Ensuring That Media Components are AOF

Cell culture media manufacturers have three levels of quality control over the raw materials used in their media: basic analysis, questionnaires, and site audits. These levels are used because generally it is not feasible for media manufacturers to audit all of their raw material suppliers. Major media suppliers work with hundreds of raw material suppliers to source thousands of components and because each audit takes an average of two to three days and extensive travel, a team of full-time auditors would be required if every single supplier had to be audited.

Basic Analysis and Questionnaires

Cell culture media suppliers typically also ask their raw material manufacturers to fill out a questionnaire. The questionnaire should include questions such as:

• Is the material derived directly from an animal?
• Does the manufacturing process use any other animal-derived components?
• Does the supplier classify the manufacturing components and process as AOF?
• What enzymes and cell culture media have been used to produce the raw material?
• How is the product analyzed for quality?
• What cleaning and cleaning validation steps have been used to ensure there is no cross contamination of the product with any product of animal origin?

A questionnaire also can be used when a cell culture media supplier is unhappy with the results of a basic analysis. Having a raw material manufacturer provide additional documentary evidence that its component is AOF to either a primary or secondary level provides an additional level of assurance that the component is indeed AOF.

Questionnaires have several disadvantages, however. Questionnaires take time to complete, and there is the potential for inaccuracy. Also, even if the information provided in response to a questionnaire is accurate, it is only a snapshot in time. Good communication with a raw material supplier and using a change notification system will serve to keep the information current and robust.

Site Audits

For suppliers of large amounts of critical components of a cell culture medium (e.g., amino acids or insulin), a cell culture media manufacturer should conduct both a basic analysis and site audits to ensure that the written standard operating procedures (SOPs) are being followed by technical personnel. Many raw material suppliers follow current good manufacturing practices (cGMPs) and are ISO 9001:2000 certified; therefore SOP documentation should be readily available for inspection. A site audit is the best method of determining that a supplier of bulk raw materials really does understand its SOPs and is implementing them correctly for producing AOF materials. The audit should review batch ingredients and supporting documentation that confirms the origin of those ingredients.

In addition, a site visit provides the opportunity to ask the technical personnel in-depth questions. A direct interview reveals more than having staff send in answers to a questionnaire, which can sometimes be completed by a committee or someone other than the person in charge of process handling. Media manufacturers, just like the FDA, may use the track record of a supplier to determine the frequency of audits. This allows the media manufacturer to balance its resources against risks.

Biopharmaceutical companies are concerned about the potential for cross contamination between AOF and non-AOF manufacturing processes carried out in the same facilities. To address this concern, some modify their definition of AOF to require that AOF products be made in an area where only AOF production is performed. For many cell culture media suppliers, however, such separation is not always possible to achieve and many AOF products or raw materials are still manufactured alongside those of animal origin. To overcome this challenge, many media suppliers carry out validated cleaning and process controls to ensure there is no potential for animal product carryover, and provide information to their customers about these steps.

Country of Origin

Many manufacturers of good quality, cGMP-grade raw materials are now located around the world, including countries with emerging suppliers of media component raw materials like China and India. Components sourced from those countries are being used more frequently, especially by companies that are seeking to keep costs down while improving the level of AOF status. Other companies, however, prefer not to source from such countries. Mandating limitations on the countries from which raw materials can be imported, or requiring that all raw material suppliers be audited, however, can increase manufacturing costs. Those costs may have to be passed on in the price of the media and could mean the finished product would become prohibitively expensive.

Maintaining an AOF Media Supply Chain

When choosing a supplier of AOF cell culture media, there are a few important question to ask. For example, does the supplier have a secondary source of critical components that is equivalent to the primary source? And what steps has this supplier taken to mitigate AOF risk and the risk for back order? Many cell culture media manufacturers do not maintain large inventories of raw materials, and instead carry just enough to cover one to two months without any new deliveries of critical components. This reinforces several important recommendations about maintaining any supply chain:

• Attempt to forecast as accurately as possible, so that suppliers are not surprised by sudden increases in demand.
• Use a mitigating safety stock strategy to assist with sudden, unforecasted increases in demand.
• Avoid including specifics in regulatory filings that will leave suppliers without options to use alternative equipment or locations to make media. For example, do not indicate the serial number of a piece of equipment used to make media.
• Set specifications for the desired quality and put the burden of compliance on the media supplier (which can be audited as frequently as requested).
• Work closely with media suppliers to ensure product specifications balance risks with cost and availability.

Conclusion

The lack of industry standards around the definition of when the manufacturing process begins and ends, as well as whether an adventitious agent can remain through various AOF levels, will continue to affect perceptions of safety and patient risk. This is why the levels of AOF necessary must be considered when choosing a cell culture media supplier. If most therapeutics are only primary level AOF, then is the additional burden of evaluating secondary or tertiary level AOF components really essential? Biopharmaceutical companies that demand cost-effective, guaranteed AOF media and ingredients should determine how well their cell culture media supplier is assessing their raw material manufacturers before entering into a long term agreement.

In short, biopharmaceutical manufacturers must ensure public trust that they are maintaining the highest levels of safety for their end products. It is important to weigh actual risk when requiring levels of AOF beyond the primary level. If a critical or high-cost AOF component such as insulin is going to be used, the biopharmaceutical company is justified in specifying the assurances it needs to be confident it is getting the safety required. Following the steps a media manufacturer uses to qualify raw materials and working with the company to agree on the acceptable level of risk versus benefit (for example, willingness to accept an audited source from India that meets GMP requirements and an AOF definition at the desired level to ensure a regular supply) should help achieve desired patient safety while ensuring cost-effective availability.

Leslie E. Madigan is the global purchasing manager, Laurel Donahue-Hjelle is the director of cell culture product development, Satyam S. Nampalli is a technical area manager, and Mark J. Stramaglia is a senior product manager, all at Invitrogen, part of Life Technologies Corporation, Grand Island, NY, 716.774.6860, mark.stramaglia@invitrogen.com

REFERENCES

1. Zhang J, Robinson D. Development of animal-free, protein-free and chemically-defined media for NS0 cell culture. Cytotechnology. 2005;48:59–74.

2. Jayme DW, Smith SR. Media formulation options and manufacturing process controls to safeguard against introduction of animal origin contaminants in animal cell culture. Cytotechnology. 2000;33:27–36.

3. Keenan J, Pearson D, Clynes M. The role of recombinant proteins in the development of serum-free media. Cytotechnology. 2006;50:49–56.

4. Ladisch MR, Kohlmann KL. Recombinant human insulin. Biotechnol Prog. 1992;8:469–78.