EEC Council Directive 89/381: “Medicinal Products Derived from Human Plasma” (Revised Draft 1995)

Center for Biologics Evaluation and Research. “Points to Consider in the Characterization of Cell Lines Used to Produce Biologicals” (Food and Drug Administration) 1993

Center for Biologics Evaluation and Research. “Points to Consider in Manufacture and Testing of Monoclonal Antibody Products for Human Use” (Food and Drug Administration) 1997

Committee for Proprietary Medicinal Products Ad Hoc Working Party on Biotechnology/Pharmacy and Working Party on Safety Medicines, Note for Guidance. “Validation of Virus Removal and Inactivation Procedures”, Biologicals 1991: 19-247-251

Committee for Proprietary Medicinal Products: EEC Council Directive 89/381: “Medicinal Products Derived from Human Plasma” (Revised Draft 1995)

21


Committee for Proprietary Medicinal Products: 1995 Revised CPMP Guidelines. Virus Validation Studies: The design, contribution and interpretation of studies validating the inactivation and removal of viruses (revised)

ICH Viral Safety Document: QSA Viral Safety Evaluation of Biotechnology Products Derived from Cell Lines of Human or Animal Origin: 1998

Committee for Proprietary Medicinal Products: 1995 Revised CPMP Guidelines. Virus Validation Studies: The design, contribution and interpretation of studies validating the inactivation and removal of viruses (revised)

ICH Viral Safety Document: QSA Viral Safety Evaluation of Biotechnology Products Derived from Cell Lines of Human or Animal Origin: 1998

22

Validation of Allograft Bone ProcessingValidation of Allograft Bone Processing

Spike Samples – Hamster Scrapie Homogenate Evaluation by prion Western Blot Assay Solid surface cleaning with existing procedures

Log Reduction Factors

Solid surface cleaning – Sporklens > 4.0 Solid surface cleaning – Expor (1) > 3.4 Solid surface cleaning – Expor (2) > 3.4

Spike Samples – Hamster Scrapie Homogenate Evaluation by prion Western Blot Assay Solid surface cleaning with existing procedures

Log Reduction Factors

Solid surface cleaning – Sporklens > 4.0 Solid surface cleaning – Expor (1) > 3.4 Solid surface cleaning – Expor (2) > 3.4

Prion Inactivation by Cleaning Procedures

23

Validation of Allograft Bone ProcessingValidation of Allograft Bone Processing

Post Cleaning Residuals (mg/sq ft) Post Cleaning Residuals (mg/sq ft)

Lipids Bone Blood

Table 0.90/6.7 0.06/0.23 0.00/0.01

Bandsaw 1.6/17 0.05/0.38 0.00/0.01

MedClean 0.36/6.9 0.07/0.18 0.01/0.02

Cleaning Validation to Prevent Cross Contamination

1 validation of bone allograft processing: reducing risk of disease transmission via conventional...

Documents

bone tissue

bone formation

quantitative viral burden

boneextrapolate viral

type of tissue

risk of disease transmission

assessment of risk

multifunctional process