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Establishing Comparability with Process and Manufacturing Changes for Recombinant Vaccine: A case study of HPV Vaccine

Dicky Abraham Global Vaccine and Biologics Commercialization

Merck & Co., Inc

WCBP, Jan 2015

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Outline

• HPV and HPV Vaccine • Importance of characterization • Characterization of Gardasil® • Comparability matrix • Comparability Assessment for facility scale-up • Conclusions

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Rationale For An HPV Vaccine

• Human Papillomavirus (HPV) infection causes cervical and anal cancers, and genital warts.

• Pap smear has reduced cervical cancer rates, but it has significant drawbacks: – repeat testing required – limited sensitivity & specificity – psychosocial impact of a “pre-cancer” diagnosis – high costs – not feasible in the developing world

• A vaccine to prevent infection with common pathogenic HPV types is a major advance in anogenital cancer control.

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Immunologic Basis For Candidate HPV Vaccines

• Vaccine candidates have been evaluated in animal models of papillomavirus infection.

• L1 VLP Vaccines

– L1 HPV major capsid protein self-assembles into virus-like particles (VLPs)

– In preclinical studies using species-specific VLPs:

• vaccination protection against infection / disease

• efficacy associated with development of neutralizing antibodies

• transfer of serum from vaccinated to unvaccinated animals transfers protection

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Clone L1 Gene for the Capsid Protein for Each HPV Type

HPV Coat (Capsid) Proteins Expressed in Yeast

HPV Virion infectious

HPV 6, 11 - genital warts HPV 16, 18 - cervical cancer

Intracellular expression in S. cerevisiae

HPV Virus Like Particle

non-infectious vaccine

Key expression features: - tightly-regulated promoter - common host strain - common vector

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GARDASIL Merck’s Quadrivalent HPV Vaccine

• Quadrivalent HPV (Types 6, 11, 16, 18) L1 virus-like particle

(VLP) vaccine-approved in 2006

• VLPs manufactured in yeast

• Highly purified VLPs

• Well Characterized

• Approved world-wide

Structural Model of HPV VLP

Virus-Like Particle (~20,000 kDa)

72 Capsomere

L1 Capsomere (~280 kDa)

5 x L1

(Atomic force microscopy image of a single VLP)

L1 protein (55 or 57 kDa)

(Crystal structure coordinates courtesy of Prof. S. C. Harrison,

Harvard University)

~ 3 nm ~ 10 nm ~ 60 nm

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• Historically for complex vaccines and biologics “The Process Defines the Product”

• Modern vaccines are amenable to modern biochemical characterization techniques

• Requirement to demonstrate that we understand our product (CTD Sections S3.1, S3.2, S4 & P5).

• Release, Process Characterization & Comparability

• Rational bridge to clinical data

• Functional potency test

Why Characterize a Vaccine?

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HPV VLP is Very Complex

HPV Virus Like Particle

IgG Immunoglobin (Therapeutic mAb)

Zocor®

Aspirin

~150X

~150X

Method – Structure Link

MBAP DLS, DSC, IVRP &

IC50

3° and 4° Structure DSC, DLS, IC50,

Relative Antigenicity, Free Thiols in Native Form & L1-

Oligomer

2° Structure CD & FT-IR

1° Structure Mass Spec,

Purity, Integrity, Deamidation, & Free Thiols in Denatured

Form

Amino Acid Sequence

Assembly

Disassembly

Adsorption α-Helix

β-Sheet

Aluminum Adjuvant

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Primary Structure

• Mass spectrometry • SDS –PAGE • Deamidation • Free Thiols

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Secondary Structure

• Circular Dichroism • Fourier Transform IR Spectroscopy

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Tertiary and Quaternary Structure

• Differential Scanning Calorimetry • Dynamic Light Scattering • Relative antigenicity • Atomic Force Microscopy • Cryo EM • Potency (in Vitro Relative Potency)

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Summary Product Characterization

• Meets Regulatory Expectations

• Supports modern in vitro potency tests

• Focused testing (rather than testing to infinity) is desired.

• Provides data base to observe changes in product over time

• Supports development

• Supports post licensure process changes

• Analytical Matrix Approach to comparability based on identifiable & relevant changes.

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ICH Quidelines (Q5E) • Comparabillity goal is to ensure the quality, safety and efficacy of

drug product produced by a changed manufacturing process: – Achieved through collection and evaluation of the relevant data

– Affirm there is NO adverse impact on the drug product due to the manufacturing process changes.

• Comparability does not necessarily mean that the quality attributes of the pre-change and post-change product are identical, – But highly similar

– Existing knowledge is sufficiently predictive to ensure that any differences in quality attributes have no adverse impact upon safety or efficacy of the drug product.

• Comparability can be based on a combination of analytical testing, biological assays, and, in some cases, nonclinical and clinical data. – Aassurance of comparability through analytical studies alone,

• Non-clinical or clinical studies are not warranted-where the relationship between specific quality attributes and safety and efficacy has been established.

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Comparability for a Well Characterized Vaccine

• Distinguishes difference in final vaccine structure

• Sensitive to process • Distinguishes intermediate from final product • Essential data base for future process changes • Comparability Plans and Protocols

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• Used for “specified” or “well-characterized” biologic products. – “Historical” Comparability

– Therapeutic / Clinical Equivalence

• Fundamental limitation: can’t always state if a change matters. – Focused testing (rather than testing to infinity) is desired.

– (Analytical) Matrix Approach to comparability based on identifiable & relevant changes (more case-by-case).

• “Characterization” vs “Comparability” Testing

Comparability Plan

• Monitor clinically-relevant structural features that are desirable properties of the product. • Emphasis on release assays & epitope structure (conformation) during manufacture & storage.

Analytical Matrix for Comparability

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Method

Release - Potency

Release – Purity & Integrity

IC50

Rel. Antigen.

DSC

DLS

Free Thiols

Oligomer

Deamidation

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HPV VLP Manufacturing Process

Jansen et al. (Merck & Co.) US Patent 5,888,516, 1999; Cook et al., Protein Exp. Purif., 17, 477, 1999

Release intracellular HPV VLPs

Digest DNA/RNA

Clarify yeast lysate

Remove bulk yeast impurities

Remove residual impurities and buffer exchange.

Reduce nucleic acid and aggregates

Produce in recombinant yeast

This image cannot currently be displayed.

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Manufacturing Change: Facility Scale-Up

• A small scale purification facility was used to produce clinical, process validation and launch drug substance lots

• Scale up facility constructed to meet projected market demand

• Process for new facility was scaled up – Required targeted changes to manage larger production

scale

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Process Comparability • Limited process changes with new facility • In-process inputs & outputs to demonstrate new

facility process is comparable to launch facility Critical Process Parameters (CPPs) and Critical Quality

Attributes (CQAs) Key Operating Parameters (KOPs) and Key Process

Attributes (KPAs)

• Process characteristics to demonstrate comparability to launch facility process characteristics Qualitative comparisons of chromatography profiles, pH

profiles, and impurity clearance profiles

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Process Peformance

• For each parameter performance was evaluated against acceptance limit and historical performance (launch facility ranges)

• Excursions were investigated

Process Step Attribute Launch Facility Range

Lot 1 Lot 2 Lot 3

VLP Release Parameter 1 95 – 98 100 95 95

VLP Capture and Purification

Parameter 2 69 - 74 87 80 78

Parameter 3 1.5 – 2.9 2.9 2.9 2.9

Polishing Purification

Parameter 4 96 - 98 98 96 97

Parameter 5 0.5 – 1.7 1.4 1.3 1.3

VLP Disassembly Parameter 6 98 – 99 99 99 99 VLP Reassembly Cross linking

Parameter 7 99 – 100% 100 100 100 Parameter 8 11 – 13 11 13 11 Parameter 9 81 – 98 98 86 93

Buffer Exchange Parameter 10 717 - 928 856 777 875

Parameter 11 106 - 114 107 106 103

Sterile Filtration Parameter 12 > 100 97 102 108

Alum Adsorption Parameter 13 300 - 322 338 317 320

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Example: Impurity clearance

• Comparable clearance profile for all impurities and process residuals

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Summary: Process Perfomance • In-process outputs, Critical Quality Attributes, Key

Process Attributes demonstrated comparability to launch facility

• Qualitative comparison demonstrated process is comparable to launch facility Chromatography profiles pH profiles Impurity and process residual clearance profiles

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Product Comparability Overview

Analytical Measures

• Product Characterization • Impurities • Stability

Mfg Database • Represent manufacturing diversity • Analytical variability

Expected Results

• Acceptance Criteria (Primary Limit) • Alert Limit (Secondary Limit)

Process Change

Comparable Meets acceptance and alert limits

Not Comparable

Fails acceptance criteria

Investigate

Investigation includes: Weighting of parameter Evaluate data from all lots Clinical Experience Results from other parameters

Meets acceptance Limits but outside Alert limits

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Developing Limits from our database

Limits prospectively established to define potential deviations from comparability Provides rigor and credibility

Two types of Limits

Acceptance Limits = deviations generally means failure to demonstrate comparability Alert levels = deviations results in investigation, but not deemed a failure a priori Limits/Levels must be sufficiently rigorous but not so tight as to cause “nuisance alarms”

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Analytical Comparability: Drug Substance

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Investigation of Excursions • T6 Potency (IVRP) Investigation: Alert Level excursion Lot #3

• Assay: No atypicals found in assay run

• IC50 & Relative Antigenicity assays (orthogonal immunoassays) had expected results

• Stability data showed expected IVRP

Conclusion: assay variability, lot is comparable

• T16 Free Thiols: Alert Level excursion Lot #3

• Assay measures non-crosslinked SH molecules, result can suggest particle may be malformed and/or unstable

• Stability evaluations showed no change in stability profile

• Particle size and level of monomer consistent with other lots

Conclusion: excursion does not have an impact on product quality or stability, lot is comparable

• Differential Scanning Calorimetry (DSC): all lots

• Limited number of runs used to set alert limit

• Run to run variability not represented in alert limits

• Samples from Phase III lots run concurrently with new facility lots showed similar alert limit excursion

Conclusion: lots are comparable

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Conclusion

• A modestly scaled purification facility was used to supply Phase III and launch material for GARDASIL®

• A larger facility was required to meet the expected demand for the product

• A key component of the licensure for the new facility was the demonstration of comparability of drug substance and drug product made in the two facilities

• The comparability assessment shows the product made in the new facility is comparable to that from the launch facility

• Merck leveraged comparability to accelerate licensure of larger-scale facility, providing world-wide supply ASAP

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A. Acosta R. Capen J. Bendas J. Dashnau P. DePhillips P. Desai M. Kosinski M. MacNeil W. Muthoga D. Opalka

B. Oswald R. Peluso C. Potter (Scripps) R. Sitrin J. Robinson R. Rustandi S. Sagar C. Schultz A. Sturgess

Acknowledgments

G. Takle V. Towne Y. Wang M. Washabaugh D. Wohlpart Q. Zhao