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Microbial Monitoring - Bioburden - Pda Journal May June 2015

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ARTICLE © Biophorum Operations Group Ltd This paper will be published in a ‘Special Section’ of the PDA Journal of Pharmaceutical Science and Technology, in May/June 2015. Microbial Monitoring For Biological Drug Substance Manufacturing: An Industry Perspective. Authors Diane Hardy, Chief Microbiologist, Regeneron Brian L. Bell, Senior Scientist, Bristol-Myers Squibb Ren-Yo Forng, Site Microbiologist, Astra Zeneca Michael Knight, Senior Manager QC Microbiology, Genentech Anita Bawa, Director QC, Bayer Stephanie Ramsey, Manager Quality Systems, Baxter Christine Arbesser-Rastburg, Director Quality Operations / Microbiology, Baxter Mousumi Paul, Associate Director Engineering, Merck Christopher Ton, Associate Director, Merck Fran Leira, Global MSAT / QC Head, Lonza Claudia Roman, Site Head QC Microbiology, GlaxoSmithKline Kim McFarland, Director QC Microbiology, Alexion David Phillips, Senior Director QC, Shire Jean Stuckey, Manager QC Microbiology / Lab Services, Patheon Christian Bauer, Head of Biotech Compliance and Projects, Sanofi Andreas J. Calvo, Senior Scientist, AbbVie Corresponding author: David Bain, Facilitator, BPOG Corresponding author contact information: BPOG, 5 Westbrook Court, Sharrow Vale Road, Sheffield, S11 8YZ, United Kingdom, [email protected]
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Page 1: Microbial Monitoring - Bioburden - Pda Journal May June 2015

ARTICLE

© Biophorum Operations Group Ltd

This paper will be published in a ‘Special Section’ of the PDA Journal of

Pharmaceutical Science and Technology, in May/June 2015.

Microbial Monitoring For Biological Drug Substance Manufacturing: An Industry Perspective.

Authors

Diane Hardy, Chief Microbiologist, Regeneron

Brian L. Bell, Senior Scientist, Bristol-Myers Squibb

Ren-Yo Forng, Site Microbiologist, Astra Zeneca

Michael Knight, Senior Manager QC Microbiology, Genentech

Anita Bawa, Director QC, Bayer

Stephanie Ramsey, Manager Quality Systems, Baxter

Christine Arbesser-Rastburg, Director Quality Operations / Microbiology, Baxter

Mousumi Paul, Associate Director Engineering, Merck

Christopher Ton, Associate Director, Merck

Fran Leira, Global MSAT / QC Head, Lonza

Claudia Roman, Site Head QC Microbiology, GlaxoSmithKline

Kim McFarland, Director QC Microbiology, Alexion

David Phillips, Senior Director QC, Shire

Jean Stuckey, Manager QC Microbiology / Lab Services, Patheon

Christian Bauer, Head of Biotech Compliance and Projects, Sanofi

Andreas J. Calvo, Senior Scientist, AbbVie

Corresponding author: David Bain, Facilitator, BPOG Corresponding author contact information: BPOG, 5 Westbrook Court, Sharrow Vale Road, Sheffield, S11 8YZ, United Kingdom, [email protected]

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© Biophorum Operations Group Ltd

Introduction

The purpose of this paper is to provide guidance and drive consistency in regards to

microbial control for manufacturers of low bioburden bulk biologics. This paper provides

recommendations based on biologics produced using cell cultures such as monoclonal

antibody (mAb) based products, and recombinant protein manufacturing process. These

recommendations, from the members of the BPOG Bioburden Working Group, are intended

to assist biopharmaceutical manufacturers develop microbial monitoring strategies and

product safety assessments. Each manufacturer is unique, therefore, alternative strategies

may be justified and/or qualified.

Scope

This paper focuses on the following topics:

Microbial in-process monitoring during inoculum expansion

Culture expansion, and protein purification process of bulk drug substances

Setting alert/action levels limits

Objectionable organisms in bulk biologics, responding to bioburden excursions

Assessing impact to product quality

Background

The biopharmaceutical industry produces non-sterile bulk biologics (i.e. Drug Substances)

using bioburden controlled processes in accordance to Q7A and Annex 2. Sterile final

dosage forms are produced in accordance to Annex 1. A mammalian cell mAb process

consists of upstream and downstream processes. Upstream operations include the protein

production phase of manufacturing where the host cells are grown to generate the product

molecule. Primary recovery (centrifugation and depth filtration) is the first step in removing

the unwanted production components while retaining the product molecule. Capture of the

target molecule is often achieved with affinity chromatography. Some firms chose to perform

capture as a part of downstream manufacturing. Downstream operations, which typically

include chromatography, viral clearance, concentration and diafiltration, progressively refine

the product to its final bulk form suitable for manufacturing into the final drug product.

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The following diagram illustrates a generic mammalian cell mAb process.

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In-Process Product Stream Monitoring and Testing

A comprehensive in-process sampling and testing plan is necessary to monitor and

control the biological manufacturing processes. The following sampling approach is

typically incorporated as part of the general sampling plan. Additional sampling

locations may be necessary in some cases due to specific process considerations.

In general, samples for bioburden and/or endotoxin should be taken at critical

process steps, e.g. pre-filtration samples, or after hold times, where bioburden could

get introduced into the process or proliferation could occur. Such sampling points

for bioburden and/or endotoxin should be determined and documented by

performing a risk analysis of the manufacturing process (prior to establishing the

sampling and testing program).

Sample Collection

Bioburden/endotoxin sample containers and procedures are key elements of

the overall monitoring program given the potential risk of false positive and

negative results. Materials must be well mixed just prior to sampling.

Containers used for bioburden sampling must be sterile. The recommended

containers include disposable systems that are closed to the environment and/or

sampling assemblies with equipment interfaces that can be cleaned or steamed with

the manufacturing equipment.

Containers used for endotoxin sampling must be sterile, pyrogen-free and made of a

material that does not interfere with the recovery of endotoxin (e.g. glass,

polystyrene).

Containers used for both bioburden and endotoxin sampling should be dedicated to

minimize the number of times the sample is manipulated prior to testing. Where

relevant, sampling flow paths may need to be flushed to ensure the process and

fluids from previous sampling operations are expelled so process/sample integrity

are not compromised. Technicians that perform sampling operations must be

trained in proper sampling techniques. The manipulation of bioburden samples on

the manufacturing floor should be minimized as much as possible prior to delivery to

Quality Control (QC), which should occur as soon as possible. Bioburden samples

are recommended to be stored at 2-8ºC and tested within 24 hours of collection.

Process Media Preparation

To evaluate bioburden levels associated with media preparation, it is

recommended that an appropriate number of batches at scale, based on

statistical analysis and/or risk assessment, are sampled/tested for

bioburden/endotoxin just prior to filtration or sterilization of the media.

Preferably, batches should be sampled/tested prior to Process Validation

batches, for bioreactor media (for all bioreactors in the process). This data

may be used to support the maximum hold time of media prior to sterilization.

Media preparation for bioreactor steps is typically the longest preparation for

upstream solutions. Where processes include complex feeds with several

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preparation steps (e.g. protein hydrolysates), the feeds should also be

considered for sampling and testing.

Routine monitoring of bioburden/endotoxin at this step may not be needed

when maximum media preparation and filtration times are established.

However, periodic monitoring is recommended annually or after prolonged

shutdowns.

Buffer Preparation

For filtered buffers, it is recommended that bioburden and endotoxin testing be

performed on an appropriate number of batches at scale, based on statistical

analysis and/or risk assessment. For final diafiltration/formulation buffers,

endotoxin testing is recommended to be performed prior to use to assess the

buffer’s microbial quality for all batches.

All buffers which are not filtered (e.g. non-filterable buffers) should be freshly

prepared and used as soon as possible. Bioburden and endotoxin

sampling/testing for non-filtered buffers is recommended to be performed for all

batches prior to use (buffers used for cleaning/sanitization steps may be

excluded), unless a risk based assessment justifies another approach (e.g.

buffers prepared immediately prior to use, or buffers that are not growth

promoting). For buffers that are stored for longer than 24 hours, a hold time

validation (including bioburden and endotoxin data) are expected.

Inoculum Expansion Operations

Prior to transferring from passive control (i.e. passive control of pH and dissolved

oxygen) inoculum expansion to the first active control expansion step, at full

scale, a bioburden sample may be taken. This sample is in addition to routine

visual examination for viability and absence of microorganisms or purity check

(for microbial processes). Given potential contamination risks and sample

volume concerns associated with sampling at earlier inoculum expansion stages

(Erlenmeyer flasks, roller bottles, etc.) sampling for bioburden is not

recommended. Endotoxin testing is not routinely performed at inoculum

expansion stages.

Testing for bioburden of the final culture from passive control inoculum

expansion to the first active control expansion is recommended on an

appropriate number of batches at scale based on statistical analysis and/or risk

assessment.

NOTE: To support potential contamination investigations, some companies

collect and retain samples at the end of each expansion operation until batch

release.

Bioreactor (Inoculum and Production) Operations

Prior to transfer into the next bioreactor, a bioburden sample may be tested or

kept as a back-up sample (perform a purity check in the case of microbial

processes). For inoculum bioreactors, consider testing the pre-transfer culture

for bioburden on an appropriate number of batches at scale based on statistical

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analysis and/or risk assessment. In the case of production bioreactors, all

batches should be tested for bioburden at the end of production (unprocessed

bulk sample). Endotoxin testing is not routinely performed at inoculum

expansion stages since these stages are expected to be essentially sterile.

For continuous cell lines, bioburden samples should be taken in order to

reflect the individual manufactured batches

Harvest Operations

Clarified harvest pool (filtered or unfiltered) at the end of harvest operations

should be tested for bioburden/endotoxin for all batches just prior to the start of

the following process step. Only in the case when clarified harvest is filtered

into a pooling tank, is it recommended to test the clarified harvest prior to

filtration for bioburden for an appropriate number of batches at scale based on

statistical analysis and/or risk assessment. This provides adequate evaluation

of bioburden control for the harvest operation (sampling pre-filtration should be

performed as close as possible to the end of the harvest operation).

Chromatography and Ultrafiltration/Diafiltration (UF/DF) Operations

To evaluate column and UF/DF performance during operations it is

recommended that bioburden and endotoxin testing be performed on an

appropriate number of batches at scale, based on statistical analysis and/or risk

assessment at the following steps:

○ WFI rinse (at retentate or drain line) following removal of storage solution (if

system is stored wet). This is a valuable sample points for evaluating column

and resin storage effectiveness.

○ WFI rinse following pre-use sanitization step (prior to the start of equilibration

phase). This is a valuable sample points for evaluating column and resin

cleaning effectiveness.

○ Equilibration buffer at the end of membranes equilibration step (prior to the

start of product concentration phase)

Note: Some events have shown that microorganisms can be bound to the

resin during equilibration phase and elute with wash/elution buffers).

○ WFI rinse following post-use cleaning/sanitization step (prior to start of

storage phase)

Each protein pool (filtered or unfiltered) at the end of chromatography and UF/DF

operations should be tested for bioburden and endotoxin. When the protein pool

is filtered into a pooling tank, the protein elution is recommended to be tested for

bioburden prior to filtration. This ensures adequate evaluation of microbial

control of the chromatography and UF/DF operations (sampling pre-filtration

should be performed as close as possible to the end of the final elution step).

Microbial control of reusable filters, resin storage conditions of new and unused

resins, and resin stored in columns, should be demonstrated and validated.

Resin storage conditions should be tested for bioburden to demonstrate

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bacteriostatic conditions. Acceptance criteria for these samples should be set

using the vendor’s specifications for new and unused resins (typically ≤100

CFU/mL).

Bulk Dispensing Operations

Bioburden and endotoxin samples should be taken from the final bulk drug

substance (post filtration). There are many different configurations for bulk

filling operations. The bioburden/endotoxin samples collected should be

representative of the operation, taking into consideration the risk associated

with sampling, and the nature of the filling operation (e.g. closed vs open filling;

single container vs multiple containers).

Microbial Test Methods

Endotoxin testing can be performed using any of the approved compendial

methods, although the kinetic chromogenic/turbidimetric techniques are

recommended as these methods are more precise and data interpretation is

automated.

Bioburden testing can be performed using any of the approved compendial

methods or validated rapid microbial methods using at least 10mL samples and

should be conducted in a suitably controlled environment to minimize the

potential for laboratory introduced contamination. Given the matrix

characteristics of bioreactor samples, it may be necessary to use more than

one filter to process a 10mL sample (e.g. 5 filters with 2 mL sample on each

filter). Use of validated rapid microbial methods is recommended to reduce

time to results which enables quicker responses to microbial excursions.

NOTE: Suitability testing should be performed using cultures from a recognized

culture collection (e.g. ATTC) and environmental microorganisms for each

sample matrix or family of sample matrixes to ensure the ability to recover low

levels (<100 CFU) of microorganisms.

Additionally, laboratory managers need to ensure that bench microbiologists

are adequately trained to differentiate between bacteria, yeast and molds, as

well as the presences of spreaders/confluent growth of microbes.

Microbiologists should also be able to distinguish macroscopic colonial types

by morphology (with or without magnification). If there is a frequent recovery of

spreaders/confluent colonies, the laboratory may need to read the samples on

a daily basis to determine an accurate estimation of the bioburden level.

Plate count recoveries exceeding 250 CFU on the most dilute sample are

reported as Too Numerous to Count (TNTC). A TNTC result for any in-process

bioburden sample should automatically result in an Action Level or Out Of

Specification (OOS), which requires an investigation. A TNTC recovery on an

in-process bioburden sample should be a rare occurrence due to measures

taken to prevent/minimize bioburden contaminations from occurring in

biologically manufactured products. A valid TNTC result indicates that there

has been a potential breach to the manufacturing controls put in place to

prevent contamination from occurring. Investigations initiated in response to

TNTC results need to be robust and thorough to ensure patient safety.

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In the case of microbial processes, the testing used at the end of the

production bioreactor is typically a Purity test to confirm absence of non-host

microorganisms by plating on selective and non-selective media and visual

examination. The microbial purity method should also be validated using spike

recovery studies. The spike recovery studies should be performed using

samples containing host cells at a viable titer that is representative of the

process.

Setting Bioburden Control Levels (Alert/Action)

Unlike non-sterile dosage forms, there are no recommended bioburden levels

provided in regulatory guidelines or compendia for the protein purification processes

of biologic or other biopharmaceutical products, therefore, manufacturers are

responsible for setting bioburden control levels for biologic production processes.

The BPOG Bioburden Working Group conducted a member survey of bioburden

action levels and found that the majority of biologic processes action levels were set

between 1-10 CFU/mL. When control levels (i.e. action and/or alert levels) are set

appropriately, drifts or deviations from normal operating conditions can be promptly

detected, investigated and remediated. When control levels are not set appropriately

(e.g. too loose or too tight), a loss of microbial control may go undetected, or

unnecessary investigations may be performed. Therefore, setting appropriate control

levels is a key component of a successful microbial control strategy.

Since control levels are set prior to product licensure, they are often set with limited

data; or are based on comparable processes until enough data can be attained

reflecting process capabilities. After commercialization, additional data will be

available and periodic review is required to ensure control levels reflect process

performance over time. Consideration should be given to correlate results of

bioburden testing to results of routine environmental monitoring of the manufacturing

facility and equipment. Review of control levels should be proceduralized to ensure

consistency across the manufacturer’s product portfolio.

Objectionable Organisms

The concept of objectionable organisms is applicable to non-sterile drug products

because viable microorganisms may be delivered to the patient. However, this

concept is not applicable to biologics manufacturing of sterile drugs because no

microorganisms are allowed in the final dosage form. Furthermore, creating a list of

objectionable organisms for biologic in-process samples may actually limit the scope

of investigation and keep objectionable manufacturing conditions from being

assessed and addressed.

Unlike non-sterile drug manufacturing where the processing environments are often

hostile to microbial growth or include the addition of preservatives, manufacturing of

biologics require growth mediums (upstream cell culture steps) that enhance

bacterial growth or process buffers (downstream protein purifications steps) that are

often bacteriostatic. Due to these manufacturing environments bioburden levels in

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biologics must be controlled to and reach near sterile conditions in upstream process

steps and ≤ 10 CFU/mL during downstream processing.

Responding to Bioburden Excursions

When bioburden control levels are exceeded, an investigation with the rigor

commensurate with the risk (e.g. action level vs alert level excursion) should be

conducted. To ensure adequate and consistent responses to bioburden control level

excursions and adverse trends (variation from the historical mean over time),

manufacturers should establish written procedures for the investigation of these

events. The following are recommended actions to take in response to control level

excursions:

Adverse Trends:

When adverse trends are noted they should be investigated, using at minimum, a

comparable approach as action level excursions (see below).

Alert Level Excursions:

Alert levels are set to monitor process performance and provide early warning of

an adverse trend or action level excursion. As such, the following actions are

recommended:

Initiate an investigation record in the quality system

Review historical data for adverse trend

Identify microorganisms to species level, if possible, for microorganism

trending purposes

Notify affected departments and Quality Assurance and/or as defined by local

procedures

Action Level Excursions:

Action levels are set to ensure the process is operating as designed, and require

investigation and remediation if not met. In addition to the actions required for alert

level excursions the following actions are recommended to determine the cause of

the excursion, evaluate the significance of the excursion in the contexts of other data,

and to initiate action to restore intended operating conditions.

Initiate an investigation record in the quality system

Obtain feedback from a cross-functional investigational team (e.g.

Manufacturing, Quality Control, Quality Assurance, Facilities, Engineering,

etc.)

Perform concurrent laboratory and manufacturing investigations

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Determine root cause (e.g. review utilities; compressed gases and WFI

systems;, equipment maintenance, engineering changes, environmental

monitoring, training, etc.)

Assess potential product quality impact

Implement corrective and preventive actions (CAPA)

Perform CAPA effectiveness check; where appropriate

NOTE: Bioburden excursions that meet or exceed the action level do not necessarily

indicate that product quality has been compromised but do indicate the need to

investigate. Consider conducting a risk assessment to evaluate if the process should

be halted pending resolution of the issue and completion of a “return to service” plan.

When bioburden action level excursions or adverse trends are noted, product safety

and product stability need to be assessed. The following information can be used for

this assessment, in addition to other factors:

What organism(s) was recovered? When possible, identify the species level.

Is the disinfectant procedure effective at removing the recovered organism, if

applicable?

What toxins and/or microbial byproducts does the organism(s) produce or

release?

What stage in the process did the excursion occur?

What downstream purification steps were performed after the organism(s) was

recovered? Are the purification steps validated to remove bioburden? Is there

data that supports clearance of the possible microbial byproducts?

Are there any connections or links to other bioburden excursions in either

upstream or downstream processes?

Have the same organism(s) been observed during the production of the previous

lot?

How long was product held at the step (residence time of organism) where the

excursion was detected and at what temperature and at which pH?

Were changes made to the manufacturing process (e.g. equipment

modifications) prior to the excursion(s)?

What potential impact could the recovered organism(s) have on the

manufactured protein?

What is the impact of the microbial byproduct production (toxins) on the patient

or product safety? Is there stability data that would provide assurance that the

drug substance or drug product has not been impacted?

Are all In-Process Control (IPC) results within historical trends and does the drug

substance meet all release specifications?

What information was gathered from literature searches and/or during studies

conducted during the investigation?

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Assessing Impact to Product Quality

Assessing residual microbial byproducts related to patient and product safety

EXAMPLE 1

For Adverse Trends or Action Level excursions, the following areas should be

assessed and may be included in an investigation:

Perform laboratory investigation, which should include but is not limited to, the

review of analyst’s training, calculations, negative controls, sampling handing,

and test materials.

Review HVAC performance in the respective manufacturing area i.e. last filter

certification reports, differential pressures for date under investigation, and

trend history.

Review environmental monitoring and critical utility data for the respective

manufacturing area.

Review work order system to examine operation of equipment for anomalies

(e.g. belt grinding and producing elevated total particulates).

Review cleaning and sanitization of the impacted area, including agents used,

their preparation, and their effectiveness against the recovered organism (s).

Review any changes to the facility, utilities (e.g. compressed gases and WFI

systems), equipment (e.g. chromatography skids, column packing operations,

etc.) or process (e.g. logbooks and work orders).

Review batch record for any interventions that may have contributed to the

excursion(s).

Conduct interviews of the personnel involved i.e. manufacturing associates

and laboratory analysts.

Confirm microbial identification to the species level. If the organism is the

same as previously recovered in the process, perform strain typing to

determine if it is from the same source.

Conduct a literature search on the recovered microbe to determine the worst-

case toxin that might impact patient safety and publish in peer reviewed

journals.

Determine if the organism strain recovered has the gene encoding the worst-

case toxin.

Determine if the worst-case toxin is expressed in the specific condition in

which the recovered microbe was isolated.

ADDITIONAL SUGGESTIONS:

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o Determine if the level of the worst-case toxin in subsequent

processing unit operation(s) can be reduced using a scale-down

model.

o When there is not an identifiable worst-case toxin, use a surrogate

toxin (protein) for data gathering and risk assessment.

For bulk drug bioburden excursions perform filtration risk assessment of the

product specific validated retention capacity to calculate safety factor.

EXAMPLE 2 (Model developed by Roche)

Though bioburden is easily removed by filtration steps during the purification

processes, Residual Microbial Byproducts may possibly be co-purified with the

product and have detrimental effects on patient and product quality. Quality impact

assessments should include the following:

Criticality of the process step

o Excursions during cell culture are not acceptable, and if contamination is

confirmed, the batch should be rejected.

Review of trend data

o Ensure data provides assurance that there is no systemic failure or

evidence of biofilm.

Assessments of Microbial Byproducts that can have adverse effects on patient

safety. These are primarily:

o Exotoxins:

Protein Exotoxins (e.g. Botulinum Toxin A

Non-Protein Exotoxins (e.g. Aflatoxin)

o Endotoxin

o Flagellin

o Microbial DNA

o Cell wall polysaccharides

With the exception of endotoxin, there are no available GMP assays to detect

these Microbial Byproducts. However, worst-case calculations of the levels of

these components can be performed and compared to a specific safety level

using the following:

o Identity of the contaminant(s). Identification by genotypic methods is

highly recommended.

o Literature search on the contaminants for cell size and known exotoxins.

o The level of the contamination (CFU/mL).

o Concentration of the Drug Substance.

o Maximum dosage.

An example of such a calculation is as follows:

Scenario: A downstream purification pool is contaminated with 100 CFU/mL of

Bacillus cereus.

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Assumptions:

Protein Concentration of the Drug Substance: 22.5 mg/mL.

Dosing: Product has a maximum dose of 750 mg

Calculated value Result Detailed calculation

Volume of single cell

(Bacillus cereus) 37.7 µm3

(max cell radius)2 × π × (max cell

length) = 1 µm2 × π × 12 µm

Moist mass of single cell 37.7 pg Density of bacterial cell = 1

g/mL

Total moist mass in

contaminated downstream

processing sample

3770 pg/mL 37.7 pg ×100 cells/mL

(= 100 CFU/mL)

Total dry mass (B. cereus) 1131 pg/mL 30% of 3770 pg/mL

Total protein content (B.

cereus) 622.05 pg/mL

Proteins present 55% of total dry

mass

Fraction of protein

exotoxins

0.311025

pg/mL

Protein exotoxins present 0.05%

of total bacterial protein content

Number of doses per mL 0.03 22.5 mg/mL drug substance ÷

750 mg

Potential protein exotoxin

contamination per dose 10.3675 pg 0.311025 pg/mL ÷ 0.03/mL

Potential protein exotoxin

contamination per kg body

weight per day

0.20735 pg 10.3675 pg ÷ 50 kg body

weight

Factor of potential protein

exotoxin contamination

below TDLo* of Botulinum

Toxin Type A

5.8 1.2 pg/kg ÷ 0.20735 pg/kg

*TDLo = Toxic dose low. The lowest dose of a substance which, whatever the

dosage form and over an indeterminate time period, causes a documented toxic

effect in humans (RTECS Guideline, US Dept. of Health and Human Services).

Conclusion: A contamination event of a downstream purification pool with 100

CFU/mL of Bacillus cereus resulted in a potential toxin contamination that is below

the TDLo of Botulinum Toxin Type A by a factor of 5.8 and therefore does not have

an impact on patient safety.

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Conclusion:

This paper provides recommendations from a biopharmaceutical industry perspective

on microbiological monitoring of in-process intermediate products, including drug

substances. Additionally, recommendations on subjects commonly encountered in

the establishment of a monitoring program, such as setting alert/action levels,

objectionable organisms in bulk biologics, responding to bioburden excursions and

assessing impact to product quality, are included.

These recommendations assist biologic manufacturers in refining their current

microbial control strategy, as well as developing control strategies for new processes

and products. Establishing appropriate microbial control levels provides indications

of the effectiveness of the manufacturing process.

Responding to bioburden excursions can be difficult and are often inconsistent within

the same company. This paper provides information that can be used to develop an

investigational checklist that will help drive consistent and thorough investigations,

and provides examples for assessing impact to product quality when bioburden

excursions occur. To ensure consistent impact assessments and successful

regulatory review of microbial excursions, formal impact assessment models are

recommended. .

An important aspect of all impact assessment models is the treatment of

objectionable organisms. The BPOG members that contributed to this paper believe

the concept of objectionable organisms is not applicable to biologics; since all

organisms recovered in in-process and drug substance samples should be identified

to species level, and trended and investigated thoroughly when recovered above the

action level. Furthermore, final drug product formulations are sterile which greatly

reduces the risk of delivering microbes to the patient.

In the future, the BPOG Bioburden Working Group will use this paper to present an

Industry perspective on microbial monitoring and control of biologic manufacturing

processes to regulatory agencies to gain their acceptance and to influence future

regulations of non-sterile bulk biologic manufacturing.

References

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Biotechnological/Biological Products; International Conference on Harmonisation:

1999. www.ich.org (accessed June 24, 2014).

2. Quality Guideline Q7A: Good Manufacturing Practice for Active Pharmaceutical

Ingredients; International Conference on Harmonisation: 2005. www.ich.org

(accessed June 24, 2014).

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3. Technical Report No. 33: Evaluation, Validation, and Implementation of Alternative

and Rapid Microbiological Methods; Parenteral Drug Association: 2013.

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Union, Volume 4 EU Guidelines to Good Manufacturing Practice Medicinal

Products for Human and Veterinary Use. Brussels, 25 November 2008.

www.ec.europa.eu

7. von Wintzingerode, Friedrich "Biologics Drug Substance Production: Safety

aspects of bioburden contaminations of non-sterile process intermediates" ECA,

European Microbiology Conference, Copenhagen, April 24-25, 2013

Acknowledgements

We thank the following for their help and support: Marc Kinnelly of Astra Zeneca,

Bastian Omokoko and Eileen Economy of Bayer, Barbara Daddis of Bristol-Myers

Squibb, Jeri Bonilla of Genentech, Jay Stout and Beth Junker of Merck, Cheryl Mowen

of Novavax, Randall Thompson and Cathleen O’Connor of Shire, Friedrich von

Witzingerode of Roche, Jose A. Marrero of AbbVie and David Bain of the BioPhorum

Operations Group (BPOG).


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