validation of production processes for vaccines for who ... · page 2 of 37 this guidance document...

Validation of Production Processes for

Vaccines for WHO Prequalification-

Compliance Expectations

A note for guidance for the manufacture of prequalified vaccines

for supply to United Nations agencies

July, 2013

Vaccine Quality and Regulations (VQR)

Essential Medicines and Health Products

World Health Organization (WHO), Geneva, Switzerland

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This guidance document “Validation of Production Processes for Vaccines for WHO

Prequalification - Compliance Expectations” is one of a series developed by

WHO/EMP/VQR team upon request from the manufacturers’ members of the Developing

Countries Vaccine Manufacturers Network (DCVMN), with funds from USAID.

A set of priority topics has been identified by vaccine manufacturers for WHO to provide

guidance on the expectations from the vaccine prequalification programme.

The guidance document is targeted primarily at manufacturers new to the prequalification

process of vaccines and who require guidance on the level of detail needed for process validation

activities. It may also be a useful guide to National Regulatory Authorities (NRAs) in vaccine

producing countries for the purpose of regulatory inspection.

These are not official WHO documents but rather notes for guidance on expected standards to be

met for the prequalification of vaccines. Based on WHO recommended requirements, these

documents provide further explanations with examples in order to facilitate implementation.

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Table of Contents

Page

1. Introduction 4

2. Purpose 4

3. Scope 5

4. Lifecycle Approach in Process Validation: from R&D through

clinical trials to commercial scale

5

4.1. Validation risk assessment – What needs to be validated and when 7

5. Process Validation Stages 8

5.1. Validation Stage I 8

5.2. Validation Stage II 18

5.3. Validation Stage III 29

5.4 Revalidation 30

5.5 Validation Studies and the WHO Pre-Qualification process

Expectations 31

Appendix 1 33

Glossary 34

References 35

Acknowledgements 37

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1. Introduction

Companies should validate their manufacturing processes by acquiring sufficient knowledge

about the characteristics of the product to be manufactured, and by having an appropriate

production process control prior to the manufacturing of the first commercial batch. This

approach assures consistency of the production process and demonstrates the capability of the

commercial manufacturing process to give a high degree of assurance of obtaining medicinal

products meeting the required quality attributes of safety, purity, and efficacy on a continued

basis. “Process validation (PV) is the collection and evaluation of data, from the process design

stage through commercial production, which establishes scientific evidence that a manufacturing

process is capable of consistently delivering quality products. Process validation is required by

current Good Manufacturing Practice (cGMP) as an essential element in the assurance of drug

quality”(22). Process validation is also typically defined as “documented evidence which

provides a high degree of assurance that a specific process will consistently result in a product

that meets its predetermined specifications and quality attributes” (1).

Product quality requires full compliance with WHO GMP requirements, including a meaningful

process validation program based on the assumption that “quality cannot be adequately assured

merely by in-process and finished-product inspection and testing” (2)

“Validation offers assurance that a process is reasonably protected against sources of variability

that could affect production output, cause supply problems, and negatively affect public

health”.(2)

PV also proves that in spite of changes in operational parameters through the necessary

scale up of the production process, including new facilities and equipment, the product

characteristics will not vary.

This guidance document considers process validation as part of the product’s life cycle as

recommended by the International Conference on Harmonization (ICH) in Q8 Pharmaceutical

Development and Q10 Pharmaceutical Quality System, and is in line with the requirements of

both FDA and EU.

2. Purpose

This guidance document is aimed at presenting current WHO main expectations towards process

validation, and at supporting effective and timely implementation of validation programs as they

relate to vaccine manufacturing. It is intended to assist manufacturers in assuring reliable,

reproducible and robust manufacturing processes before the first commercial batch is produced,

and insure that process changes will result in a product with equal or superior quality

characteristics.

This document is based on WHO GMP regulations, as well as other internationally recognized

GMP regulations, guidelines and publications, in addition to incorporating the experience of

experts and auditors in the field.

This note for guidance also provides manufacturers with non-binding information concerning the

criteria currently used by WHO for the assessment of prequalified human vaccines.

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3. Scope

This guidance provides an updated general view of relevant points to consider related to process

validation of vaccine and biopharmaceutical production processes, which apply to all

manufacturing stages from seed or cell culture to final drug product. This guidance primarily

applies to new products although legacy products may also benefit from adopting such an

approach. The following are some manufacturing processes requiring validation which are

covered in this document:

Fermentation

Harvesting

Purification

Viral Clearance

Inactivation

Blending & Formulation

Lyophilization

Other critical manufacturing processes are briefly described, considering there is extensive

guidance on them, including:

Cleaning of product contact equipment

Sanitization of areas

Depyrogenation

Sterilization

Aseptic Filling or encapsulation process of Final Product

Utilities, facility and equipment qualification, analytical assay validation, and validation of

computerized systems are referenced but not covered in this document.

4. Lifecycle Approach in Process Validation: from R&D through clinical

trials to commercial scale

Lifecycle approach is the recommended approach to achieve quality in pharmaceutical products

as it is oriented to “facilitating innovation and continual improvement, as well as to strengthen

the link between pharmaceutical development and manufacturing” (8).

A central concept in this approach is that “process validation should not be viewed as a one-time

event but rather as an activity that spans the product lifecycle linking process development,

validation of commercial manufacturing process, and its maintenance during routine commercial

production”(22). Process development, commercial manufacturing capabilities, and the quality

system must be integrated in order to achieve effective and compliant commercial operations, as

shown in Diagram 1. This approach implies that process validation starts before consistency lots

are produced, and continues during the commercial stage during which the knowledge of the

product and process will continue to increase.

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Consistency lots are manufactured to prove that the process is under control, and those batches

produced can only be released if they all meet specifications and after the Process Validation

study is completed and approved. “The PV Lifecycle concept links product, process, the

qualification of the commercial manufacturing processes and maintenance of the commercial

production process in a coordinated effort”(2). This overall lifecycle process normally follows

sequential phases including PV activities which typically may be performed in development

phases, as it will be described in this document. Prospective Validation is expected when

planning the validation effort in line with a Lifecycle Approach.

Process validation requires an interdisciplinary approach that incorporates expertise from a

variety of disciplines (e.g., Engineering, Chemistry, Microbiology, statistics, manufacturing, and

Quality Assurance), and demands a significant planning effort with full support by upper

management. The Quality and Regulatory organizational units shall be part of the product cross

functional team from the beginning of the process validation study design. “The Quality Unit

will provide the necessary oversight and approval of process validation studies that are required

to be performed under GMP´s, including specific validation activities performed at certain stages

of development” (22).

Diagram 1

Research & Development

Clinical Trial Ph-3

Acceptable Range

Characterization Range

Development

Design

Product

Knowledge

Continual Improvement

Commercial

Manufacturing

Acceptable Range

Efficacy

Safety

Operating Range

Acceptable Range

V A

L

I

D A

T

I O

N

V

A

L

I

D A

T

I

O

N

QUALITY

V

A

L

I

D

A

T

I

O

N

P

R

O

C

E

S

S

V

A

L

I

D

A

T

I

O

N

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4.1. Validation risk assessment – What needs to be validated and when

Quality Risk Management (QRM) should be used along the lifecycle of the product through the

different validation stages. All product attributes and operational parameters should be evaluated

in terms of their roles in the process and impact on the product or in-process material, and re-

evaluated as new information becomes available. This will contribute to identify critical

operational parameters. Therefore, PV activities may focus on those processes which pose the

greatest risk. The degree of control over those attributes or parameters should be commensurate

with their risk to the process and process output. In other words, “a higher degree of control is

appropriate for attributes or parameters that pose a higher risk”. (2)

ICH Q9 Quality risk management recommends several tools (e.g., Failure Modes and Effects

Analysis FMEA), which may be used in product development and for designing the required

validation studies based on analysis of potential severity and likelihood of failures.

ICH Q9 II.6 (Quality Risk Management as Part of Production Validation), states that Quality

Risk Management (QRM) is recommended to identify the scope and extent of verification,

qualification and validation activities (e.g., analytical methods, processes, equipment, and

cleaning methods)”. (18)

HACCP (Hazard Analysis Critical Control Point) methodology may also be used for

identification and management of identified risks associated with the process, including

microbiological and cross contamination aspects. QRM is a recommended tool to define variable

criticality and required controls in manufacturing processes, and to justify which variables are

going to be focused during validation studies which have a high impact on the product if they

fail. Every product and associated processes poses its own set of risks which need to be

identified as part of the product development efforts. For example, some of the factors that may

affect the safety, identity, strength, quality and purity of a product may be bioburden and

endotoxin levels, glycoform distribution (e.g., cell culture and fermentation), product

homogeneity (e.g., mixing). Product development reports (PDR) and tech transfer packages

should identify these risks which need to be addressed as part of validation studies, as

exemplified below:

How does the product, at its stage in manufacture, interact with materials? Does it

adsorb, clump, or precipitate?

How does the product interact with manufacturing processes? Does it shear, oxidize,

reduce, break S-bonds, combine with other anions in the formulation to make new (and

unstable) salts, or precipitate?

How does the product interact with the equipment? Does it rust, may gaskets leak, or do

the inlets and outlets get obstructed?

How does my seed replicate under certain conditions? Does it mutate? Transpose genetic

elements with other viruses or plasmids? Is there a selection pressure where just one

clone expands, and the others die out?

How does lyophilisation affect potency? Is viability reduced if freezing takes place over

a long time? If there is too much / too little moisture, is the stability at the end of shelf

life adequate? Is the holding time established once freeze-dried product is reconstituted?

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Note: For further in depth reading refer to PDA´s Process Validation: A Lifecycle Approach; Application

of Risk Management (22).

5. Process Validation Stages

Current recognized guidance documents have described process validation studies as a

cumulative effort divided in three stages in line with the Lifecycle approach (e.g., FDA, PDA

guidance documents). The degree and depth of the validation studies required will vary

depending on the product (i.e., new products, or well-known products), as shown in Appendix 1:

Outline of R&D, product development and commercial production in the context of Process

Validation.

5.1. Validation Stage I

A first validation stage (i.e., FDA´s Process Design stage) gathers studies performed

concurrently with the product development phases, generating a basic information package

which should be documented (e.g., technological transfer package). Product research and

development should give the best possible design space to the manufacturing operation plant

where validation will take place. Quality by Design may be defined as “a systematic approach to

development that begins with predefined objectives and emphasizes product and process

understanding and process control, based on sound science and quality risk management” (ICH

Q8). During development, R&D gathers experimental/technical data to establish parameter

criticality through definition of Proven Acceptable Ranges (PARs) and/or design space. Those

PARs are then used in the following validation stage to define commercial operational settings

and ranges at which the process will operate. The knowledge gained at the development stage

will be the basis for designing the manufacturing process including relevant information which

will eventually lead to routine control tests and specifications, such as pH & Optical density

during fermentation process, temperature during conjugation process, temperature during

detoxification process, etc. It should also take into consideration the choice of drug product

elements, e.g., properties of the drug substance, excipients, and container closure system, and, if

possible, the knowledge gained from the development of similar drug product(s).

The following are some typical process development activities and typical process validation

activities and deliverables at this stage for vaccine manufacturing which should have been

completed before initiation of commercial scale validation studies (i.e., PV Stage II):

Host cell system/cell line selection

Cell tissue, and seed banks (Master and Working Stock)

Cell culture/fermentation process development

Harvest process development

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Inactivation/detoxification

Purification process

Formulation development

Analytical method development

Pharmacokinetic/toxicology studies

In-process controls (in-process tests and broad operational parameters)

Process scale up

Process characterization

5.1.1. Process Description

The validation study typically contains a summarized description of the manufacturing process,

including each manufacturing step, attributes to be met, and the associated process operational

parameters. Flowcharts are generally used for this purpose. The justification of the selection of

these parameters is usually included in the development information package (e.g., operational

parameters of upstream manufacturing phase could be characteristics of the inoculum which

would influence cell culture in-process attributes and harvest quality indicators). They are

usually associated with critical product quality attributes that affect product safety, quality and

purity. Later, during PV Stage II, it shall be demonstrated that these parameters and attributes are

consistently met at full scale.

5.1.2. Process Characterization

Process Characterization studies consist of “a set of documented laboratory studies in which

operational parameters are purposely varied to determine their effect on product quality attributes

and process performance”(1)

. The goal of process characterization studies is to challenge and

verify that the operational parameters consistently lead to product meeting quality characteristics

within a set range of limits. Considering that acceptable ranges (i.e., proven acceptance ranges or

PAR) cannot be determined for all operating parameters, risk assessment is often used to identify

parameters which need to be evaluated in order to demonstrate that the acceptable range is wider

than the operating range. An acceptable range is known as Normal Operating Range: “A defined

range, within (or equal to) the Proven Acceptable Range, specified in the manufacturing

instructions as the target and range at which a process parameter is controlled, while producing

unit operation material or final product meeting release criteria and critical quality attributes”

(23). Examples of operational parameters are given in Table 1.

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Table 1. Operational Parameters Summary for Cell Culture and Tetanus Toxin Production

Process Stage

Process / Operational

Parameter

Unit Parameter

Type Set Point

Operating

Range

Inoculation

Cell density (a) Cell/ml Critical operation 3 x 106 2 - 4 x 10

6

Production (Fermenter)

Vibration speed (b) Hz or % Critical operation 50 50 ±5

Airflow (c) SLPM Critical Operation 30 30 ±5

(a) Low cell density at inoculation stage will prevent growth to be started.

(b) Excessive agitation will prevent cells (e.g.: Vero cells) to attach onto the micro carrier beads, causing

reduced or no cell growth.

(c) Low intake of air throughput in the headspace of Tetanus fermentation would not sweep out volatile

compounds which may be toxic to cells. (SLPM: Standard Liter per Minute)

Note: An operational parameter could be critical in one system or process, and not critical in another.

Process characterization studies are normally summarized including a list of the operational

parameters and their justification, acceptable ranges, determination of criticality, etc., as well as

any other pertinent information from the study.

For illustration purposes of a process characterization study, the development of a culture

medium is given:

Based on a graded concentration of carbon source (e.g. different type of sugars) or nitrogen

source (e.g. amino acids) and from the growth obtained, the optimal concentration of the culture

medium can be determined. By repeating the experiment with all other ingredients such as

growth factors, the final composition of the culture media giving preferably long steady state

optimal growth, acceptable low toxicity, good stability, etc., may be determined. For example,

the optimization of culture media assures high diphtheria toxin antigen yields; contrary to this,

higher than optimum concentration of carbon source could result in high cell count but might

prevent production of the diphtheria toxin.

5.1.3. Raw Materials / Starting Materials

Production of a vaccine whether by fermentation, cultivation, isolation, or synthesis, requires

starting materials including culture media, buffers, serum (e.g.: foetal bovine serum, human

serum albumin), trypsin, amino acids and other chemicals, reagents such as monoclonal

antibodies, enzymes, proteins used in purification processes, and pharmaceutical grade / process

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water (e.g.: Water for Injection or Purified Water). Starting materials such as culture media

should be described in the corresponding approved specification, and QC tested.

Materials used for manufacturing purposes should be traceable throughout the production

process and through the different stages from clinical material manufacturing to commercial

scale. A qualification program should be developed for materials, especially for non-compendia

grade materials, including qualification of new materials or sources and vendor audit

requirements.

5.1.4. Extractables and Leachables from Product-contact Surfaces

“All product–contact surfaces used in a manufacturing process have the possibility of leaching

extractables into the process stream”(1)

. Documented data from manufacturers and published

literature is expected to be considered in addition to any necessary study to prove there is no

undesirable interaction between the material and the product, thus demonstrating the safety and

chemical compatibility of the material used. Clarification and sterilization filters may require an

enhanced qualification as per published guidelines (16)

.

5.1.5. Seed Banks

Seed banks can be identified as bacterial or viral seeds shown to produce antigens with the

required immunogenic properties and an acceptable adverse event profile, providing stable and

consistent yields using the established replication and purification schemes, that when

formulated have an acceptable stability throughout shelf life. The qualification of seeds intended

for use in the manufacture of vaccines includes assessment of the history and general

characteristics, seed banking system, and characterization of the seed through quality-control

testing. The passage history and derivation history of viral seeds, including donor screening,

testing and donor medical history, should be also documented.

5.1.6. Cell Lines and Cell Banks

An approach similar to the mentioned above for seed banks needs to be applied to cell bank

system of cell lines derived from all sources. “Biological drug substances are derived from

cellular sources (such as primary cells or cell lines) that have the potential to influence

consistency of the manufacturing process and quality of the drug substance. Adequate

characterization of the starting cellular material is therefore necessary to monitor and control the

manufacturing process”.(1)

In the case of developing appropriate testing strategies for

adventitious agents, the susceptibility of the cell substrate to infection with viruses other than the

vaccine strain should be considered. For example, as the cell substrates used for the production

of licensed oral poliovirus vaccines (primary monkey kidney cells) are susceptible to

contamination with simian viruses, such as SV40 or herpes B virus, specific tests are required in

each lot (5)

. If expression construct is used as part of production seed or cells, they also need to be

characterized as part of the banking system from master seed to end of production

characterization. Various parameters such as its retention, stability and consistency, need to be

established.

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5.1.7. Analytical Methods

Analytical methods must be validated prior to initiation of process validation studies. In some

cases, process validation studies are designed to explore process characteristics in more depth

and detail than the studies applied during routine manufacturing, therefore, certain additional

assays could be used during the execution of process validation studies and these need to be

evaluated as well. The validation of analytical procedures is directed to analytical procedures

such as identification tests, quantitative tests for impurities' content, and active substance or

potency assays. Typical analytical validation characteristics which should be considered include:

specificity, sensitivity, linearity, range, accuracy, precision, detection limit, quantification limit,

robustness, and system suitability testing. Detailed guidance for the validation of analytical

methods is contained in ICH “Validation of Analytical Procedures Methodology” ICH Q2B (14)

.

The limits of detection and quantification, as well as assay precision in the same sample matrix

that will be tested during process validation, should be defined.

For validating an in vivo potency assay, consider the following example:

- Pertussis vaccine potency assay is a surrogate test as it has no direct relation to the clinical

efficacy of the vaccine. The potency assay is represented as a quantal parallel line assay

comparing the vaccine under test to a standard or reference vaccine which might have been

tested and found efficacious clinically. Groups of mice (appropriate number, age, weight, sex)

are immunized with appropriate dilutions of the test and standard vaccines. After 14 days, they

are intra-cerebrally challenged with live Bordetella pertussis, and at day 28 the number of

survived mice is recorded. To validate this complex system, the mouse strain used, the standard

vaccine, and the challenge strain should be well established, and clinically justified (details not

given here). Use of international, regional or national standards and or procedure also needs to be

considered for the purpose of harmonization and validity of the tests.

5.1.8. Validation of production Steps or Unit Operations

Vaccines can be produced from a variety of compounds: antigens used for vaccines, live

attenuated bacteria, viruses or parasites, inactivated (killed) whole organisms, crude fractions or

purified immunogens including those derived from recombinant DNA in a host cell, conjugates

formed by covalent linkage of components, synthetic antigens, and polynucleotides (such as the

plasmid DNA vaccines). It may also be a combination of antigens listed above (4).

Considering the complexity of this process, “certain studies such as stability of in-process

intermediates and process solution stability studies may be performed separately from full-scale

conformance lots”(1). To achieve this goal, process validation could be divided into validation of

individual related groups of operations or unit operations rather than considering the entire

process. These studies (based on individual validation protocols) may be performed at pilot scale

prior to the manufacturing of consistency lots of finished product, including for example

recommended lifetime, holding time, and acceptable ranges for step yields. In certain cases,

parameters established prior to commercial consistency lots can be confirmed by on-going

validation carried out per pre-established protocol during commercial manufacture, or during the

manufacturing of consistency lots at commercial scale (e.g. membranes and resins lifetime,

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holding times, inactivation and detoxification, purification yields, impurities clearance). As

recommended by FDA’s Process Validation guidance, “The extent to which some materials, such

as column resins or molecular filtration media, can be re-used without adversely affecting

product quality can be assessed in relevant laboratory studies. The usable lifetimes of such

materials should be confirmed by an ongoing PPQ (Process Performance Qualification)

protocol during commercial manufacture.”

The acceptable limits of this variability must be examined, and from these results, optimized

operating parameters chosen. Depending on the situation, controlled experiments (e.g., scale-

down processes) may provide the information needed to identify minimum and maximum

operating parameters.

5.1.8.1.Propagation

Propagation of culture (cell growth) consists of a series of steps and critical factors which need to

be considered as part of the validation studies, such as:

Propagation from retrieval of the working cell bank (WCB) to culture harvest;

Culture media used at each step, with details on preparation and sterilization

Inoculation and growth of initial and sub-cultures (volumes, time, temperature of incubation)

Culture transfers and precautions taken to control contamination

In-process testing which determines inoculation of the main culture system

In-process testing for absence of adventitious agents, including tests on culture cells, if

applicable

Main culture system including operating conditions and control parameters (e.g., temperature

of incubation, static vs. agitated, aerobic vs. anaerobic, culture vessels vs. fermentor, volume

of fermentor, or number and volume of culture vessels)

Parallel control cell cultures, if applicable, including number and volume of culture vessels

(cell factories).

5.1.8.2.Fermentation

Critical points-to-consider in the validation of the fermentation process include data which

demonstrate the efficiency of induction of antigen production. For this, a growth curve or tabular

representation of growth characteristics of the fermentation process and each propagation step of

seed preparation should be provided as a basis for validation activities based on historical

performance under specified conditions. “Validation is done with actual growth culture, and all

in-process tests are applied. Typical tests applied for fermentation of a culture to provide a

product normally include microscopic purity of the pre-culture, pH value of the medium before

sterilization, temperature and pH value of the culture during the fermentation process, and of

medium” (17). During the propagation fermentation steps the goal is to maintain a steady state of

the culture in the exponential growth phase, in order to minimize the lag phases between

individual propagation steps. All parameters that may influence the growth rate should be

monitored, and if required controlled, such as microscopic purity of the culture, oxygen

saturation, pH, temperature, speed of impeller, foam formation and, most importantly, the

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production of antigen. By analyzing the growth curves, off-gas (headspace analysis), and

fermentation parameters, the length of fermentation and the optimal harvest time and yield can

be determined. Likewise, in-process control IPC pass/fail limits (acceptance criteria) can be set.

Critical aspects of the fermentation process used for antigen production may include:

- volume of air flow through headspace of fermentor (e.g., in Tetanus toxin production)

- speed of the impeller at the fermentor culture of anchorage-dependent cell substrates

- antigen stability under the conditions of fermentation (e.g., pH higher than 7.4 in

Pertussis antigen production)

- live and dead cell ratio at trypsinization of cell cultures

5.1.8.3.Harvest

The harvest should be made at that growth/physiological state of the culture at which the highest

antigenic yield of high potency and low toxicity is expected. As the optimal harvest time or

period cannot be easily determined in many cases, surrogate harvesting criteria may be used such

as number of cell doublings during the culture period, cell counts or number of colony-forming

units, optical density of the culture, percentage of live cells, pH of culture, etc. At this stage, an

antigen is separated from the propagation system by precipitation, centrifugation, filtration, or

similar processes. The following operational parameters are typically monitored and considered

during process validation:

- Speed of chilling of the culture;

- Capacity/volume/speed and temperature of separation/centrifugation/cross flow filtration;

- Preservative added, if applicable;

- Final holding temperature;

- Volume of inactivating/detoxifying agent, holding time and temperature in the fermentor,

in case inactivation/detoxification is done during harvesting.

The boundary between product development and process validation may vary in order to

determine the harvest time. A simple approach is to provide a tabulation on fermentation

parameters as well as yield, purity, and viability (if applicable) of the crude harvest, based on

historical performance with the corresponding potency and toxicity values. The optimal period of

harvesting is established when the IPC tests are within the acceptance limits. The duration of

harvesting time may also be critical in those cases in which live microorganisms are processed,

such as B. pertussis. Harvesting time also needs to be addressed in Tetanus toxin fermentation

and tuberculin production in order to stop the autolytic process which would, if extended, destroy

biological activity.

In the case of OPV, harvest occurs when neurovirulence is lowest (that is the most critical risk).

The virus may grow better at higher temperatures, but it may become neurovirulent. Thus, in

this case, the temperature factor is partially defined during development (i.e., how to make a

vaccine that is not neurovirulent), and partially during process validation (i.e., how to monitor

the temperature and time so that the yield is maximized but the vaccine is not neurovirulent).

The validation of harvesting can be carried out based on the yield of crude harvests which may

be tabulated, considering which falls within the IPC tests acceptance criteria. Then, taking into

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account the variability of yield of crude harvest, the acceptance limits of yield can be

determined. Low yield may be due to overheated centrifuge rotor, lost integrity of filtration

membrane, inadequate quality of filter aid, etc., depending on the harvesting method applied.

5.1.8.4.Purification

Purification is an operation usually performed by gel filtration (e.g., molecular size exclusion

chromatography, ion exchange chromatography, affinity chromatography, hydrophobic

interaction chromatography and reversed phase chromatography). Data from the supplier/vendor

normally contains details of performance, stability, extractable (and analytical methods) from

purification medium and/or equipment, which gives a very useful starting point for process

validation. The different gel filtration media produced by the suppliers normally follow validated

methods and are tested under strict control to fulfill high performance specifications.

The critical points-to-consider in the validation of a purification method or combination of

methods used are to provide a tabulation of yields and purity at each step. The verification of the

removal or dilution of product related and non-product related impurities, e.g., contaminating

cell proteins or nucleic acids, endotoxin, processing reagents, and other residual contaminants,

should be included at each step of the purification and concentration process. To facilitate

comparison through down-stream processing, a standard denominator (e.g., international units)

should be used for expressing the quantity of antigen. Process validation focuses on the elution

profile, and the yield and purity of antigen. These parameters should be within the limits set as

acceptance criteria. Impurity clearance and yields are usually evaluated through small scale

studies (e.g. spiking experiments), and testing of in process pools from consistency lots.

Validation data can therefore be reported in a Product Development Report (PDR) and process

consistency reports instead of a separated validation report.

The process of extraction is widely used in purified bacterial and viral vaccines. For example, in

bacterial vaccines of purified polysaccharides, the antigens are extracted from the cell culture

supernatants; therefore, process validation should prove that the extraction process results in the

expected quantity of antigens of appropriate immunogenicity. The acceptable range of yield shall

be determined during development studies, and used as one of the criteria of process validation.

Removal of impurities which have the potential to adversely affect product safety or intended

biological activity, or reduce it significantly, should be consistently demonstrated. It should be

based on an initial assessment considering biological activity, toxicity, quantity and proximity of

the impurity to the final drug substance. The capacity of each step to remove the relevant

impurity of the process should also be considered.

5.1.8.5.Concentration

The purpose of the concentration process is to decrease the volume of harvested antigen/culture

in order to facilitate and make the downstream processing technically feasible. The concentration

of antigens can be carried out by centrifugation, filtration or precipitation. The operational

parameters of the concentration process shall be identified and standardized during development

studies, and the acceptable range of yield shall be determined and used as one of the criteria of

process validation. As an example, diafiltration is a technique that uses an ultra-filtration

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membrane to completely remove permeate components such as salts, solvents proteins and other

biomolecules. Diafiltration is a fast and effective technique for desalting and buffer exchange of

solutions. In case of dead-end and/or cross-flow/tangential flow, the quality and quantity of

extractables and the filter sanitization process shall be also validated.

5.1.8.6.Inactivation and Detoxification

In traditional batch processes the inactivation and detoxification processes is carried out at the

start of the down-stream process, but in certain cases is done even before the harvest step in

order to assure operator safety. The most frequently used techniques for inactivation and

detoxification are heat treatment and the use of chemical agents such as formaldehyde,

glutaraldehyde, beta-propiolactone, etc., or their combination. The inactivation process

(concentration of chemicals, pH, and temperature of culture, duration of inactivation) shall be

validated in order to determine adequate operational parameters.

Certain areas, such as the cells in the head space of the fermentor, may not be completely

subjected to the inactivation process by heat/formaldehyde; therefore, a specific technique should

be applied and validated to properly address this concern.

5.1.8.7.Clarification (pre-filtration)

Clarification (pre-filtration) process step may be required for semi-synthetic culture media before

their sterilization (e.g., using activated carbon). However, most importantly, clarification is

needed for bacterial suspensions after the lysis of cell substrate to eliminate cell debris (e.g.,

toxin production after the lysis of C. tetani). In these cases, filter aids (such as diatomaceous

earth) may be applied. The clarification process should not interfere with the consequent process

steps.

5.1.8.8.Viral clearance

The cells used in cell cultures may be contaminated with animal or human viruses. ICH Q5A

“Viral Safety Evaluation of Biotechnology Products derived from cell lines of Human or Animal

Origin” (24) gives appropriate guidance on the matter. Steps that typically have the capability to

remove viruses include low pH, solvent/detergent treatment, heat and ion exchange

chromatography. Scale-down models are used including spiking the process stream of a unit

operation, and testing the processed intermediate for the virus.

5.1.8.9.Chromatography resins and reusable membranes

Validation of chromatography resins and reusable membrane lifetime should be conducted in

order to demonstrate that they can be used reliably throughout the expected lifetime. Operating

parameters, performance attributes and storage times and conditions identified in development

studies should be validated to derive acceptable operating limits.

The cleaning and sanitization procedures for resins and membranes, including the solutions

used, should be validated in order to determine the ability to eliminate carryover impurities

throughout the period of use and the number of cycles allowed. “Small scale characterization

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studies are typically performed to establish a recommended lifetime”.(1)

During routine

production, the reuse and required in-process controls should be confirmed and documented.

5.1.8.10. Buffer preparation

Factors that affect buffer preparation should be known and the corresponding manufacturing

conditions should be validated. Typical factors are mixing times, mixing conditions (RPM´s),

and temperature. In order to establish the appropriate mixing time, a series of samples are

normally taken at different time intervals. Hold times should also be determined and validated,

addressing bioburden, endotoxins, pH, conductivity, etc., as applicable.

Buffer solutions may be sterilized by membrane/cartridge 0.22 micron filtration or autoclaved.

5.1.8.11. Process Intermediates

Intermediate’s processes should be validated considering the biochemical stability through the

specified hold time, including bioburden studies if applicable. As bulks are not yet formulated,

and may be in a highly hostile environment (e.g., osmotic and heat stress, no detergent, no

stabilizer, unfavorable pH, etc.), the maximum holding time for each step needs to be

determined. It is noted that “Cumulative worst-case hold times represent the summation of

maximum unit operation hold times. Under normal manufacturing conditions, this event is

unlikely to occur and does not require validation” (1). In addition, for practical reasons, it is

difficult to validate cumulative holding times at full scale.

5.1.8.12. Blending (polyvalent vaccines)

Blending of polyvalent vaccines shall be validated by simulation of the aseptic process using

appropriate culture media.

5.1.8.13. Formulation of Bulk Product

Formulation process consists of incorporating certain sterilized salts, pre-formed gels such as

aluminium hydroxide or aluminium phosphate and buffers to the bulk antigen in an aseptic

manner. In the case of multidose vaccines, appropriately selected preservatives may be added

during the formulation process which should not interfere with the attributes of the antigen.

In the case of adjuvant use, the percentage of adsorbed antigen should be measured and the limits

of acceptability should be determined. During in situ formation of adjuvant, such as when

aluminium phosphate is applied during formulation, the quality and quantity of adjuvant should

be verified after the predetermined volumes of sterilized solutions of salts are added to the

antigen. The optimal parameters of the process should be developed and validated.

The aseptic manipulations involved in the formulation of a bulk product shall be validated by

simulation of the process using appropriate culture media to ensure an adequate aseptic

processing, as described in the section Aseptic Process Validation.

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5.2. Validation Stage II

A second validation stage, also known as Process Qualification as per FDA´s definition,

demonstrates that the process works as intended and yields reproducible commercial product,

and it should be completed before release of commercial lots. Before commencing this second

stage of process validation it is crucial to have completed validation stage I including a summary

of the development process (i.e., PDR) or a Technological Transfer Dossier, as applicable.

Manufacturing, Quality Control and QA departments are expected to review these documents for

adequacy to form the basis of validation studies and production implementation. It covers the

following elements:

5.2.1. Definition of Operational Parameters at commercial scale

Validation studies at this PV stage will be based on broad range critical operational parameters

defined during PV stage I, and given as part of the technology transfer. The aim is to determine

the operational ranges at the commercial scale environment (i.e. equipment, personnel, facility

and materials), challenging the process at different process set points if needed. “The design

space is usually established at small scale during process research and development (e.g., by

design of experiments (DOE) studies as part of characterization studies), at least for parameters

which are not scale dependent. Therefore, challenging the process at commercial scale as part of

the validation effort is not mandatory for these parameters if the scaled-down model can be

demonstrated as representative of the full-scale unit operation”(1). This approach is supported by

the FDA Process Validation (2) guidance, which states that “it is not typically necessary to

explore the entire operating range at commercial scale if assurance can be provided by process

design data”, and by PDA (1), “Justification of the operating range for each operation may not

be demonstrated during full-scale process validation; therefore, the ranges should be justified

during the development phase using appropriate process characterization studies, which for

practical reasons are usually done at lab-scale.”

Pilot batches also give an opportunity to carry out PV activities (“As part of the process

validation lifecycle some process validation studies may be conducted on pilot scale batches if

the process has not yet been scaled up to production scale” (25).

In conclusion, validation studies contribute to the understanding of process variability at

commercial scale, including raw materials, machine operating conditions, employee behaviors,

possible interruptions and deviations to standard procedures and how these can negatively affect

product quality.

An example of a PV study on lyophilization of a live virus vaccine is given below:

Validation studies consist on demonstrating that vials reach the pharmacopoeial limit of <5%

moisture in worst case scenario considering all the identified risks. The product development

team transferred the lyophilization cycle which referred to a concentration of the product (e.g.,

10x product or 4x), and the final achievement target identified for moisture content, e.g. (2%, or

4%) based on pilot stability studies, assigned shelf life, and parameters for the lyophilization

cycle. The validation team performs the necessary cycle development runs, and validates the

established cycle at commercial scale in production conditions. The validation studies will

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involve only the parameters related to commercial scale equipment and the risks identified due to

expected variations.

The example above describes a worst case scenario in which the manufacturer considers the

residual moisture content as the release criteria. Due to a wrongly designed freeze-drying

process, the product could fail to retain its biological activities even with the desired low residual

moisture content of the finished product. The freezing phase is the most critical in the whole

freeze-drying process because the product can be spoiled if the process parameters of this phase

are incorrectly established. Rapid freezing is normally preferred in order to lower the material’s

temperature to below its eutectic point, thus avoiding large ice crystal formation which may lead

to product degradation. Therefore, in freeze-drying processes, the eutectic point(s) of the product,

the age of the culture (active raw material), and the composition (excipients and stabilizers) of

the product should be considered to define critical operational parameters. Critical parameters

and their ranges are defined by the product development team (PDT), and the validation team

does not have the mandate to change them or their ranges, such as composition of the product,

but may propose different operational ranges within the allowed design space. PDT should be

able to identify the parameters which are restricted and cannot be changed or must be captured

within operating limits. Other production parameters which could be stretched to the maximum

prescribed limits by production team for the purpose of commercial production should be

included in validation studies.

5.2.2. Manufacturing of Consistency Lots

Once all the needed validation studies have determined adequate operational ranges of individual

production stages, the entire manufacturing process is finally established and now production

consistency needs to be proven. The aim of this validation level is to show that product

specifications are met in a reliable way through a series of manufacturing consistency lots at

commercial scale to demonstrate consistent and reproducible production (i.e., FDA´s Conformance

Batches as part of the Process Performance Qualification or PPQ stage). It covers the following

sequential elements and should be completed before release of commercial lots:

Qualification of facility, equipment, utilities, and related processes

Consistency Lots (Process Performance Qualification)

5.2.2.1. Qualification of Facility, Equipment, Utilities and related processes

Qualification of the manufacturing facility, equipment and utilities must have been completed

before starting the process validation study at commercial scale, including the verification that

critical equipment operate in accordance with the process requirements in all anticipated

operating ranges. Equipment operating ranges defined in the user requirements specifications

(URS) should be shown capable of being held as long as necessary during routine production.

Any modifications made to equipment, utility systems, materials, manufacturing processes or

procedures during validation studies may change the parameters or affect the expected outcomes.

Therefore, changes made during validation studies must be strictly controlled by seeking

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approval of the change before implementing it, including the evaluation of possible effects and

associated risks, in order to decide the need to execute total or partial requalification studies.

The degree of compliance needed for these studies will increase from the initial production of

clinical material (Phase 1 & 2) to the full scale process validation before commercial scale

production (or Clinical Trial Phase 3 batches).

The Qualification of Facility, Equipment, Utilities and related processes normally includes:

a. Validation Master Plan

A general Validation Master Plan pertaining to the facility describing which equipment, systems,

methods and processes will be qualified and validated and when, including a brief description of

the facility and utilities as applicable. The Validation Master Plan should indicate why and when

revalidations will be performed, either after changes or relocation of equipment or systems,

changes to processes or equipment used for processing, changes in assay methods or in testing

equipment. It also references the main quality system procedures linked to maintaining the

validated state (e.g.: deviations, CAPA, Change Control, Maintenance and Calibration). The plan

also describes the different qualification studies (Design Qualification, Installation Qualification,

Operational Qualification, Performance Qualification and Process Validation) to be performed,

as applicable.

b. Process Validation Master Plan

In addition to the general Validation Master Plan, a more detailed plan would address the

specific process validation strategies related to the specific product, approaches and sequence of

activities to be carried out according to the phase of the process (i.e., from clinical trial material

for Phase 1 and 2 studies to commercial scale or clinical trial phase 3 material, as applicable).

This plan should address how validation activities are linked to development, technology

transfer, the validation approach regarding the different unit process operations and scale down

lots and pilot batches manufacturing, if applicable. It should also mention the strategy of

manufacturing consistency lots at commercial scale, and indicate how to deal with any deviations

from the acceptance criteria of the validation protocols.

c. Sterilizing Filtration

Sterile filtration may be used at different stages of the overall production. It includes two aspects

to be validated. The first one, related to the sterilization capacity of the filter, is carried out as a

onetime study and should prove adequate filter performance in presence of the product of

interest; it covers integrity testing, and a bacterial challenge test to demonstrate that the required

sterility assurance level (SAL) is obtained. The second aspect is related to the presence of

extractables and leachables from filter media which need to be within acceptable limits in terms

of quantity and quality, without affecting the quality of the product.

Additional aspects to consider are:

Adsorption, which varies by filter type and media present (occupation of non-specific or

specific binding sites on the filtration matrix).

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Different behaviors depending on concentration and content – a detergent-dependent

protein will filter very differently if there are still micelles present.

This activity may be performed during PV stage I, provided the final product formulation is

considered.

d. Dry and Moist Heat Sterilization Process

Validation of the sterilization processes would include sterilization of equipment, autoclaving of

stoppers, and sterilization in place “SIP” of a vessel, culture media or buffer.

Depyrogenation process would typically include depyrogenation of glass containers.

The following aspects should be considered:

- Temperature distribution to detect potential cold spots (e.g., sampling ports, inlet and

outlet filters), by performing temperature profile studies with a sufficient number of

probes to be representative of the empty vessel or chamber (e.g. 10 probes). Temperature

uniformity must be proven.

- Temperature penetration and biological challenge studies are normally performed

simultaneously. For moist heat, biological indicators with moist heat resistant spores are

used. For dry heat, endotoxins are employed. The locations and number of the biological

indicators placed should be clearly described and justified in the corresponding validation

protocol and need to be representative of the types of items to be treated.

- Validation of moist heat sterilization processes of heat resistant items, buffer solutions or

empty vessels should demonstrate a six log inactivation of a heat-resistant biological

indicator system (e.g.: using 106 microorganism spores challenge, with a D value >1.5

minute). A temperature of 121.1ºC for at least 15 minutes is usually required in all parts

of the load.

- Validation of depyrogenation processes should demonstrate that a temperature profile of

250° C is attained, and an endotoxin 3-log reduction in the load is accomplished.

e. Aseptic Process Validation

Aseptic process validation consists of challenging the filtration system, the environment,

equipment and personnel in terms of aseptic processing assurance. Aseptic process validation

must be performed only after all applicable qualification studies have been completed and

approved. Aseptic manipulations differ according to the stage of the process and the type of

product. Products that have a final filtration step have lower risk of contamination of the finished

product. The filtration step/s to produce the final bulk, blending and formulation processes, and

final aseptic fill must be validated simulating the process as closely as possible using culture

media broth. Products that cannot be filter sterilized in any stage of the process (e.g.: vaccines

like DPT, MMR), have the highest risk of contamination and the validation strategy needs to

consider the aseptic processing during all manufacturing stages.

To design meaningful validation studies a thorough analysis and breakdown of the

manufacturing process must be done based, and the contamination risk assessed (e.g., using flow

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chart diagrams and tables). When designing the aseptic process, the following may be considered

in order to lower the contamination risk:

Use of single use closed system technology for aseptic connections, including aseptic

transfers from lower class rooms. These systems have no exposure to the environment.

Isolator technology

Automated sterilization in place process (SIP) is recommended whenever possible for

main production equipment, product valves and product transfer lines).

Sterile conditions of process intermediates should be demonstrated by performing media hold

tests using culture media broth in replacement of the product, simulating routine operations (e.g.,

simulating repeated thawing and freezing during OPV bulk product manufacturing), and holding

the vessel at room temperature or at 30 – 35 ºC for a period of time to allow growth (e.g. 7 to 14

days).

In order to validate the final aseptic fill, media fills are required. For new operations, equipment,

container-closure system or facilities, three consecutive aseptic process simulations must pass the

test. On a routine basis, semi-annual qualification should be conducted for each processing line

in order to evaluate the state of control of the aseptic process. Media fills should be

representative of routine production and include possible worst case situations (e.g.: engineering

interventions). Different product presentations can be grouped together using a family approach

(for more guidance on this topic, see WHO TRS 961, Annex 6, Good Manufacturing Practices

for Sterile Pharmaceutical Products).(11)

The minimum number of containers used for media fills should comply with WHO requirements

(WHO TRS 961), and be sufficient to enable a valid evaluation (10).

Points to consider for an adequate Media Fill validation study design:

Clearly state the aseptic processes covered by the study.

Routine and nonroutine interventions should be simulated (e.g., glass breakage, shift change,

transfers, procedures to keep product warm or cold, etc.). Events which are not within the

expected controlled operations should not be simulated.

Minimum frequency of twice a year as a minimum for processes operating under routine

conditions, and should include all authorized staff.

Any change in equipment, container-closure system or facilities, might trigger a media fill

study, based on the corresponding change control process.

“When data from a media fill indicate the process may not be in control, an investigation should

be conducted to determine the origin of the contamination and the scope of the problem. Once

corrections are instituted, process simulation run(s) should be performed to confirm that

deficiencies have been corrected and the process has returned to a state of control. When an

investigation fails to reach well-supported, substantive conclusions as to the cause of the media

fill failure, three consecutive successful runs in tandem with increased scrutiny of the production

process may be warranted”(27).

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f. Cleaning Validation

The cleaning methods employed shall consistently control potential carryover of product,

cleaning agents and extraneous material into subsequent product to a level which is below

predetermined limits.

Manufacturers may have different cleaning requirements based on the stage of the process, and

the subsequent product to be manufactured. The higher the risk of having finished product cross

contamination, the greater the requirement to validate cleaning methods to ensure product safety.

In order to design and justify an adequate cleaning validation strategy it is essential to understand

the nature and risks of the potential product residues to the patient, the manufacturing step, and

the equipment and the utilities involved. It depends largely on considering the following

scenarios:

The equipment usage (i.e. dedicated equipment or multipurpose)

The stage of manufacture (early, intermediate or final step)

Series of batches in-campaign or a product changeover

Possible residue level from potential build-up of same product impurities.

Cleaning agent residue, if used

Presence of components with a potential for accumulation / adsorption / precipitation etc.,

given the possible concentrations, materials and conditions

The nature of the potential contaminants (toxicity, solubility etc.)

Potential for live and inactivated microorganisms to be mixed

Elements added later to the process would kill / modify / oxidize new materials coming

in, or downstream steps that would purify any possible level of contaminants

Disposable vs. reusable product-contact equipment/accessories.

Automated CIP vs. manual cleaning

Use of 100% fresh water, or recirculated water for washing/rinsing purposes of product

contact surfaces.

Cleaning validation of a fermenter is of particular importance when the equipment is a

multiproduct one, and should demonstrate that the product and cleaning solutions (if applicable)

residues are reduced to acceptable limits. Air supply inlet/outlet or the exhaust system should be

checked (e.g., by swab sampling). The microbiological aspect should also be included as part of

the validation study in order to define a cleaning expiration date.

In addition to cleaning validation, routine verification of selected residues or their indirect

measurement may be required, especially for manual cleaning processes (e.g.: using TOC or

conductivity).

In a multipurpose setting, a prioritized matrix/bracketing approach of selected compound

residues to be verified after cleaning could be based on toxicity and safety data to reduce the

validation scope while still ensuring a proper cleaning validation study.

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5.2.2.2. Consistency Lots

As part of validation stage 2, the manufacture of consistency lots marks the transition between

development and clinical material manufacturing and commercial scale production. Once all

required studies and validation of individual production steps have been successfully

accomplished, the entire manufacturing conditions and operational parameters are finally

established and defined in a Master Batch Record. Now the entire process must be shown to

meet specifications in a reliable way through a series of manufacturing lots at commercial scale

to demonstrate consistent and reproducible production. The master batch record should specify

the processing parameters and acceptable ranges for all processing steps at the required level of

detail to allow reproducibility of the process (e.g., time periods, pH, volumes, temperatures,

measurements, specifications, acceptable ranges).

An enhanced sampling strategy used during the manufacture of consistency lots gives an

adequate opportunity to prove the robustness of the process, and should be well justified.

“Process Validation will have a higher level of sampling, additional testing, and greater scrutiny

of process performance than would be typical of routine production. The level of monitoring and

testing should be sufficient to confirm uniform product quality throughout the batch. The

increased level of scrutiny, testing, and sampling should continue through the process

verification stage as appropriate, to establish levels and frequency of routine sampling and

monitoring for the particular product and process”.(2)

Process Validation should be performed by manufacturing a sufficient number of successful

consecutive lots to demonstrate process robustness at the target operating set points to assess

process variability expected during routine production. “Process characterization (robustness)

studies conducted during stage I serve as the foundation for establishing normal operating

ranges, proven acceptable ranges and design space, as appropriate” (22).

The manufacturing process must successfully meet all acceptance criteria and product

specifications each time to be considered a consistent process. For newly developed products, the

approach of producing three validation production scale batches should be considered as a

minimum requirement, and may require additional lots. It could also be less when changes are

introduced in existing validated manufacturing processes, if proper documented justification

based on risk assessment is generated. As a basic useful concept, the number of process runs

carried out and observations made should be sufficient to allow the normal extent of variation

and trends to be established and to provide sufficient data for evaluation, and will also depend on

“the level of process knowledge and understanding gained from Stage I, and the type and

complexity of manufacturing technology employed…”(22).

Conclusions about a commercial manufacturing process can only be made after the process

validation protocol is executed and data evaluated. Process Validation batches which have not

met the established acceptance criteria cannot be considered for commercial use. The relevant

acceptance criteria in this case, relates to product specifications and not to consistency /

comparability criteria.

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5.2.3. Manufacturing of Clinical Phase Material

During the manufacturing of clinical phase III material, process validation may be completed for

its ability to consistently meet product specifications demonstrated in a documented way at a

commercial scale. Usually Phase III Clinical Trial batches are similar to commercial batches

unless otherwise accepted by the regulator.

There is usually confusion on when does the process validation start. The foundation of a

validated process is not established in one phase. Step by step layers of knowledge and data

collected from R&D stage, and through phase I, II and III material manufacturing before

initiation of commercial scale batches lay down the foundation of sound process validation

studies. The simplest explanation is that all the data collected before the final validation or

consistency runs may form the basis or foundation of compliant validation studies.

Manufacturers may erroneously claim to conclude their validation studies based on data

generated from pilot scale batches or Phase II clinical trial batches. This approach may be

misleading as the scale of manufacturing for Phase III or commercial batches could be very

different. This significant scale difference may introduce unknown risk and parameter changes in

production processes. Thus, it is important to conclude the validation studies after thoroughly

evaluating the data from Phase III or consistency lots at commercial scale.

Each single production lot at each scale should be fully analysed applying all available methods.

The understanding or the outcome of this analysis should form the basis of in-process control

and final quality control. Only when acceptable ranges are set for commercial processes, the

validation process may be considered to be concluded.

A common sequence of Process Validation activities (1) is shown in Figure 1, including their

relationship to other development activities and clinical phases. Further information regarding

pharmaceutical development is described in ICH Q8 (6)

and ICH Q11 (15)

.

Note: For Phase I clinical material manufacturing there is no specific process validation

requirement, however, the basic GMP rules must be followed, as mentioned in FDA´s CGMP for

Phase 1 Investigational Drugs (26).

5.2.4. Bracketing, Family and Matrix Validation Approach

Any product specific process should be validated separately. However, in some well justified

cases (same product with different strains used in the same facility, same diluent for different

lyophilized products, identical equipment arrangement and manufacturing procedure, etc.), a

bracketing, matrix or family approach could be used, if properly documented. As an example, a

matrix strategy may be applied for different serotypes of a vaccine, validation of culture media,

and buffers when processing and components are very similar. This concerns for instance the

validation of multi-product transfers to a new formulation or filling building. The approach could

consist in grouping products into formulation or filling families and applying a matrix approach

whereby representatives of the families are validated and results extrapolated to the family

grouping. The principle would be to produce at least three consistency lots of the representative

product of a concerned family but only one lot of each other member of this given family. It will

be to the applicant to justify the families and their representatives. The underlying basis for

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accepting this type of approach is that: i) the validation approach concerns only to registered

products for which consistency and stability profile already exists, ii) no modification to the

current manufacturing processes or to the current vaccine composition is sought, and iii) the new

facilities and equipment are appropriately and fully validated through classical PQ validation.

5.2.5. Documentation Requirements

An effective document control system is expected to be in place in order to manage all process

validation protocols, data and associated information. This system should describe how to

prepare, identify, approve, execute, file, amend and change documents, with focus in validation

protocols and reports. The validation document requirements should be identified including the

Validation Master Plan and a SOP describing how to prepare process validation protocols and

reports, and related documents (e.g.,: characterization studies).

It is essential that development studies also be documented, including the basis for decisions

made about the process.

5.2.6. Personnel Training and Qualification

Validation staff and contractors involved with the preparation and execution of validation studies

should have the appropriate education, training, and experience to perform the assigned tasks,

and this training documented. Manufacturing personnel should also be fully trained in the

production operations before starting with the process validation study. The efficacy of the

training effort should be verified in a documented manner. Poor training is often seen as the

cause of failed validation activities.

5.2.7. Process Technology Transfer

According to ICH Q10, “the goal of technology transfer activities is to transfer product and

process knowledge between development and manufacturing, and within or between

manufacturing sites to achieve product realization. This knowledge forms the basis for the

manufacturing process, control strategy, process validation approach and ongoing continual

improvement”(8). According to WHO, “it is a logical procedure that controls the transfer of any

process together with its documentation and professional expertise between development and

manufacture or between manufacture sites” (12)

.

A given technology could be transferred within the same group of companies or between

companies of different ownership. As the process to be transferred is given and validated, the

main focus of PV is aimed at qualification and validation of facilities, materials, equipment and

processes sourced by the recipient. A documented gap analysis is normally done to identify

differences in equipment, materials, and manufacturing process in order to plan the PV activities.

As the technology transfer is basically transfer of knowledge and experience, crucial factors for

success is project planning, the adequacy of human resources at the recipient side, and to

establish well defined communication channels. Ideally, key technical personnel should first be

thoroughly trained in the relevant SOPs at the provider’s facility before training would start at

the recipient’s plant. For specific guidance on technological transfer refer to World Health

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Organization WHO Technical Report Series, No. 961, 2011 Annex 7 WHO guidelines on

transfer of technology in pharmaceutical manufacturing.(12)

5.2.8. Legacy products

This guidance primarily applies to new products although legacy products may also benefit from

adopting such an approach. For legacy products it is acknowledged that the current standards

cannot always be fully addressed in a retrospective manner, therefore, in this scenario, the

available validation documentation shall be assessed and the gaps addressed by performing the

necessary studies. For instance, the history of the production cell /virus substrates may not be

fully documented, and the historical changes of the manufacturing process, both upstream and

downstream, may not be documented adequately. Examples of those changes may be modifying

culture propagation (e.g., surface or submerged culture; shake flasks, cell factories or

homogeneous culture; type of fermentation equipment and scale; type of impeller, type of

aeration, origin of the master cell bank, etc.), change of harvest and inactivation of culture, etc.

In order to use a retrospective validation approach for legacy products, changes must have been

documented and controlled during the period of time considered (e.g., process changes, raw

materials changes). The period of time considered and the number of lots needed must be well

justified and documented. “Data from batch documents, process control charts, maintenance log

books, and finished product test results, including trend analyses and stability results, are used

for validation”.(17)

Typically required information is listed below:

Product Quality Attributes in the different process stages;

Specifications and control methods of the finished product, intermediates and raw materials;

In Process Controls specifications and control methods;

Flow chart of manufacturing operations in each step and associated equipment;

List of all manufacturing operations of each production stage, with defined ranges;

List of all equipment with their qualification status;

Analytical data (if available) from each of the intermediates and final product;

List of process related deviations and OOS;

Justification for finished product and intermediates specifications; and

Process Variables studied and their classification, including ranges.

5.2.9. Design and Execution of Process Validation Studies

Basic elements of a meaningful validation study to be applied to any validation stage may be

summarized as follows:

Clear objective / Ask the right question.

Address all the risks and variations (e.g. identified in the PDR)

Define the right acceptance criteria.

Use methods with the specificity and sensitivity to address the question.

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Use appropriate statistical methods to formulate conclusions.

Review the result based on the acceptance criteria, draw conclusions and decide what

activities are required.

Note: Deviations to acceptance criteria found during validation studies require to be studied

to determine the impact on the process validation, and in the process itself.

Execution of validation studies should be based on pre-approved protocols, reviewed and

approved by all appropriate departments and the quality unit. A working copy of the protocol and

test record sheets should be issued by QA to perform the study. Validation protocols should

describe the approach and the plan to execute the study, including the manufacturing conditions,

controls, sampling plan, testing, and acceptance criteria. The validation protocol should contain

as a minimum the following elements:

Objectives and scope

Validation team qualifications and responsibilities

Type of validation: prospective, concurrent, retrospective, re-validation

Rationale, number and selection of batches to be on the validation study

Equipment list to be used; their normal and intended operating parameters

Outcome of IQ, OQ, PQ for critical equipment, as a prerequisite

Description of processing steps: copy of the master documents for the product

Sampling points, stages of sampling, methods of sampling, sampling plans

Training requirements for the processing operators

Validated test methods to be used in in-process testing and for the finished product

Specifications for raw materials and packaging materials

Forms and charts to be used for documenting results

Presentation of results, documenting conclusions for study approval.

Calibration requirements.

Test Procedure Sequence of tests to be performed (in-process, release, characterization)

and acceptance criteria for each significant processing step

Sampling plan, including number and frequency of samples. There should be a rationale

for the sampling strategy, providing sufficient statistical confidence of quality both within

a batch and between batches

A description of the statistical methods to be used in analyzing all collected data (e.g.,

statistical metrics defining both intra-batch and inter-batch variability)

Critical operational parameters that are being validated must be clearly stated (e.g.:

pressure, pH, viability).

Each validation test must include: Test Objective, Materials/Equipment/Instruments,

Methodology, Documentation required for the test or documentation / evidence to be

generated / Data Handling & Processing, Acceptance Criteria, Conclusion / Outcome of

Test.

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5.2.10. Deviations Management

Any validation test result not meeting the predefined acceptance criteria must be documented,

described, assessed in regards to the impact, and there should be a decision made to repeat the

individual test, accept it as a limitation of the validation exercise, or to consider the validation

study as a failure. An investigation should be carried out if applicable, especially for process

related deviations.

5.2.11. Final Report

After all validation activities have been finalized, a final report should be prepared documenting

the outcome of the study protocol.

This report should include:

Objective and basic approach used for the study;

Summary of the overall outcome of the study;

Summary of data collected; interpretation of the results should be clearly and concisely be

compared to the predefined acceptance criteria, in order to support the outcome of the study;

Summary of manufacturing out of normal events, deviations and corrective actions

proposed;

A clear conclusion as to whether the data indicates the process met the conditions established

in the protocol and whether the process is considered to be validated and approved for

routine production. If not, the report should state the causes of the failure, and what should be

accomplished before such a conclusion can be reached. Include all appropriate department

and quality unit reviews and approvals, as necessary.

5.3. Validation Stage III

A third validation stage (FDA´s Continued Process Verification) is based on a program designed

to ensure that validated processes remain in a state of control. There are three main aspects to

consider in this phase:

Strong change control system,

Sound revalidation program as applicable, and

Continued monitoring of process variables through time to allow the opportunity to make

adjustments to compensate for process variability and to ensure the manufacturing process

remains consistent.

“Since all sources of potential variability may not be anticipated and defined during validation

stages 1 and 2, unanticipated events or trends identified from continued process monitoring may

indicate process control issues and/or highlight opportunities for process improvement”(22).

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During this validation stage, continued process verification provides additional assurance that the

routine production process is and remains in a validated and controlled state, even as materials,

equipment, production environment, personnel, and manufacturing procedures change.

Throughout this validation stage, the process and product knowledge and understanding captured

during stages I and II continues to build up. As part of this process, CAPA provides an effective

system for feedback, feed forward and to achieve continual improvement.

Manufacturers should regularly collect and analyze product and process data to evaluate the

validated state of the process, to detect undesired process variability, identify the need to

revalidate, identify process or product problems, and to look for opportunities for process

improvements. The data collected should include relevant process trends and quality indicators

of incoming materials, components, in-process material, and finished products. The data should

be statistically trended and reviewed by trained personnel. The information collected should

verify that the quality attributes are being appropriately controlled throughout the process, to

evaluate process control and capability, and product stability. Several tools and techniques, some

statistical and others qualitative, can be used to detect variation, characterize it, and determine

the possible root causes. Scrutiny of intra-batch as well as inter-batch variation is part of a

comprehensive continued process verification program. A thorough Annual Product Review is

one of the recommended tools to achieve this objective.

Continued monitoring of operational parameters and quality attributes at the level established

during PV Stage II is recommended for PV Stage III until sufficient data is available to generate

significant variability estimates. These estimates can provide the basis for establishing levels and

frequency of routine sampling and monitoring for the particular product and process. Monitoring

can then be adjusted to a statistically appropriate and representative level. Process variability

should be periodically assessed and monitoring adjusted accordingly.

Variation can also be detected by timely assessment of complaints, out-of-specification, process

deviation reports, process yield variations, batch records, incoming raw material records, and

adverse event reports (e.g.: during annual product review). Production line operators and quality

unit staff should be encouraged to provide feedback on process performance such as variations,

OOS, deviations and failures.

Validated processes must be kept in a state of control throughout the life of the process as

materials, equipment, production environment, and personnel may change. Maintenance of the

facility, utilities, and equipment is another important aspect of ensuring that a process remains in

control.

5.4.Revalidation

Once the system or process has been validated, it is expected that it remains in control, provided

no changes are made. In the event that modifications are made, or equipment is replaced or

relocated, partial or full revalidation studies could be needed (3). These situations must be strictly

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handled through the appropriate Deviation Handling, CAPA, Change Control and Risk

Assessment.

A fully implemented and effective change control program is required as per GMPs, and it is

especially critical in order to keep the validated state. This program will evaluate the impact of

any proposed change on the validated system, and will identify any need to perform additional

partial or full re-validation studies. This evaluation should be handled by a team with experts

from relevant areas (e.g.: Manufacturing, Quality, R&D, Engineering) in order to assess the need

for revalidating the process. Any critical change should be described, well-justified, and include

an implementation plan, which needs to be previously approved by the Quality unit. Depending

on how the proposed change might affect product quality, additional process design and process

qualification activities could be warranted. Where no significant changes have been made to the

system or process, and a quality review confirms that the system or process is consistently

producing material meeting its specifications, there is normally no need for revalidation”. (13)

This revalidation approach may be described as event/change-driven.

WHO recommends that “systems and processes should be periodically evaluated to verify that

they are still operating in a valid manner’, as it is the case for high risk processes such as aseptic

process validation, a time-driven approach is expected (e.g., aseptic process validation performed

twice a year, sterilization and depyrogenation processes performed yearly).

5.5.Validation Studies and the WHO Pre-Qualification process Expectations

Expectations from the WHO Pre-Qualification programme (PQ) are that during the

manufacturing of Phase 3 clinical material, consistency lots (i.e. PV lots) will be produced as

part of adequate validation studies. It is expected that validation studies be reviewed in detail by

NRA and NCL of country of origin before granting the marketing authorization of the product.

The summary review of validation studies during WHO PQ process is done in two stages, i.e.

during PSF review, and then during the manufacturing site audit. The re-validation aspect is

reviewed annually during the screening of Prequalified Vaccine Annual Report (PQVAR) (21)

which includes details of all changes introduced during the previous year.

WHO PQ process focuses on adequacy of the following aspects:

Inclusion of Risk assessment in validation studies,

Conformance of current validation activities,

Policies for routine validation and revalidation

Change control and Deviation management

Critical validation deviations like failure to have cleaning validation of critical steps,

inactivation validation, uncontrolled risk of cross-contamination, etc.

Continued process verification through trend analysis.

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1

2

3 L

I

C

E

N

S

U

R

E

Figure 1. Common Sequence of Process Validation Activities (based on PDA´s Common Timing of

PV Enablers and Deliverables to Validation Stage Activities). (22)

Process Validation Activities Clinical Phases Supporting Activities

Initiate process & assay development

Initiate preliminary protein characterization

Establish preliminary reference standard

Initiate clinical material manufacturing

Initiate Stability studies

Submit IND application

Conduct continuing process & assay

development

Qualify or validate assays

Establish protein characterization

Establish protein definition

Conduct pivotal clinical trials

Manufacture conformance / consistency lots

Submit regulatory license application

Pass regulatory agency pre-approval

inspection

Obtain regulatory approval

Conduct commercial manufacture &

distribution

Implement ongoing process monitoring

Preliminary clearance of process impurities

Initiate Virus Clearance studies

Initiate process characterization studies (test

limits)

Approve Process Validation Plan

Approve Process Validation protocols

Conduct additional Virus Clearance studies

Execute full scale Validation

Execute small scale validation studies (e.g.

impurity clearance, hold times)

Develop process validation summaries for

filing

Complete, approve, archive process

validation reports

Evaluate Operational Parameter ranges

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C

A

P

A

C

H

A

N

G

E

C

O

N

T

R

O

L

Appendix 1

Outline of R&D, product development and commercial production in the context of

Process Validation (based on PDA´s Common Sequence of Process Validation Activities). (1)

R&D Design and Development of API or drug product formulation

Product

development

Stage 1

validation

activities

-Tech transfer to Lab scale for clinical material manufacturing

(phase 1, 2)

-Process Description / Process Characterization

-Process Control Strategy of Unit Manufacturing Operations &

entire process

Operational Parameters Ranges / Mixing times

/Blending

Material Compatibility / Extractables / Leachables

Hold Times / Sterility assurance

Finished product / Intermediates / Raw Materials /

Packaging Materials Specifications and test methods

-Scale-up and tech transfer for clinical material manufacturing

(phase 3) and commercial scale production

Stage 2 –

Process

Qualification

Commercial

scale

production

-Scale up processes, optimizing process parameters; identify

ranges of acceptability, establishing potency & stability criteria

-Design, installation, operational and Performance

Qualification of facility, utilities, process equipment

-Quality System Prerequisites

-Prepare clinical study material for phase 3

-Complete Process Validation Studies / Consistency Lots

Stage 3 –

Post-

Validation

Continued

Verification

Trend Analysis / Statistical Analysis / Stability Information

Complaints / AEFI

Quality System and Management Review

Annual Product Review

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Glossary

Performance parameters: process outputs that may be monitored to ensure acceptable process

performance. Process performance indicators might include measurements such as concentration, yield, or

cell mass/growth rate and may demonstrate consistency and robustness of a process. (1)

Critical operational parameter: reserved for a limited sub-set of parameters that significantly affect

product quality attributes when varied outside a meaningful or narrow (or difficult to control) operational

range. Critical product quality attributes might include product potency, glycoform distribution, or levels

of aggregated or clipped forms of the target protein. (1)

Non-critical operational parameters: are all other parameters considered outside the critical operational

parameters. (1)

Lifecycle Approach: The lifecycle concept links product and process development, qualification of the

commercial manufacturing process, and maintenance of the process in a state of control during routine

commercial production. (2)

Critical Quality Attribute: Attributes that describe a parameter or item that must be controlled within

predetermined criteria to ensure that the medicinal product meets its specification (ICH Q7A)

Validation: Action of proving, in accordance with the principles of GMP, that any procedure, process,

equipment, material, activity or system actually leads to the expected results. (10)

Qualification: Action of proving that any premises, systems and items of equipment work correctly and

actually lead to the expected results. The meaning of the word “validation” is sometimes extended to

incorporate the concept of qualification. (10)

Process Validation (PV) is the documented evidence that the process, operated within established

parameters, can perform effectively and reproducibly to produce a drug substance or intermediate meeting

its predetermined specifications and quality attributes (ICH Q7). Process validation involves the

collection and evaluation of data, from the process design stage throughout production, that establish

scientific evidence that a process is capable of consistently delivering a quality drug substance. (6)

Unit Operation: A discrete step or manipulation in a manufacturing process where process and operating

parameters are defined to achieve a specific process objective (1)

Continued process verification: Assuring that during routine production the process remains in a state

of control. (2)

Process design: Defining the commercial manufacturing process based on knowledge gained through

development and scale-up activities. (2)

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Process qualification: Process qualification is the process validation stage where the process

design is evaluated to determine if the process is capable of reproducible commercial

manufacturing.

State of control: A condition in which the set of controls consistently provides assurance of continued

process performance and product quality. (2)

Consistency Lots: see Process Performance Qualification (PPQ)

Process Performance Qualification (PPQ): the second element of the Process Qualification stage, It

includes a combination of the actual facility, utilities, equipment, and the trained personnel with the

commercial manufacturing process, control procedures, and components to produce commercial batches,

A successful PPQ will confirm the Process Design and demonstrate that the commercial manufacturing

process performs as expected. Batches prepared are also called Conformance Batches, Consistency Lots

or PPQ batches (2)

Concurrent validation

Validation carried out during routine production of products intended for sale.

Prospective validation

Validation carried out during the development stage on the basis of a risk analysis of the production

process, which is broken down into individual steps; these are then evaluated on the basis of past

experience to determine whether they may lead to critical situations.

Retrospective validation

Involves the evaluation of past experience of production on the condition that composition, procedures,

and equipment remain unchanged.

References

(1) PDA Technical Report No. 42, Process Validation of Protein Manufacturing. Supplement Vol. 59, No.

S-4, 2005.

(2) Guidance for Industry. Process Validation: General Principles and Practices. Current Good

Manufacturing Practices (CGMP). Revision 1. U.S. Department of Health and Human Services. Food and

Drug Administration, January 2011.

(3) A WHO guide to good manufacturing practice (GMP) requirements. Part 2: Validation. World Health

Organization, 1997.

(4) CBER US FDA: Guidance for Industry: Content and Format of Chemistry, Manufacturing and

Controls Information and Establishment Description Information for a Vaccine or related product.

January 1999.

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(5) CBER US FDA: Guidance for Industry: Characterization and Qualification of Cell Substrates and

Other Biological Starting Materials Used in the Production of Viral Vaccines for the Prevention and

Treatment of Infectious Diseases. September 2006.

(6) ICH guideline Q11 on development and manufacture of drug substances (chemical entities and

biotechnological/biological entities).EMA/CHMP/ICH/425213/2011, May 2011.

(8) ICH Harmonized Tripartite Guideline. Pharmaceutical Quality System Q10. Current Step 4 version, 4

June 2008

(10) Annex 3 WHO good manufacturing practices for pharmaceutical products: main principles. World

Health Organization WHO Technical Report Series, No. 961, 2011.

(11) Annex 6 WHO good manufacturing practices for sterile pharmaceutical products. World Health

Organization WHO Technical Report Series, No. 961, 2011.

(12) Annex 7 WHO guidelines on transfer of technology in pharmaceutical manufacturing. World Health

Organization WHO Technical Report Series, No. 961, 2011

(13) Annex 2 WHO good manufacturing practices for active pharmaceutical ingredients. World Health

Organization WHO Technical Report Series, No. 957, 2010.

(14) ICH Q2B “Validation of Analytical Procedures Methodology”. November 1996.

(15) ICH Q8 International Conference on Harmonisation of Technical Requirements for Registration of

Pharmaceuticals for Human Use: ICH Harmonised Tripartite Guideline, Pharmaceutical Development

Q8, Current Step 4 version, 9 November 2009.

(16) PDA Filter Validation Technical Report

(17) How to get your biological product to market and keep it there. Jerry Calver, Ph.D. 2011

(18) ICH Q9 II.6 (Quality Risk Management as Part of Production Validation)

(21) Procedure for assessing the acceptability, in principle, of vaccines for purchase by United Nations

agencies, WHO/BS/10.2155.

(22) Process Validation: A Lifecycle Approach. PDA TR 60, 2013.

(23) ISPE. (PQRI) Process Robustness – A PQRI White Paper, Pharmaceutical Engineering, Nov/Dec

2006, ISPE Online Exclusive http://www.pqri.org/pdfs/06ND-online_Glodek-PQRI pdf

http://www.pqri.org/pdfs/06ND-online_Glodek-PQRI

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(24) ICH Topic Q5A (R1) Quality of Biotechnological Products: “Viral Safety Evaluation of

Biotechnology Products derived from cell lines of Human or Animal Origin”. European Medicines

Agency. October 1997. CPMP/ICH/295/95

(25) Guideline on Process Validation; 29 March 2012; EMA/CHMP/CVMP/QWP/70278/2012-Rev1;

Committee for Medicinal Products for Human Use (CHMP); Committee for Medicinal Products for

Veterinary Use (CVMP)

(26) FDA´s CGMP for Phase 1 Investigational Drugs Guidance for Industry CGMP for Phase 1

Investigational Drugs; U.S. Department of Health and Human Services

Food and Drug Administration; Center for Drug Evaluation and Research (CDER) Center for Biologics

Evaluation and Research (CBER); Office of Regulatory Affairs (ORA); July 2008.

(27) Guidance for Industry Sterile Drug Products Produced by Aseptic Processing —

Current Good Manufacturing Practice. Food and Drug Administration. 2004

Additional recommended references:

World Health Organization. WHO Technical Report Series, No. 937, 2006. Annex 4

Supplementary guidelines on good manufacturing practices: validation

- Appendix 3 Cleaning validation

- Appendix 4 Analytical method validation

- Appendix 6 Qualification of systems and equipment

Active Pharmaceutical Ingredients Committee (APIC) Cleaning Validation in Active pharmaceutical

Ingredient manufacturing plants, September 1999.

ICH Harmonized Tripartite Guideline Pharmaceutical. Quality Risk Management Q9, Current Step 4

version, 9 November 2005

Finney, D.J. Statistical Methods in Biological Assay. 2nd

edition, Griffin: London, 1964.

Qualification and validation. Working Party on Control of Medicines and Inspections,

Final Version of Annex 15 to the EU Guide to Good Manufacturing Practice, 2001

Acknowledgements

This draft note for guidance was prepared by Victor Maqueda, Buenos Aires, Argentina, with the valuable

expert contribution of Dr. Zoltan Csizer, Scott Lambert, Anil Chawla and IFPMA (International

Federation of Pharmaceutical Manufacturers & Associations). Other collaborators who assisted in the

preparation of this draft were Abel Olivera and José Luis Monteagudo.

validation of production processes for vaccines for who ... · page 2 of 37 this guidance document...

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