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Assay Qualification/Validation – a Reviewer’s Expectations

Sarah KennettDivision of Monoclonal AntibodiesOffice of Biotechnology Products

OPS/CDER/FDA

October 20, 2010

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DisclaimerThe views and opinions expressed here are my own and should not be used in place of regulations, published FDA guidances or discussions with the Agency.

These views reflect CDER/OPS/OBP discussions.

This talk is focused on analytical assays used to assess drug substance, drug product, and in-process materials.

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Overview

Why this subject?

What does FDA say –

officially?

What do we OBP product reviewers mean by “qualification”

and

“validation”?

Some expectations

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Person X: Someone told me assays need to be validated to start Phase 2 studies.

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Me: No, unless there is a scientific reason, submission of assay validation isn’t required until the BLA is submitted. However, you

need to be using qualified assays from the beginning. If the assays you’re using during later phases of clinical development can’t be validated, you might be in trouble regarding setting of acceptance criteria and dosing/efficacy assessment.

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X: So, we need to show you validated assays by Phase 3.•

Me: Uhh, no, not exactly. Formal validation studies CAN be performed as early as you want, but with a few exceptions, the REQUIREMENT regarding timing of the original validation {exceptions include assays critical for safety!}

is that it be

completed prior to submission of the BLA to be included in the submission. For phase 3, you probably need to be using assays that can be validated, though, so they need to at least be well qualified.

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X:…•

Me:…

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What does FDA say regarding BLA/NDA stage assays?

The accuracy, sensitivity, specificity, and reproducibility of test methods employed by the firm shall be established and documented. Such validation

and documentation may be

accomplished in accordance with …21 CFR 211.165(e) (Testing and release

for distribution)

At the time the application is submitted to the regulatory authorities, applicants should have validated

the analytical

procedures uses in the specifications.ICH Q6B

Analytical methods should be validated…ICH Q7

The stability

program shall include…reliable, meaningful, and specific test methods.

21 CFR 211.166(a)(3)

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Although in each phase of the investigation sufficient information

is required to assure the proper identification,

quality, purity, and strength

of the investigational drug, the amount of information needed to make that assurance will vary with each phase

of the investigation, the proposed

duration of the investigation, the dosage form, and the amount of information otherwise available.21 CFR 312.23(a)(7)(i)

The {IND} submission is required to contain:…the acceptable limits and analytical methods used to assure the identity, strength, quality, and purity of the drug substance [drug product]…21 CFR 312.23(a)(7)(iv)(a) [21 CFR 312.23(a)(7)(iv)(b)]

What does FDA say regarding IND stage assays?

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One of the clearest statements FDA makes regarding a requirement for ASSAY validation

at

the IND stage is in the PROCESS validation guidance?

While validated analytical methods

are not required during product-

and process-development activities,

methods should be scientifically sound (e.g., specific, sensitive, and accurate), suitable, and reliable for the specified purpose.

Guidance for Industry: Process Validation: General Principles and Practices. FDA/CDER, CBER, CVM. 2008.

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Validation vs. Qualification Are we speaking the same language?

Process validation

is defined as the collection and evaluation of data, from the process design stage throughout production, which establishes scientific evidence that a process is capable of consistently delivering quality products.

Process validation involves a series of activities taking place over the lifecycle of the product and process. This guidance describes the process validation activities in three stages.

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Stage 1 –

Process Design: The commercial process is defined during this stage based on knowledge gained through development and scale-up activities.

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Stage 2 –

Process Qualification: During this stage, the process design is confirmed

as being capable of reproducible commercial manufacturing.•

Stage 3 –

Continued Process Verification: Ongoing assurance is gained during routine production that the process remains in a state of

control.

Guidance for Industry: Process Validation: General Principles and Practices. FDA/CDER, CBER, CVM. 2008.

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Validation vs. Qualification Are we speaking the same language?

Lifecycle

Stage 1 –

Process Design: The commercial process is defined during this stage based on knowledge gained through development and scale-up activities.

Stage 2 –

Process Qualification: During this stage, the process design is confirmed

as being capable of

reproducible commercial manufacturing. Stage 3 –

Continued Process Verification: Ongoing

assurance is gained during routine production that the process remains in a state of control.

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Validation vs. Qualification Are we speaking the same language?

Lifecycle (borrowing from Process Validation)

Stage 1 –

Assay Design: The assay is defined during this stage based on knowledge gained through development activities.

Stage 2 –

Assay Qualification: During this stage, the assay design is confirmed

as being capable of producing

reproducible results suitable for the specified purpose.

Stage 3 –

Continued Assay Verification: Ongoing assurance is gained during routine use that the assay remains in a state of control.

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Validation vs. Qualification Are we speaking the same language?

For a bioanalytical

[BA, BE, PK] method to be considered valid, specific acceptance criteria should be set in advance and achieved for accuracy and precision for the validation of QC samples over the range of the standards.

The validity of an analytical method should be established and verified by laboratory studies, and documentation of successful completion of such studies should be provided in the assay validation report.

Guidance for Industry: Bioanalytical Method Validation. FDA/CDER, CVM. 2001.

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Validation vs. Qualification Are we speaking the same language?

Qualification: The assay design is confirmed as being capable of producing reproducible results suitable for the specified purpose. Test how the assay performs and decide if that performance is suitable for that point in development. If it isn’t good enough, change the assay.Work in progress, but scientifically sound and suitable for its purpose.

Validation: The assay is tested against specific acceptance criteria set in advance to verify that the performance characteristics (those listed in ICH Q2(R1) and potentially others, depending on

the assay and the product) of the final method are suitable and reliable for the intended applications. Documentation of successful completion of such studies should be provided in an assay validation report.Final product, documented to meet performance acceptance criteria.

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Validation vs. Qualification Are we speaking the same language?

Lifecycle (borrowing from Process Validation)

Stage 1 –

Assay Design: The assay is defined during this stage based on knowledge gained through development activities.

Stage 2 –

Assay Qualification: During this stage, the assay design is confirmed as being capable of producing reproducible results suitable for the specified purpose. Scientifically sound work in

progress.

Stage 2 ½

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Formal Assay Validation Study: The assay is tested against specific acceptance criteria set to verify that the performance characteristics of the final method are suitable and

reliable for the intended applications.

Stage 3 –

Continued Assay Verification: Ongoing assurance is gained during routine production that the assay remains in a state of control. (system suitability, assay suitability, trending of results, OOS, etc.)

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Early DevelopmentSubmissions need to contain enough information

for reviewers to determine whether or not the methods are scientifically sound (e.g., specific, sensitive, and accurate), suitable, and reliable for the specified purpose.

The specified purpose is to provide sufficient information to assure the proper identification, quality, purity, and strength. The assay needs to be sufficiently developed to ensure that acceptance criteria are meaningful.

What does this really mean?

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Early DevelopmentReviewers need enough information to make these

assessments.How much information is needed will be product

and assay dependent.

less moreconcentration

UV spectroscopy

CE methods

potency

cell based assay

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Early DevelopmentReviewers need enough information to make these

assessments.How much information is needed will be product

and assay dependent.

less morecIEF

Charge variants of an IgG1

cIEF

Antibody drug conjugatedrug:antibody ratio

cIEF

Charge variants of a Fc fusion protein

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Early DevelopmentReviewers need enough information to make these

assessments.How much information is needed will be product and

assay dependent.

cIEF for identity example: If the product is a second generation product, a sponsor may need to include some specificity data in the IND original submission.

The data themselves can sometimes provide information regarding the suitability/reliability of the assay.

(don’t forget about system suitability, equipment qualification, critical reagent variability)

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Later DevelopmentSubmissions need to contain enough information

for reviewers to determine whether or not the methods are scientifically sound (e.g., specific, sensitive, and accurate), suitable, and reliable for the specified purpose.

The specified purpose is to provide sufficient information to assure the proper identification, quality, purity, and strength. The assay needs to be sufficiently developed to ensure that acceptance criteria are meaningful.

What does this really mean?

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Later DevelopmentSubmissions need to contain enough information

for reviewers to determine whether or not the methods are scientifically sound (e.g., specific, sensitive, and accurate), suitable, and reliable for the specified purpose.

The specified purpose is to provide sufficient information to assure the proper identification, quality, purity, and strength. The assay needs to be sufficiently developed to ensure that acceptance criteria are meaningful.

What does this really mean?

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Later DevelopmentNeed to be able to correlate commercial product

with the clinical study material.

Efficacy data and safety data from clinical studies are associated with quality attributes.

There is a sort of link between the safety and efficacy data and the acceptance criteria set at licensure.

Specification acceptance criteria are initially set using historic data from clinical lots with an emphasis on the product used in pivotal studies.The historic data need to be “correct.”

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Later DevelopmentLOQ (or LOD), range, precision, etc. may be

extremely important, especially if a safety risk or dosing issue is involved.e.g. an impurity that is detected using a CE method

If the assay that was in place during testing of late stage clinical material cannot be validated, you may have difficulty setting acceptance criteria.

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BLA/NDA submissionThe application for licensure/approval should include a validation

report for each non-compendial assay (suitability verification/conditions of actual use) used for lot release and stability. Characterization assays used during the generation of

new reference material should also be validated, as should additional characterization assays depending on their intended use.

The studies performed should include the appropriate performance parameters from those listed in ICH Q2(R1) and potentially others, depending on the assay and the product) .

Information included in/with the report should include the study protocols with the pre-defined acceptance criteria and enough

information regarding the assay protocol and prior characterization/qualification to allow for an assessment of the

validation protocol.

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Post-licensure ChangesModification of any particular test method or

manufacturing process or the conditions under which it is conducted…shall be permitted only under the following conditionsThe applicant presents evidence…demonstrating that

the modification will provide assurances of the safety, purity, potency, and effectiveness of the biological product equal to or greater than the assurances provided by the method or process specified…

21 CFR 610.9(a)

To us (FDA), this means re-validation (sometimes partial revalidation) is likely to be necessary.

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Post-licensure ChangesRevalidation may be necessary for

Changes in the synthesis of the drug substanceChanges in the composition of the finished productChanges in the analytical procedure

The degree of revalidation required depends on the nature of the changes.

Certain other changes may require revalidation as well.

ICH Q2 (R1)

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Method TransferTransfer of validated analytical methods from the originating laboratory to a

new laboratoryTo ensure comparability in the validation characteristics between laboratoriesTo prevent and/or detect changes in data trend

To improve transfer success, historical data from the originating site can be used to identify the greatest causes of variance in an assay.

Assess a subset of validation parameters with pre-defined acceptance criteriaUsing Equivalence Testing (Precision and Accuracy)Using Key attributes

(Precision, LOD/LOQ, Accuracy, Identity, Linearity)

Typical Transfer should include:More than one lot of material (Reference Standards, Samples at extremes of

the established acceptable limits, Stress samples)

Testing of the same samples at both sites At least one analyst at the originating laboratory and multiple analysts in the

receiving laboratory

(From Kathy Lee talk “Analytical Method Transfer”)

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References21 CFR 211, 21 CFR 312, 21 CFR 610Guidance for Industry: Bioanalytical Method Validation. FDA/CDER,

CVM. 2001. Guidance for Industry: Process Validation: General Principles and

Practices. FDA/CDER, CBER, CVM. 2008.

ICH Q2(R1). Validation of Analytical Procedures: Text and Methodology. 2005.

ICH Q6B. Test Procedures and Acceptance Criteria for Biotechnological/Biological Products. 1999.

ICH Q7. Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients. 2000.

Other interesting reading:Nadine Ritter, et al. What is Test Method Qualification: Proceedings of

the WCBP CMC Strategy Forum, 24 July 2003. BioProcess International 32-46. 2004.