risk analysis for veterinary biologics: case studies · risk analysis for veterinary biologics:...

Risk Analysis for

Veterinary Biologics:

Case Studies

Richard E. HILL, Jr., Patricia FOLEY

Center for Veterinary Biologics Veterinary ServicesAnimal and Plant Health Inspection ServiceUnited States Department of AgricultureAmes, Iowa USA

Center for

Veterinary Biologics

United States Department of Agriculture

Animal and Plant Health Inspection Service

Topics

► Risk Analysis for Biotechnology-

derived Biologics (brief summary)

► Case Studies

► Vectored vaccines (review of risk

decisions and mitigations)

► Transgenic Plant-derived Vaccines

(additional considerations and example)

► Emerging Issues and Unique

Biologics

Risk Review of

Biotech-derived Applications

► Data: Summary Information Format (SIF)

– The biologics firm provides the requested information

using the pertinent SIF, reviewed by USDA

► Risk Assessment (RA) outline

– Completed by the firm, evaluated by USDA

► Risk analysis by USDA of proposed field safety trials

– Environmental assessment (EA) of any potential effects

• On animal safety, public health, or the environment

Biotech Risk Assessment

Objective of Studies: ID Hazards

► Examine genotypic and phenotypic stability in target

host animals (reversion to virulence?)

► Evaluate changes in tissue tropism

► Assess shed/spread capabilities

► Assess host range specificity

► Consider recombination potential and consequences

► Identify effect of overdosing

► Assess survivability in environment

► Expected risk: Risk Rating = [(L) x (D)] x [(C) x (D)]

Formal Risk Review of

Biotechnology-Derived Products

► USDA conducts Master Seed & prelicense serial testing

► The firm provides to USDA

– Confidential business information-deleted SIF/RA

► For live vaccines: Federal Register Notice of pending

trials

– CBI-deleted SIF/RA & EA available to the public

– Public comment period

– Finding of No Significant Impact (FONSI)

– Approval of field trials if no issues arise

► Licensure

– If the field trials showed the product to be safe and all

other requirements are met

Request to Ship + Test

an Experimental Biologic – 9 CFR 103.3

Analysis of pre-license data & information

Hazard Identification &

Release Assessment

Risk Characterization

Low:

Acceptable Risk

Approve Request

Medium:

Unacceptable Risk

Satisfactory

Mitigation

Yes: Approve Request No: Deny Request

High:

Unacceptable Risk

Deny Request

Environmental Considerations

► Deliberate release of any organism containing

recombinant DNA into the environment is subject to

review and approval by appropriate Federal

agencies.

► Under normal husbandry and laboratory practices,

injected veterinary biologicals are not considered to

be released into the environment if testing shows the

agents are not shed.

Overview

► Each biotech product is evaluated individually

to determine the appropriate requirements to

establish purity, safety, potency, and efficacy.

► Replication proficient products must undergo

an environmental risk assessment.

► Killed or inactivated (non-replication

competent) biotechnology products must

undergo an abbreviated risk assessment.

Case Studies

► Vaccinia-vectored oral baited rabies vaccine

(V-RG) for wildlife

► Canarypox-vectored vaccines

► Transgenic plant-derived vaccines

► Risks

– < 1960, mostly domestic animals

– Now: > 90% of animal cases in

wildlife (carnivores, bats)

– Livestock: most often cattle & horses

► Costs

– > $300 million/year in US for oral rabies vaccine (ORV)

– FY2007: 11,361,002 ORV baits in 17 states

► Need new ORVs, baits & biomarkers

– Current ORV effective in raccoon, coyote, gray fox

– Need vaccines for use in skunk, bat, mongoose

Rabies

U. S. Risks and Costs

Rabies

Domestic Animals

Rabies

Wild Animals

Licensed Global Vaccines

►ORV - attenuated strains (various SAD vaccine

viruses, ERA G 333) – red foxes, raccoons

► ORV - freeze-dried or encapsulated SAG2 – dogs,

red foxes, raccoons

► Cell culture or nerve-tissue KV for use in dogs,

cats, ferrets, horses, cattle, or sheep

► Live poxvirus vectored vaccines, per WHO, 2004:

● > 75 million doses of V-RG – red foxes

(Belgium, France, Israel, Luxemburg, Ukraine);

raccoons (Republic of Korea); coyotes,

raccoons, grey foxes (Canada, US), domestic

dogs (Sri Lanka)

Rabies Virus

V-RG Oral Rabies Vaccine

Case Study

►1983: Vaccinia-vectored vaccine developed containing

Rabies glycoprotein G – unique, baited, oral use in wildlife

►Extensive studies in containment, then in the field (Belgium,

France): contact with baits in a wide variety of species

►Safe in rabbits, various spp. mice + voles, woodchucks,

squirrels, badgers, fox, raccoon, skunk, coyote, wild boar,

gulls, hawks, owls, buzzards, kestrels, crows, magpies, jays

►Risk review for environmental release in the US:

NEPA: recombinant, air- + land-based bait drops

Public health: zoonotic concerns

Review by subject matter experts, public meetings


Raccoons

►1st North American test: August 20,1990, the Wistar Institute

initiated a field trial on Parramore Island, Virginia

►1991: field trials in Pennsylvania

►1992-94: field trials in New Jersey

►April 20, 1995, Conditional license for use in raccoons

►Today: 16 states use V-RG to control raccoon rabies,

1 state uses for gray fox + coyote rabies

►Example: Ohio with 59 positive raccoons in 1997, but no

positive cases in 2000, only 1 in 2001


Coyote and Fox

►1994 Efficacy studies in coyotes & foxes

prior to field trials with experimental vaccine

►1995 Experimental field use in Texas

►Annual use of experimental vaccine in Texas, with

manufacturer submitting reports of the testing results

►May 16, 2002, USDA accepted data supporting a label

claim for use in coyotes

►Currently, fully licensed for use in raccoons, coyotes;

conditionally licensed for use in gray foxes.





Release Assessment


Low:

Acceptable Risk

Approve Request

Medium:

Unacceptable Risk

Satisfactory

Mitigation


High:

Unacceptable Risk

Deny Request

Rabies

Wild Animals

Canarypox Vectored Vaccines

Case Study► The backbone strain “ALVAC” is derived from an

attenuated vaccine strain KANAPOX®

► Tested in humans and animals: NIH Risk Group 1 (lowest)

► Host range is restricted: no replication in mammalian cells,

but protein is expressed for an immune response

► Many back passage and shed-spread studies, tests in target

and non-target species, incl. 4 spp. of mosquitoes

► Vaccines are for canine distemper (1st), feline rabies, several

strains of equine flu, West Nile virus, feline leukemia

► Field trials in at least 3 different geographical areas for each

of these prelicense vaccines





Release Assessment


Low:

Acceptable Risk

Approve Request

Medium:

Unacceptable Risk

Satisfactory

Mitigation


High:

Unacceptable Risk

Deny Request

Category I: Non-replicating

Recombinant Antigen(s)

► Subunit or Killed Vaccines – examples:

► Feline Leukemia, Porcine Circovirus

► Diagnostic Kits – examples:

► Antibody Test Kits for EIA, IBD, AI, PRRS Viruses

► Antibody Test Kits for Anaplasma, Babesia Equi,

B. Caballi

DNA Vaccines - examples:

► West Nile virus, Canine Melanoma

Category II: Live Gene-Deleted

► Salmonella Typhimurium Vaccine

► Poultry

► Escherichia Coli Vaccine

► Poultry

► Salmonella Dublin Vaccine

► Bovines

► Pseudorabies Vaccine

► Swine

Category III Licensed Live

Vectored Vaccines

► ~15 live vectored vaccines: some are made by several

companies +/or are in combination vaccines

► Antigens in fowl pox vector: from avian influenza H5,

Newcastle disease virus, infectious laryngotracheitis virus

► Antigens in turkey herpesvirus vector: from Marek‟s

disease virus, Newcastle disease virus, infectious bursal

disease, infectious laryngotracheitis virus

► Rabies glycoprotein in vaccinia virus vector

► Marek‟s disease virus: herpes-chimera

► Antigens in canarypox vector: from canine distemper,

rabies, equine influenza, West Nile, feline leukemia virus

Transgenic Plants

as Bioreactors

► Potential for high levels of accumulated

recombinant proteins: faster, less cost, easier

► Expression by transient vectors, or stable transgenes

(through nuclear or chloroplast transformation)

► Glycosylation differences apparently not problematic;

post-translational modifications occur

► Compartmentalization within the cell (e.g. chloroplast)

► Natural storage stability in certain organs (e.g. seeds)

► No contamination from animal byproducts

► Ease of delivery: possibly oral, with no „cold chain‟

requirement for refrigeration

Types of Plant-Based Biologics

► Vaccines

– Feed-based for oral mucosal immunization

• Whole plant or partial plant

– Purified protein

• Parenteral subunit or feed additive

► Plantibodies

► Diagnostic kit components

– Antigens, plantibodies

Safety Considerations

►Environmental effects

– Non-target animals

– Pollen drift: spatial & temporal

• Food crops

• Wild/weedy relatives

– Confinement, persistence, dormancy

►Accidental release to food/feed facility

– Viable/nonviable material

– Health risk: toxin, allergen,

immunotolerance?

– Loss of public confidence in segregation

Guidance Documents

► USDA/FDA, 9/12/02 – Guidance for Industry

– Drugs, biologics, and medical devices derived from

bioengineered plants for use in humans and animals

► USDA/APHIS, 7/9/08 – Guidance

▬ APHIS Permits for Field Testing or Movement of

Organisms Intended for Pharmaceutical or Industrial

Use

► USDA/APHIS, 10/9/08 – Proposed Rule

▬ Importation, Interstate Movement, and Release Into the

Environment of Certain Genetically Engineered

Organisms

Requirements for Oral Vaccines

► Outline must state pesticide, herbicide use

► Serial: mixed as a batch or representative sampling to

demonstrate homogeneity

► Purity: within accepted levels for mycotoxins, pesticides,

herbicides, soil-borne contaminants, naturally occurring

plant toxins, etc.

► Target Animal Safety: overdose/tolerance study but not

reversion-to-virulence; reproductive safety; response in

young/old

► Environmental safety: use, manufacture, disposal

► Potency & stability: identify & measure the protective Ag

or Ab in bulk or finished product

Transgenic Plant Cell Line

Producing a Subunit Vaccine

► 1st plant cell-derived vaccine: Newcastle Disease Vaccine,

Subunit, licensed in 2006, modified tobacco cell line

► Testing=9CFR, Parts 101-124 (conventional regs), plus:

► Genetic and phenotypic ID of the Master Cell Line

► Transformation event and passage history

► Testing for host plant cell-specific pathogens and unwanted

secondary metabolites

► Genetic, phenotypic stability at X and X + _

(highest pass used in production)

– Methods other than karyology

Transgenic Plant-Derived

Proteins for Animal Vaccines*

► Rabbit hemorrhagic disease virus

– VP60 in potato (injection)

► Foot-and-mouth disease virus

– VP1 in Arabidopsis (injection)

– VP1 in alfalfa (injection, oral)

► Transmissible gastroenteritis virus

– S protein in Arabidopsis (injection)

– S protein in tobacco (injection)

– S protein in maize (oral)

*Daniell et al., Trends in Plant Science 6:219-226, 2001

Additional Transgenic

Plant-Derived Animal Vaccines

► Infectious bursal disease virus VP2: in Arabidopsis (oral)

► Enterotoxigenic E. coli binding inhibitor: from tobacco (oral)

► Canine parvovirus VP2: from recombinant plant virus,

also tobacco chloroplasts (injection)

► Classical swine fever virus E2: tobacco chloroplasts (injctn.)

► Foot and mouth disease virus VP1 epitope: in Arabidopsis,

alfalfa, and potato (injection, oral)

► Bovine rotavirus epitope eBRV4: in alfalfa (injection, oral)

► Bovine viral diarrhea virus E2: in alfalfa (injection, oral)

► Newcastle disease virus: from tobacco plants

Unique Vaccines/Emerging Issues

Nanovaccines – the (distant) future???

Unique Vaccines/Emerging Issues

► Foreign animal diseases: [example: Foot-and-Mouth

Disease Vaccine, Live Adenovirus Vector (pending field

trials, testing on US mainland)]

► Compendium of Veterinary Vaccines for Transboundary

Diseases: www.cfsph.iastate.edu/Vaccines/index.php

► Innovations: [example: modified live vaccines for use in

pregnant animals (e.g. Bovine virus diarrhea {BVD} virus,

special testing requirements)]

► Public perception of risk (Biotechnology)

► Domestic/wildlife interface

► “One Health” approach (zoonotic agents)

► Regulatory flexibility and product innovation

Questions or comments?