Cleaning Validation for Biopharmaceutical Manufacturing at Genentech

ABSTRACT
Biopharmaceutical manufacturing and cleaning equipment must be designed for effective and consistent cleaning to avoid cross-contamination and the cleaning processes must be verified as effective. A cleanability study is essential before introducing a new product into the manufacturing equipment. Part 1 of this article provides background on cleaning validation and the associated regulations, cleaning methods, and the validation strategy. It also describes Genentech's approach for new product introduction using laboratory-scale and representative-scale studies. Part 2 will cover the other aspects of the cleaning validation program such as grouping strategy, validation sampling, acceptance criteria, change control, and revalidation.

Cleaning validation refers to establishing documented evidence providing a high degree of assurance that a specific cleaning process will produce consistent and reproducible cleaning results that meet a predetermined level. A cleaning program can be divided into three phases: cleaning process and cycle development, cleaning validation, and maintenance. The program should begin with equipment design evaluation and cycle and process development that includes, but is not limited to, the following: sanitary equipment design, selection of final rinse water, approved equipment specifications that address an evaluation of the compatibility of construction materials with product and cleaning solutions, sprayball design optimization, cleaning process design studies, cleaning sample assay validation, suitability of sampling, and recovery studies for assay and sampling methods. Without these design and development activities, validation could potentially lead to unnecessary troubleshooting and cleaning verification exercises.

The cleaning process should remove materials such as media, buffers, storage solutions, cell culture fluids, cell debris, non-active pharmaceutical ingredients containing placebos, and formulations and concentrations of drugs or active pharmaceutical ingredients (API). Selection of appropriate sampling to demonstrate that residues have been removed to an acceptable level is vital for the success of cleaning validation.

At Genentech, Inc., design and cleaning-cycle development is considered a prerequisite for cleaning validation. The purpose of cleaning validation at Genentech for biopharmaceuticals is to:

• Assess a new product or new equipment for cleanability before cGMP production.
• Ensure that cleaning procedures are adequate for cleaning new products or new equipment.
• Ensure that residues after cleaning of equipment are reduced to an acceptable level before the manufacture of the next run or the next product in the same equipment.
• Provide ongoing assurance that the validated cleaning procedures are in a state of control through monitoring and periodic revalidation.
• Evaluate and validate changes to cleaning processes, other manufacturing processes, and equipment to maintain these validated cleaning processes in a state of control.

REGULATORY EXPECTATIONS

Cleaning validation is driven by regulatory expectations to ensure that residues from one product will not carry over and cross-contaminate the next product. An effective cleaning program starts with appropriately designed equipment and cleaning processes, followed by validation and maintenance. The following are some good manufacturing practice (GMP) cleaning validation requirements for the biopharmaceutical industry.

US Food and Drug Administration 21 CFR Part 211: Current GMP for Finished Pharmaceuticals

§ 211.63 Equipment design, size, and location:
Equipment used in the manufacture, processing, packing, or holding of a drug product shall be of appropriate design, adequate size, and suitably located to facilitate operations for its intended use and for its cleaning and maintenance.¹

§ 211.67 Equipment cleaning and maintenance:
(a) Equipment and utensils shall be cleaned, maintained, and sanitized at appropriate intervals to prevent malfunctions or contamination that would alter the safety, identity, strength, quality, or purity of the drug product beyond the official or other established requirements. (b)(3)(5) Protection of clean equipment from contamination before use.¹

§ 211.182 Equipment cleaning and use log:
A written record of major equipment cleaning, maintenance, . . . and use shall be included in individual equipment logs that show the date, time, product, and lot number of each batch processed.¹

Basic European Union GMP Requirements for Medicinal Products
EudraLex, volume 4, Medicinal Products for Human and Veterinary Use: Good Manufacturing Practice, chapter 3, Premises and Equipment:
Principle: Premises and equipment must be located, designed, constructed, adapted, and maintained to suit the operations to be carried out. Their layout and design must aim to minimize the risk of errors and permit effective cleaning and maintenance to avoid cross-contamination, build up of dust or dirt and, in general, any adverse effect on the quality of products.²

EudraLex, volume 4, Medicinal Products for Human and Veterinary Use: Good Manufacturing Practice, annex 15, Qualification and Validation:
Cleaning Validation: Cleaning validation should be performed in order to confirm the effectiveness of a cleaning procedure. The rationale for selecting limits of carry over of product residues, cleaning agents, and microbial contamination should be logically based on the materials involved. The limits should be achievable and verifiable.²

International Conference on Harmonization Q7, Good Manufacturing Practice Guide for Active Pharmaceutical Ingredients
The ICH Q7 was developed jointly by the European Union, Japan, and the United States for active pharmaceutical ingredient manufacturing.³ API is the drug substance before final formulation; section 12.7 contains cleaning validation requirements for APIs.

Other Guidance Documents
Additional guidance documents have been established by regulatory agencies and industry associations, such as the FDA, the Pharmaceutical Inspection Convention and Pharmaceutical Inspection Co-operation Scheme (PIC/S), the Canada Health Products, and the World Health Organization .^4–7

BIOPHARMACEUTICAL MANUFACTURING PROCESSES AT GENENTECH

Genentech manufactures biopharmaceutical products from E. coli and Chinese hamster ovary host cells using multiproduct, dedicated, and single-use equipment. Product manufacturing involves cell culture and bacterial fermentation processes, with the associated recovery processes (harvesting, initial and final purification), followed by formulation, aseptic filling or lyophilization, and capping.

Genentech's manufacturing processes include steps for manufacturing and purification of the API, and steps for manufacturing and packaging of the finished drug product. Steps up to and including final purification of the drug substance are considered API manufacturing; the formulation of the drug substance into finished product and the packaging of that product is considered finished drug product manufacture. This is consistent with regulatory expectations for these different categories of manufacturing, with cleaning validation requirements including predetermined acceptance criteria, which may differ for each type of manufacturing. Two separate cleaning validation master plans have been created: one for the API and one for the finished drug product.

CLEANING METHODS

Cleaning is performed to remove materials introduced into equipment during the manufacturing process. These materials may include media, buffers, storage solutions, cell debris, non-API-containing placebos, and any formulation or concentration of a given drug product or API. Manufacturing and cleaning equipment must be designed for effective and consistent cleaning. The cleaning of manufacturing equipment surfaces at Genentech uses automated, semi-automated, and manual cleaning processes. For larger, enclosed equipment, an automatic or semi-automatic clean-in-place (CIP) process is typically used. Cleaning process parameters include cleaning agent concentration, temperature, flow rates, volume, and time.

Equipment cleaning procedures use cleaning agents to aid removal of process soils. The cleaning agents may be categorized as caustic, acidic, neutral, or oxidizing. Some equipment at Genentech is cleaned with water for injection only, using no cleaning chemicals. A typical CIP process includes an initial water pre-rinse, a washing step with one or more cleaning agents, and a final rinse. Before conducting residue removal testing in cleaning validation, installation qualification and operational qualification are performed on the equipment to be cleaned and on the equipment used for the cleaning process. Manufacturing equipment is exposed to cleaning solutions by fully submerging the component (i.e., clean-out-of-place washer or manual cleaning methods); by fully flooding the product-contacting surfaces (i.e., transfer lines or manually cleaned tanks); or by directing fluids by use of spray devices such as spray balls, spray wands, and washer nozzles.

For equipment containing a spray device, qualifications include identifying and documenting the device, noting its proper orientation and alignment, and performing a spray coverage test to assure complete coverage. Spray device coverage verification testing for vessels that are cleaned in place is conducted according to an approved procedure. This procedure involves the use of a visual marker (e.g., riboflavin solution, which fluoresces under ultraviolet light) and spray devices. For glassware that is cleaned in washers, verification of coverage may be conducted with process soils, rather than riboflavin, if process soils are readily visible against translucent glass surfaces.

CLEANING VALIDATION STRATEGY

The cleaning processes for product-contact surfaces for all products manufactured in GMP equipment must be demonstrated to be effective. Product-contact surfaces are surfaces that make direct contact with product or materials introduced into equipment as part of the normal manufacturing process by their very design. Indirect-product-contact surfaces (such as buffer tanks), where there is a significant risk of residues on surfaces contaminating a subsequently manufactured product, also undergo cleaning validation.

To demonstrate the effectiveness of a cleaning process, the process is challenged. This challenge involves at least three consecutive successful cleaning process runs, after which residues are measured and results are compared to predetermined acceptance criteria.

Mock soiling is also used. Mock soiling refers to the soiling of equipment by a process other than routine manufacturing that creates a dirty equipment state equivalent to that following routine manufacturing. Mock soiling of equipment for validation purposes can be performed when equipment is not available for manufacturing soiling. Mock soiling procedures must be adequately described to simulate normal manufacturing processes.

Cleaning validation includes the establishment of dirty hold times and clean hold times. Dirty hold time is the amount of time between the end of the use of the equipment and the start of equipment cleaning. Clean hold time is the amount of time between the completion of the equipment cleaning and the next cycle of use. Cleaning processes are challenged for maximum dirty hold times during cleaning validation runs.

For clinical products, infrequently made products, or infrequently used equipment, a cleaning verification approach may be used in lieu of cleaning validation.

Single-use product-contact equipment (used once and then discarded) is excluded from cleaning validation. Single-use items include beakers, pipettes, weigh boats, silicone tubing, sample tubes, storage bags, and normal-flow filtration filters.

Product-dedicated refers to equipment that is used for a single product and then is removed as part of changeover procedures. Product-dedicated items, such as chromatography resins and tangential-flow filtration membranes, are used with one product only. The requirement for residues in dedicated equipment may differ from that for residues in equipment used for multiple products; nevertheless, the cleaning of product-contact surfaces of dedicated equipment requires cleaning validation. The validation of product-specific resin and membrane cleaning is captured in process validation protocols.

Multi-use equipment may be used to process one or more products or media components. At Genentech, the main emphasis of the equipment cleaning validation program is on multi-use equipment, because this equipment type has the highest risk of process contamination (run-to-run or product-to-product).

NEW PRODUCT INTRODUCTION

Before introducing a new product into equipment used for manufacturing a marketed product, a cleanability study is performed to determine the effectiveness of the cleaning process, using the new product on similar equipment surface types. The new product introduction (NPI) method has two purposes: to avoid cross-contamination of commercial products, and to collect development data on new products.

The cleanability study is divided into two parts: the laboratory-scale study, and the representative-scale runs. The cleanability study starts with an evaluation of the characteristics of the product and soiling at laboratory scale to determine the effectiveness of the rinse, swab, and visual inspection methods. Results of the laboratory-scale study are verified at representative scale. Representative-scale runs include three successful consecutive cleaning runs, conducted on equipment used for marketed products, which include sampling and analysis for residues, and comparison to predetermined acceptance criteria.

Laboratory-Scale Study
As part of sampling suitability testing, process residues of the new product are evaluated for recoverability by rinse and swab sampling methods. In this study (also known as recovering organic carbon by rinse and swab) total organic carbon (TOC) is analyzed to determine the sampling method that is appropriate for cleaning validation testing.

Soils from fermentation, initial purification, and final formulated bulk are used in this study. Testing is performed on each surface type (e.g., stainless steel and glass). Before spiking, soils are adequately mixed before use (by gentle inverting of the sample tube for fermentation soils or by vortexing for recovery soils). Coupons are prepared (cleaned and dried) and are spiked with protein soils at TOC concentrations similar to those in the cleaning validation acceptance criteria limit. The soiled coupons are dried for at least 24 hours, or for the specified dirty hold time, and are sampled using the rinse or the swab method. Positive and negative controls are generated, and swab and rinse water recoveries are calculated.

For highly soluble proteins, the average results of rinse and swab sampling recovery studies for fermentation, initial purification, and final bulk soils usually vary between 80% and 120%. If average recovery results for rinse or swab sampling methods is outside the acceptable range, an investigation is undertaken and a correction factor is applied for less-than-minimum recovery when reporting the equipment validation TOC results. WHO has set the following recovery levels: greater than 80% is good; greater than 50% is reasonable; and less than 50% is questionable.⁷ However, the key to recovery is consistency between samples, not just total recovery.

Representative-Scale Runs
The overall study challenges the ability of the standard cleaning procedure to remove the new product soil from representative equipment surfaces.

The cleaning process is challenged by including the maximum dirty equipment hold time.

The cleaning process may also be challenged by reducing one or more cleaning process variables—such as cleaning time, flow rate, or volume—during each run.

Sampling for residues includes rinse sampling, swab sampling, and visual inspection. An evaluation is performed to determine suitability of swab and rinse methods for validation sampling.

Results
The product residue acceptance criteria in a cleanability study are calculated using the same principles and calculations as for a validation protocol for equipment used to make marketed products. Acceptable results in the cleanability study allow a new product to be introduced and validated in equipment for marketed products; acceptable results also increase confidence in successful validation runs. Cleaning validation of the major multi-use product-contacting equipment is executed concurrent with manufacturing. Acceptable results in triplicate runs of a cleanability study in one facility constitute an acceptable basis for introducing the product into the same combination of equipment configurations and product-contact surface types in any other facility, after equivalence of equipment, cleaning methods, sampling, and acceptance criteria has been established. This equivalency should be documented in the validation protocol or in a technical report. Currently, data from full-scale cleaning validation and new product introduction methods are being generated at Genentech to determine worst-case situations and to justify reduced testing.

CONCLUSION

Cleaning validation is driven by regulatory requirements to ensure that residues from one product will not carry over and cross contaminate the next product. Appropriate design of cleaning equipment and cycle development increases success rate and reduces validation execution time. At Genentech, the cleaning program consists of equipment design and qualification, cleanability study, sampling evaluation, and meeting predetermined validation protocol acceptance criteria. Dirty and clean hold times are established during cleaning validation. Cleaning validation is supported by approved procedures and by training programs for personnel who perform the cleaning operations in the production areas and who collect validation samples. Part 2 will discuss implementation of the cleaning validation program—grouping strategy, various types of sampling and their acceptance criteria, training, change control, and revalidation.

ACKNOWLEDGEMENTS

The author is thankful to corporate quality management at Genentech, Inc., for support, and to Jenna Carlson and Ahmed Bassyouni for reviewing the manuscript and providing comments.

A. Hamid Mollah, PhD, is a senior technical manager for corporate quality and validation at Genentech, Inc., South San Francisco, CA, 650.467.1095, mollah.hamid@gene.com
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REFERENCES

1. US Food and Drug Administration. Guidance for industry. Current good manufacturing practice for finished pharmaceuticals. Rockville, MD; 2006 Apr.

2. European Commission, Enterprise Directorate General. EudraLex, vol.4, Medicinal products for human and veterinary use: Good manufacturing practice. Office for Official Publications of the European Communities: Luxembourg; 2007 Mar.

3. International Conference on Harmonization. Q7, Good manufacturing practice guide for active pharmaceutical ingredients. Geneva, Switzerland; 2000 Nov.

4. US Food and Drug Administration. Guide to inspections of validation of cleaning processes. Rockville, MD; 1993 July.

5. Pharmaceutical Inspection Convention and Pharmaceutical Inspection Co-operation Scheme. Validation master plan installation and operational qualification: Non-sterile process validation. Cleaning validation. Geneva, Switzerland; 2004 July.

6. Canada Health Products and Food Branch Inspectorate. Guidance Document. Cleaning validation guidelines: Drug and health products. Health Canada: Ottawa, Canada; 2002 Spring.

7. World Health Organization. Supplementary guidelines on good manufacturing practices: Validation. Geneva, Switzerland; 2005.