20.10.2011

FDA Q&As on pathogenic Contamination of animal-derived Drug Ingredients

On FDA's website with "Questions and Answers on Current Good Manufacturing Practices, Good Guidance Practices, Level 2 Guidance - Control of Components and Drug Product Containers and Closures ", some new questions about the risks, preventive measures and minimizing of contamination of animal-derived drug ingredients were published.

1.What are FDA’s primary concerns about pathogenic agent contamination of animal-derived drug ingredients?

The FDA is concerned about contamination of animal-derived ingredients by pathogenic agents during processing at the LPE, at a subsequent consolidator of animal material or raw material processing plant, or during the manufacturing process to create the final ingredient. One should assume that animal-derived materials will not only harbor but often support growth of pathogens, and accordingly should assure appropriate control over the handling and processing of these materials. Current good manufacturing practice (CGMP) is to be followed in handling such material to assure that contamination does not occur that would affect the material’s quality and purity, or that would be harmful when the product is administered to patients. Pathogenic agent contamination includes bacteria, molds, viruses, protozoa, parasites, and prions. Pathogenic agents can enter the manufacturing facility within the animal material, and contaminate excipients, water, processing equipment, personnel, environment, or packaging. Contaminated drug ingredients present potential health risks that may affect various patient populations, including immune-compromised patients, as well as otherwise healthy people of all ages.

An agent may be considered pathogenic if its presence represents a significant risk to patient safety. Factors affecting the pathogenic agent’s ability to cause harm include:

the nature of the agent (pathogenicity, virulence),
the amount of pathogenic agent,
the type of manufacturing process and whether it affects the pathogenic agent’s ability to survive,
the ability of the pathogenic agent to grow within the ingredient,
the type of drug product and its route and length of administration, and
the patient population (including the most vulnerable patients that may take the drug) for the drug product.

2. What manufacturing contamination risks are presented by the different pathogenic agents?

Manufacturing contamination risks presented by the different pathogenic agents can include the following:

Vegetative Bacteria
Vegetative bacteria are actively growing and reproducing bacteria. If there are no steps in the manufacturing process to kill vegetative bacteria, they can proliferate and accumulate during drug ingredient processing.

Toxin-Producing Microorganisms
Several genera and species of microorganisms are capable of producing toxins. Microbial toxins can be divided into two general groups: exotoxins and endotoxins. An exotoxin is a soluble protein excreted by a microorganism, including bacteria, fungi, algae, and protozoa. Exotoxins can include heat-stable toxins that remain active at temperatures as high as 100°C or heat-labile toxins that are readily inactivated by heat treatment. Exotoxins, especially heat-stable exotoxins, can remain in the ingredient throughout the manufacturing process and adversely affect patient health. An endotoxin is a component of the outer membrane of a Gram-negative bacterium. Unlike exotoxins, endotoxins are only released when the organisms are disrupted or destroyed. Endotoxins are heat- and chemical-resistant and, if injected, may induce reactions including febrile effect, hypotension, and shock.

Spore-Forming Bacteria
Spore-forming bacteria can be difficult to eliminate from the manufacturing environment because the spores may be extremely resistant to heat, freezing, extreme pH, desiccation, and chemicals. Spore-forming bacteria can produce exotoxins and can remain dormant without nutrients for extended periods. Spores can be resistant to harsh manufacturing processes that will kill vegetative bacteria. When dormant spores are re-introduced into an acceptable germination environment they can become active reproductive vegetative cells. Once spores germinate and begin reproducing as vegetative cells, production of exotoxins can occur in a short period of time.

Fungi/Molds
Molds are a subset of fungi that reproduce by releasing spores into the air which, if they land on a moist nutrient source or animal tissue, can germinate. Some species of molds produce toxic byproducts called mycotoxins. Mycotoxins can accumulate in animal tissues, rendering the affected organs/tissues unfit for use as a source of starting material for the production of animal-derived drug ingredients. It is important to prevent molds from growing in drug ingredients and when feasible and valuable remove all molds that may contaminate such ingredients.

Yeasts, another type of fungi, can also be pathogenic or cause spoilage of an ingredient.

Viruses
Although a virus can only multiply within its host, the inadvertent use of material from virus-infected animals or contact of the drug ingredient with virus-contaminated surfaces can transmit viral particles to patients. Virus survival rates differ based on virus type and variables associated with surface materials that become contaminated. On hard, nonporous surfaces, some virus species can survive and remain transmissible for days or weeks. The probability of an animal virus contaminating an animal-derived ingredient will depend on the viral load of the raw material (e.g., tissue, glands, blood) and the viral clearance capability of the drug ingredient manufacturing process. Both of these factors should be considered when assessing the risk of viral contamination of the ingredient.

Internal Animal Parasites
Transmission of internal parasites occurs from host to host through consumption of contaminated food or water. Parasites live and reproduce within the tissues and organs of infected hosts, and are often excreted in feces. Government inspectors are trained to look for internal parasites and prevent unhealthy animals from entering the food supply. Animals deemed fit for food consumption are inspected and certified as healthy.

Prions
Protection from prion contamination includes obtaining bovine meat and meat byproducts from animals not infected with Bovine Spongiform Encephalopathy and protecting against contamination of product with high-risk tissues, especially brain and spinal cord tissue. Drug manufacturers importing bovine material into the United States should be familiar with and adhere to all import eligibility requirements and government regulations pertaining to food and drugs. It is important that farms, slaughterhouses and renderers observe government regulations prohibiting the use of unhealthy animals in the food supply. Animals deemed fit for food consumption are normally inspected and certified as healthy in many countries.

3. What are some ways to minimize pathogenic agent contamination in incoming animal-derived raw material?

The drug component and finished product CGMP guidances and regulations emphasize prevention of problems and avoidance of contamination rather than final testing or examination alone. In other words, control strategies that prevent contamination are central to CGMP, while control strategies based on testing alone do not comply with CGMPs. Raw materials from animals can have microbial pathogen health risks based on country of origin, LPE processing, transportation, and manufacturing processing. Under the right circumstances, raw material from animals can provide a suitable (e.g., nutrient-rich) environment for bacteria and mold to proliferate, or for viruses and other pathogenic agents to remain infective. If undetected contaminated raw material enters the manufacturing process, it can remain pathogenic in the product and a hazard to the consumer. The manufacturing conditions used in most ingredient manufacturing processes are often insufficient to eliminate all pathogenic agents from the ingredient. Methods of minimizing contamination of raw material with pathogenic agents may include the following:

Animal Source:
When animal-derived material is used, it is important that it be derived from healthy, disease-free animals. The occurrence of pathogens can vary greatly among different animal species. Ingredient manufacturers should understand the pathogenic risks associated with different animal species and with different organs, glands, or tissues within species. Drug ingredient manufacturers should be aware that even healthy animals can be reservoirs for pathogenic agents and improper handling can spread contamination. If improperly handled, microbial contamination can transfer to uncontaminated tissues and cause contamination.

Ensuring the health of U.S. livestock is the responsibility of many federal agencies, most of which are part of the U.S. Department of Agriculture (USDA). Animal-health and food-safety regulations are detailed in Titles 9 and 21 of the Code of Federal Regulations (9 CFR, 21 CFR). Animal health authorities in each state develop regulations that are consistent with the federal agencies, and are responsible for monitoring and controlling diseases in its domestic livestock and poultry. State inspectors ensure compliance by companies with individual state standards as well as with federal meat and poultry inspection statutes. States assist in controlling diseases through inspections, testing, vaccinations, treatments, quarantines, and other activities.

Awareness of the conditions of control and monitoring of source animals will aid in determining what animals and animal parts are appropriate for drug product manufacturing.

LPE:
Ingredient manufacturers should consider auditing the LPEs supplying raw materials to them and ensure their compliance with all federal and state government regulations. It is recommended that manufacturers develop Standard Operating Procedures and define sanitation requirements of raw materials immediately after butchering, including, for example, the following:
- chilling requirements, if indicated, including temperature ranges and how soon after butchering chilling should begin;
- chemical preservation methods, if indicated, including types and concentrations of chemical preservatives used;
- storage processes, including sanitization of containers, container type/material (stainless steel vs. food grade plastics, etc.);
- transportation criteria, including sanitization of containers, if different from storage and temperature ranges
The overall contamination of carcasses with pathogens depends on not only the prevalence and numbers of the pathogens on the hair, skin, and in the intestinal tract of the animal, but is significantly affected by the degree of cross-contamination occurring from these sources during slaughter and processing (see USDA references, below, for additional information). The FDA expects that manufacturers will establish appropriate specifications for bioburden in their in-coming raw materials.

4. Are there control measures for minimizing pathogenic agent contamination in animal-derived drug ingredient manufacturing facilities?

Yes, control measures may include the following:

Process Control:
Holding and processing times for animal-derived material should be minimized to reduce the likelihood of microbial proliferation. The process qualification studies should includes microbial sampling at multiple time points to evaluate the effects of time, temperature and processing conditions on microbial growth. Routine microbial identification will provide valuable information regarding the types of organisms present in incoming material and throughout the manufacturing process. Processing conditions can then be adjusted to help control the number and types of organisms present during the manufacturing process. Spores and many bacteria can be removed by filtration when filtration or filtration cascade systems are possible. Usually filters with a pore size rating of 0.45 micron or smaller will remove spores and many bacteria from a preparation. Viruses and many toxins are heat labile so a heat treatment should be considered early in process development. Many purification and concentration systems may have antimicrobial effects. The timing and sequence location in the process along with appropriate holding and processing times may serve to optimize the antimicrobial effects of the processes.

Development of process monitoring tests and acceptance criteria should be established during process development stage.

Facility and Equipment Controls:
Facilities can also be reservoirs for pathogenic agents. Maintaining a facility within CGMP should include but not be limited to:
- having adequately trained staff,
- using suitable quality water during manufacturing,
- having a facility design that minimizes the risk of cross-contamination,
- providing for proper storage of the ingredient
Cleaning procedures should include cleaning of facilities and equipment that ensures the removal of all raw materials between batches. Designing an effective cleaning program involves setting specific standards, understanding the facility’s microbial environmental isolates, and selecting the right disinfecting agents to inactivate isolates that may be in the product or in the environment. Ingredient manufacturers should use sporicidal agents at appropriate intervals in the cleaning schedule to destroy bacterial and fungal spores.

References:

1. Guidance for Industry, (ICH Q7), Good Manufacturing Practice Guidance for Active Pharmaceutical Ingredients

2. United States Pharmacopeia General Information Chapter <1072> Disinfectants and Antiseptics (USP33/NF 28 Reissue, 2010)

3. Prescott, Harley and Kleins Microbiology, McGraw Hill Higher Education, Boston, 2008.

4. USDA Animal and Plant Health Inspection Service / Import and Export