TSE/BSE risk and regulations in pharmaceutical industry

TSE-Transmissible Spongiform Encephalopthy (also known as 'Prion disease') are a group of rare degenarative brain disorders characterized by tiny holes that gives the brain a spongy appearence.These holes can be seen when brain tissues  are viewed under a microscope.This  rare disorder affects humans and other vertebrates.

BSE-Bovine Spongiform Encephalopthy (also known as Mad cow disease) is a transmissible,neurodegenerative, fatal brain disease of cattle.The disease has a long incubation period of four to five years,but ultimately fatal to cattles within weeks to months of its onset.BSE affects the brain and spinal cord of the cattle.The lesions are characterised by a sponge like  appearence which is vissible under ordinary microscope.

The nature of the TSE/BSE agent is still a matter of debate. According to the prion theory, the agent is composed largely, if not entirely, of a self-replicating protein, referred to as a prion. Another theory argues that the agent is virus-like and possesses nucleic acids which carry genetic information. Strong evidence collected over the past decade supports the prion theory, but the ability of the TSE/BSE agent to form multiple strains is more easily explained by a virus-like agent.

TSE/BSE's are caused by an abnormal verson of a protein called Prion.Prion protein occur in two forms. 
1.Normal Form:-A harmless protein found in the body cells in unfolded structure,which doesnot cause TSE/BSE.
2.Abnormal(infectious) Form:-This protein appears in the body cells in a folded form,which  cause TSE/BSE.
                                                      
The harmless and infectious forms of prion proteins are nearly identical,but infectious forms have different shape (due to folding) when compared with normal protein and is highly stable, resisting freezing, drying and heating at normal cooking temperatures.

Known Spongiform Encephalopathies (Non Human animals)

1. Scrapie is a fatal, degenerative disease that affects the nervous  system of sheep and goats . It is one of several TSEs, which are related to Bovine Spongiform Encephalopthy  and chronic wasting
disease of deer. Like other spongiform encephalopathies, scrapie is caused by a prion proteins.

2.Transmissible mink encephalopathy (TME) is rare sporadic disease that affects the central nervous system of ranch-raised mink and is believed to be caused by prion proteins. This disease is only known to affect adult mink.

3.Chronic wasting disease (CWD) is a TSE of muledeer,whitetailed deer,elk (wapiti), and moose.

4.Bovine spongiform encephalopathy (BSE),  is a transmissible,neurodegenerative, fatal brain disease of cattle.

5.Feline spongiform encephalopathy is a disease that affects the brains and livers of felines.


Human TSEs

TSE diseases of humans include Creutzfeldt–Jakob disease,new variant Creutzfeldt–Jakob disease (nvCJD, a human disorder related to madcow disease),Kuru,Gerstmann–Sträussler–Scheinker syndrome (GSS) & Fatal familial insomnia (FFI).

Human TSE's can occur in three ways
1.Sporadically
2.As heriditary diseases
3.Through transmission from infected individuals.

TSE's cannot be transmitted through the air or through touching or most other forms of casual contact.However they may transmitted through contact with infectious tssue,body fluids or contaminated medical instruments.Normal sterilization procedure such as boiling or irradiating materials do not prevent transmission of TSE's.

Symptoms of TSE'svaries but commonly includes personality changes,psychiatric problems such as depression,lack of coordination etc.Patients may also experience involentry jerking movements,unusual sensations,insomnia and memmory problems.In latter stage of the disease,patients have severe mental impairment and lose the ability to move or speak.

At present, there is no proven specific or effective treatment available for any form of TSE.
There is increasing concern about the troubling possibility that blood or blood products, vaccines and other pharmaceutical products could spread the agent of variant CJD (vCJD) worldwide, especially in countries where BSE has not yet been reported. Bovine derived materials involved in the production of vaccines and other pharmaceutical products could represent a way of potential transmission of the disease. Moreover, the possibility that human blood and plasma could be a vehicle for the transmission and spread of the disease have led to a number of donor deferral policies aimed at minimizing the risk of accepting a blood donor who might be incubating the human form of BSE. In addition, blood fractionated products such as albumin are used as stabilizers in the production of vaccines and recombinant pharmaceutical products. There is, therefore, a need to ensure that regulatory authorities with limited resources can have reliable information when making their risk assessment and evaluation of product safety to prevent the transmission of TSE to human via biological and pharmaceutical products.
Regulations to minimize the TSE/BSE risks.Since the use of animal-derived materials is unavoidable for the production of some medicinal products and that complete elimination of risk at source is rarely possible, the measures taken to manage the risk of transmitting animal TSEs via medicinal products represent risk minimisation rather than risk elimination.
TSE-relevant animal speciesCattle, sheep, goats and animals that are naturally susceptible to infection with transmissible spongiform encephalopathy agents or susceptible to infection through the oral route other than humans and non-human primates are defined as ‘TSE-relevant animal species’

When manufacturers have a choice the use of materials from ‘non TSE-relevant animal species’ or non-animal origin is preferred. The rationale for using materials derived from ‘TSE- relevant animal species’ instead of materials from ‘non-TSE- relevant species’ or of non-animal origin should be given. If materials from ‘TSE-relevant animal species’ have to be used, consideration should be given to all the necessary measures to minimise the risk of transmission of TSE.
Minimising the risks of transmission of TSE is based upon three complementary parameters:

— the source animals and their geographical origin,

— nature of animal material used in manufacture and any procedures in place to avoid

     cross-contamination with higher risk materials.

— production process(es) including the quality assurance system in place to ensure

     product consistency and traceability.
The Source Animals Animals fit for human consumption following Ante-and post mortem inspection shall only be used for the manufacture of medicinal products.In case of live animals, it should be found healthy after clinical examinations.

Geographical OriginThe geographical origin status is established by two agencies. Firstly, the Organization for Internationale des Epizooties (OIE) and secondly, the European Commission Scientific Steering Committee (SCC). According to SCC, the countries have been classified according to the Geographical BSE Risk (GBR). According to SSC GBR classification, the countries are categorized in four levels as below

Higher level is defined as equal to or more than 100 cases per million adult cattle per year. New Zealand and Australia are the preferred sources of animal origin products of small ruminants.

GBR Level	Presence of one or more cattle clinically or pre-clinically infected with BSE in a geographicalregion/country
Level -I	Highly unlikely
Level -II	Unlikely but not excluded
Level -III	Likely but not confirmed or confirmed at lower level
Level -IV	Confirmed at higher level

Higher level is defined as equal to or more than 100 cases per million adult cattle per year. New Zealand and Australia are the preferred sources of animal origin products of small ruminants.

BSE negligible risk bovine Herds

GBR level –I countries have been considered as BSE negligible risk bovine herds as there is a highly unlikely status.

vAnimal Parts, Body Fluids and Secretions as Starting Material

In a TSE infected animal, different organs and secretions have different levels of infectivity. Based on the infectivity, the tissue have been classified as below.

Category A (Shall not be used,unless justified)	High Infectivity Tissues	(Central Nervous System) CNS and tissues anatomically associated with CNS
Category B (Forexample, blood)	Lower Infectivity Tissues	Peripheral tissues tested positive for infectivity and/or in at least one form of TSE
Category C (Thoughthe risk is less, it shall be used only upon adequaterisk assessment)	Tissues with no detectable infectivity	Tissues tested for infectivity and found no infection

GBR classification with respect to the risk of TSE/BSE has been conducted by Scientific Steering Committee (SSC) and European Food Safety Authority (EFSA). The outcome of assessment and year of publication reveals the GBR assessment as below11.

The SSC has classified the GBR level –I countries as follows: Argentina-2003| Australia-2000| Botswana-2001| Brazil-2003Chile-2003| Costa Rica-2003| El Salvador-2001| Iceland-2002Namibia-2001| NewCaledonia-2003| New Zealand-2002| Nicaragua-2001Norway-2000| Panama-2001| Paraguay-2003| Singapore-2003Swaziland-2001| Uruguay-2003| Vanuatu-2002.

However, The EFSA at a later stage has classified some of the above countries in GBR level-II & III.Botswana-2005 –GBR-II| Brazil-2005 –GBR-II | Chile-2005 –GBR-III Costa Rica-2005 –GBR-II | El Salvador-2005 –GBR-II| Namibia-2005 –GBR-IINicaragua-2005 –GBR-II| Norway-2004 –GBR-II| Swaziland-2005 –GBR-II.

The SSC has classified the GBR level –II countries as follows: Canada-2000| Columbia -2001| India-2001| Kenya-2001Mauritius -2001| Nigeria-2001| Pakistan-2001| Sweden-2000USA-2000However, The EFSA at a later stage has classified some of the above countries in GBR level-III like Canada and USA in 2004.

The SSC has classified the GBR level –III countries as follows: Andorra-2002| Albania-2001| Austria-2003| Belarus-2003Belgium-2000| Bulgaria-2002| Crotia-2002| Cyprus-2003Denmark-2000| Estonia-2001| Finland-2002 | Czech Republic-2001France-2000| Germany-2000| Greece-2002| Republic of Macedonia-2003Hungary-2001| Ireland-2000| Israel-2002| Italy-2000Latvia-2002| Lithunia-2003| Luxembourg-2000| Malta-2002Netherlands-2000| Poland-2001| Romania-2001| San Marino-2002Slovenia-2002| Spain-2000|Switerland-2001 | Slovak Republic-2001Turkey-2002The EFSA has not classified any countries from GBR level-III to any other level.

The SSC has classified the GBR level –IV countries in the year 2000 as follows: United Kingdom and Portugal.

Note:For current updates, reference shall be made from the website of EFSA.

Cross ContaminationThere is potential risk of cross contamination of the different types of tissues while the collection of the desired animal parts. The risk of cross contamination is depend upon on the stunning or slaughtering methods employed.

There is a high risk if penetrative brain stunning method is employed or if the brain or spinal cord is sawed. The risk can be minimized in such a way that there is minimal damage to tissue and cellular components.

Collection of parts such as Skull shall be considered for risk assessment as it is high-infectivity tissue.

For certain cases, the separation/removal of higher infectivity tissues from lower infectivity tissues is very difficult and appropriate procedures must be in place for the collection of such body parts/fluids. The role of stunning/slaughtering methods plays an important role in cross contamination and by applying adequate procedures the risk can be minimized.

The risk of cross contamination, procedures applied for stunning/slaughtering, procedures for collection of parts/fluids, procedures for the separation and removal parts, and measures taken to avoid cross contamination must be detailed in the Marketing Authorization Application (MAA) by the Applicant.

Age of Animals The age of animals plays a important role in determining the TSE/BSE status as the incubation period is too long. It is considered sensible to source desired product/material from young animals.

Manufacturing ProcessMeasures taken into account to minimize the risk with respect to Sourcing of raw/starting material and the manufacturing process plays a inevitable role in controlling TSE/BSE in pharmaceuticals.

A quality assurance system such as ISO certification, Hazard Analysis Critical Control Point (HACCP) or GMP must be in place for the manufacturing of animal derived products.

The quality system must encompass the basic requirements like Batch Manufacturing system, Cleaning between batches using 20000 ppm chlorine for 1 hour, Self audit, in-process controls , Isolation and Separation by physical means via filtration, steps/stages of manufacturing, dedicated use of equipments, and traceability systems of each batch inputs. The quality system shall also be described in the MAA.

Removal/inactivation studies shall be carried out based on the available identification techniques, spiking studies and possible investigations of removal and inactivation techniques .

If no animal origin material is used, there is no risk of TSE/BSE. However, a declaration for all raw materials/reagents/Packing materials regarding TSE/BSE-risk-free-status is required.

If any animal origin material and/or any material comes in contact with animal origin material is used, risk evaluations of TSE/BSE must be done according to the guidance.

In case of mandatory requirement of animal origin material, low infectivity material is preferred.

In case of mandatory requirement of animal origin material, it can be produced from GBR Level-I countries.

In case of high infectivity material, the need must be justified.

If the product is at risk, an expert certificate is required indicating the level of risk and infectivity.

For biotechnological products like serums, vaccines and blood products needs a complete verification of TSE/BSE status.

Products like enzymes, collagens and gelatin, amino acids the specific conditions as provided in EP general chapter 5.2.8 shall be met.


In case of use of animal origin material, the following shall be verified in general

Type of tissue/body part/fluid used

Type of animal from which the material is required (Ruminant/non-ruminant/bovine/ Caprine /Ovine/Porcine)

Age of animals/health status from which the material is required

Geographical origin of the animal (Country/Continent)

A detailed risk assessment and expert certification

Type of stunning/slaughtering method employed

Type of certification like ISO, HACCP or GMP of the manufacturer of animal product manufacturer

Traceability of animal slaughtering source

Methods of segregation of tissues during slaughtering

Potential of cross contamination during slaughtering/Packing/handling

Name, complete address of the supplier

Prior reduction claims from the manufacturer of animal derived products

CEP certification of the pharmaceutical product

Information regarding the Facility of manufacturing animal derived material.

Information regarding Products derived from elk, deer.