Viruses, Serums, Toxins, and Analogous Products; Marek's Disease Vaccines

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DEPARTMENT OF AGRICULTURE

Animal and Plant Health Inspection Service

9 CFR Parts 112 and 113

[Docket No. 94-046-2]

Viruses, Serums, Toxins, and Analogous Products; Marek's Disease

Vaccines

AGENCY: Animal and Plant Health Inspection Service, USDA.

ACTION: Final rule.

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SUMMARY: We are amending the standard requirements for Marek's disease

vaccines by including vaccines prepared from any of the three Marek's

disease virus serotypes, and by defining the identity, safety, and

efficacy requirements for vaccines prepared from each serotype or

combinations of serotypes. We are also amending the requirements for

labeling Marek's disease vaccines. These amendments are necessary based

on the evolution of virus serotypes in the field, advances in the

development of vaccines that are currently prepared to prevent the

disease, and advances in the methods for evaluating such vaccines. The

effect of this rule will be to save license applicants time by

clarifying and codifying the guidelines developed for licensing these

products over the past several years.

EFFECTIVE DATE: July 31, 1996.

FOR FURTHER INFORMATION CONTACT: Dr. David Espeseth, Deputy Director,

Veterinary Biologics, BBEP, APHIS, 4700 River Road Unit 148, Riverdale,

MD, 20737-1237, (301) 734-8245.

SUPPLEMENTARY INFORMATION:

Background

Veterinary biologics are regulated under the Virus-Serum-Toxin Act

of 1913, as amended by the Food Security Act of 1985 (21 U.S.C. 151-

159, hereinafter referred to as the Act). In accordance with the Act,

the Animal and Plant Health Inspection Service (APHIS) promulgates

standard requirements that establish the purity, safety, potency, and

efficacy requirements for these products.

The current standard requirements in Sec. 113.330 (hereinafter

referred to as the regulations) for licensing Marek's disease vaccines

were promulgated at a time when only Serotype 3 Marek's disease

vaccines were prepared. Also, the standard requirements did not include

the evaluation of vaccine efficacy. Since that time, vaccines for

Serotypes 1 and 2 have been developed, very virulent forms of the field

virus have emerged, and other advances in our understanding of this

virus have occurred. In response to these changes, APHIS has developed

guidelines over the past several years for licensing these products.

On May 9, 1995, we published in the Federal Register (60 FR 24584-

24587, Docket No. 94-046-1) a proposal to amend the standard

requirement for Marek's disease vaccines to include Serotypes 1 and 2,

and to codify appropriate efficacy standards and guidelines which

license applicants have utilized.

We solicited comments concerning our proposal for 60 days ending

July 10, 1995. We received two comments by that date. They were from an

association of poultry producers and a poultry producer. Both

commenters agreed with the need for the establishment of standard

requirements for vaccines prepared from any of the three Marek's

disease virus serotypes. Both commenters were in favor of the rule as

proposed.

In preparing the final rule, APHIS observed that it is necessary to

clarify the appropriate use of the group 4 controls in Sec. 113.330,

paragraphs (c)(1)(4) and (c)(4), to assess the severity of serotype 1

virus challenge in an immunogenicity test. The proposed rule specified

that ``at least'' (i.e., ``greater than or equal to'') 20 percent of

the birds in group 4 must have lesions for a valid test after serotype

1 virus challenge in birds vaccinated with a serotype 3 vaccine (see

Sec. 113.330, paragraph (c)(4)). For a satisfactory serotype 3 vaccine

immunogenicity test, the proposed rule specified that 80 percent of

vaccinated birds must be free of lesions (see Sec. 113.330, paragraph

(c)(5)). Stated another way, 20 percent of the vaccinated birds may

have lesions for a satisfactory serotype 3 vaccine immunogenicity test.

When the severity of virulence of the challenge virus for a

serotype 1 or 2 vaccine in group 4 controls is equal to that for

serotype 3 vaccine, the result would be inconsistent with a claim to

aid in the prevention of disease against a very virulent serotype 1

virus (see Sec. 113.330(c)(5)). If the birds in group 4 show 20 percent

or fewer lesions, the challenge virus is deemed not sufficiently

virulent and the test is declared invalid.

Therefore, proposed Sec. 113.330(c)(4) is amended to read ``greater

than'' (in place of ``at least'') 20 percent of vaccinated birds in

group 4 controls must have lesions for a valid immunogenicity test

after challenge with more virulent serotype 1 virus. The amendment to

proposed Sec. 113.330(c)(4) should not hold the vaccine producer to a

higher standard than was originally proposed. This is because the

proposed rule specified that the group 4 control would not apply to the

case of a serotype 3 vaccine challenge virus that requires that 20 per

cent of the vaccinated birds have lesions (see Sec. 113.330(c)(1)(iv)).

Thus, the amendment to Sec. 113.330(c)(4) is consistent with APHIS'

original intent that immunogenicity tests for serotype 1 and 2 vaccines

be based on challenge viruses more virulent than that for serotype 3

vaccines.

Therefore, based on the rationale set forth in the proposed rule

and this document, we are adopting the provisions of the proposal as a

final rule with the change discussed in this document.

Executive Order 12866 and Regulatory Flexibility Act

This rule has been reviewed under Executive Order 12866. The rule

has been determined to be not significant for purposes of Executive

Order 12866 and, therefore, has not been reviewed by the Office of

Management and Budget.

The amendments to the standard requirements for Marek's disease

vaccines codify guidelines developed for licensing these products over

the past several years. These amendments affect all (currently a total

of eight) manufacturers of Marek's disease vaccines, some of which may

be small businesses. By clarifying licensing requirements for Marek's

disease vaccines, the rule will save time during the application

process and will not cause an adverse economic impact on industry.

Under these circumstances, the Administrator of the Animal and

Plant Health Inspection Service has determined that this action will

not have a significant economic impact on a substantial number of small

entities.

Executive Order 12372

This program/activity is listed in the Catalog of Federal Domestic

Assistance under No. 10.025 and is subject to Executive Order 12372,

which requires intergovernmental consultation with State and local

officials. (See 7 CFR part 3015, subpart V.)

Executive Order 12778

This final rule has been reviewed under Executive Order 12778,

Civil Justice Reform. It is not intended to have retroactive effect.

This rule would not preempt any State or local laws, regulations, or

policies, unless they present an irreconcilable conflict with this

rule. There are no administrative procedures that must be exhausted

prior

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to a judicial challenge to the provisions of this rule.

Paperwork Reduction Act

This rule contains no new information collection or recordkeeping

requirements under the Paperwork Reduction Act of 1995 (44 U.S.C. 3501

et seq.).

List of Subjects

9 CFR Part 112

Animal biologics, Exports, Imports, Labeling, Packaging and

containers, Reporting and recordkeeping requirements.

9 CFR Part 113

Animal biologics, Exports, Imports, Reporting and recordkeeping

requirements.

Accordingly, 9 CFR parts 112 and 113 are amended as follows:

PART 112--PACKAGING AND LABELING

1. The authority citation for part 112 continues to read as

follows:

Authority: 21 U.S.C. 151-159; 7 CFR 2.22, 2.80, and 371.2(d).

2. Section 112.7 is amended by adding paragraph (m) to read as

follows:

Sec. 112.7 Special additional requirements.

* * * * *

(m) In the case of biological products containing Marek's disease

virus, all labels shall specify the Marek's disease virus serotype(s)

used in the product.

PART 113--STANDARD REQUIREMENTS

3. The authority citation for part 113 continues to read as

follows:

Authority: 21 U.S.C. 151-159; 7 CFR 2.22, 2.80, and 371.2(d).

4. Section 113.330 is revised to read as follows:

Sec. 113.330 Marek's Disease Vaccines.

Marek's disease vaccine shall be prepared from virus-bearing tissue

culture cells. Only Master Seed Virus which has been established as

pure, safe, and immunogenic shall be used for preparing the production

seed virus for vaccine production.

(a) The Master Seed Virus shall meet the applicable requirements

prescribed in Sec. 113.300, and the requirements prescribed in this

section. The identity test required in Sec. 113.300(c) shall be

conducted in a serotype-specific manner by a method acceptable to

APHIS. Each lot of Master Seed Virus shall also be tested for pathogens

by the chicken embryo inoculation test prescribed in Sec. 113.37,

except that, if the test is inconclusive because of a vaccine virus

override, the chicken inoculation test prescribed in Sec. 113.36 may be

conducted and the virus judged accordingly.

(b) Safety test. The Master Seed Virus shall be nonpathogenic for

chickens as determined by the following procedure:

(1) Specific pathogen free chickens or embryos, negative for

Marek's disease virus antibodies, and from the same source, shall be

isolated into the following groups:

(i) Group 1. At least 50 test subjects shall be inoculated with 10

times as much viable virus as will be contained in one dose of vaccine,

by the route recommended for vaccination.

(ii) Group 2. At least 50 test subjects shall be injected with a

very virulent Marek's disease virus provided or approved by APHIS, at a

dosage level that will cause gross lesions of Marek's disease in at

least 80 per cent of the chickens within 50 days.

(iii) Group 3. Fifty uninoculated controls. For in ovo studies,

this group should receive a sham inoculation of diluent.

(iv) Group 4. For studies evaluating Serotype 1 Master Seed

Viruses, a group of 50 uninoculated control chickens shall be housed in

contact with the group 1 vaccinated chickens.

(2) At least 40 chickens in each group shall survive to 5 days of

age. All chickens that die shall be necropsied and examined for lesions

of Marek's disease and cause of death. The test shall be judged

according to the following criteria:

(i) At 50 days of age, the remaining chickens in group 2 shall be

killed and examined for gross lesions of Marek's disease. If at least

80 percent of this group do not develop Marek's disease, the test is

inconclusive and may be repeated.

(ii) At 120 days of age, the remaining chickens in groups 1, 3, and

4 shall be weighed, killed, and necropsied. If less than 30 of the

chickens in group 3 survive the 120 day period, or if any of the

chickens in group 3 have gross lesions of Marek's disease at necropsy,

the test is declared inconclusive. If less than 30 chickens in groups 1

and 4 survive the 120 day period; or if any of the chickens in groups 1

and 4 have gross lesions of Marek's disease at necropsy; or if the

average body weight of the chickens in groups 1 or 4 is significantly

(statistically) different from the average in group 3 at the end of the

120 days, the lot of Master Seed Virus is unsatisfactory.

(3) For tests involving in ovo inoculation, hatchability results

shall also be reported for each group.

(c) Immunogenicity. Each lot of Master Seed Virus used for vaccine

production shall be tested for immunogenicity at the highest passage

level allowed for the product, and the virus dose to be used shall be

established as follows:

(1) Specific pathogen free chickens or embryos, negative for

Marek's disease antibodies, and from the same source, shall be isolated

into the following groups:

(i) Group 1. A minimum of 35 test subjects shall be inoculated with

the vaccine, using the recommended route, at 1 day of age for chicks or

18 days of embryonation for embryos. The dose used shall be established

by 5 replicate virus titrations conducted by a cell culture system or

other titration method acceptable to APHIS.

(ii) Group 2. A minimum of 35 nonvaccinated test subjects shall be

held as challenge controls.

(iii) Group 3. A minimum of 25 nonvaccinated test subjects shall be

held as nonchallenge controls.

(iv) Group 4. Except for studies evaluating vaccines which contain

only a Serotype 3 virus as the Marek's disease fraction, a minimum of

35 chicks shall be vaccinated at 1 day of age with a licensed Serotype

3 vaccine, in order to document the severity of the very virulent

challenge.

(2) At least 30 chickens in groups 1, 2, and 4, and at least 20

chickens in group 3, shall survive to 5 days of age. All chickens in

groups 1, 2, and 4 shall be challenged at 5 days of age in the

following manner:

(i) For studies evaluating vaccines which contain only a Serotype 3

virus as the Marek's disease fraction, groups 1 and 2 shall be

inoculated with a standard virulent challenge virus provided or

approved by APHIS.

(ii) For all other Marek's disease vaccines, groups 1, 2, and 4

shall be inoculated with a very virulent challenge virus provided or

approved by APHIS.

(3) All chickens shall be observed until 7 weeks of age,

necropsied, and examined for grossly observable lesions consistent with

Marek's disease. All chickens dying before the end of the 7 week

observation period shall be necropsied and evaluated for gross lesions

of Marek's disease. Any chickens not so examined shall be scored as

positive for Marek's disease.

(4) For a valid test, at least 80 percent of the chickens in group

2 must develop grossly observable lesions, none of the chickens in

group 3 shall develop

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grossly observable lesions, and (when included) greater than 20 percent

of the chickens in group 4 must develop grossly observable lesions.

(5) For a valid test to be considered satisfactory, at least 80

percent of the chickens in group 1 must remain free of grossly

observable lesions. The appropriate product claim resulting from a

satisfactory test would be to aid in the prevention of Marek's disease,

for vaccines containing only a Serotype 3 virus as the Marek's disease

fraction, or to aid in the prevention of very virulent Marek's disease,

for all other vaccines.

(d) Test requirements for release. Each serial and subserial shall

meet the applicable requirements prescribed in Sec. 113.300. The

identity test required in Sec. 113.300(c) shall be conducted in a

serotype-specific manner by a method acceptable to APHIS. Final

container samples of completed product shall also meet the requirements

in paragraphs (d) (1), (2), and (3) of this section. Any serial or

subserial found unsatisfactory by a prescribed test shall not be

released.

(1) Purity test. The chicken embryo inoculation test prescribed in

Sec. 113.37 shall be conducted, except that, if the test is

inconclusive because of a vaccine virus override, the chicken

inoculation test prescribed in Sec. 113.36 may be conducted and the

virus judged accordingly.

(2) Safety test. At least 25 one-day-old, specific pathogen free

chickens shall be injected, by the subcutaneous route, with the

equivalent of 10 chicken doses of virus (vaccine concentrated 10X). The

chickens shall be observed each day for 21 days. Chickens dying during

the period shall be examined, cause of death determined, and the

results recorded.

(i) If at least 20 chickens do not survive the observation period,

the test is inconclusive.

(ii) If lesions of any disease or cause of death are directly

attributable to the vaccine, the serial is unsatisfactory.

(iii) If less than 20 chicks survive the observation period and

there are no deaths or lesions attributable to the vaccine, the test

may be repeated one time, Provided, that if the test is not repeated,

the serial shall be declared unsatisfactory.

(3) Potency test. The samples shall be titrated using a cell

culture system or other titration method acceptable to APHIS. For

vaccines composed of more than one Marek's disease virus serotype, each

fraction shall be titrated in a serotype-specific manner.

(i) Samples of desiccated vaccine shall be incubated at 37 deg.C

for 3 days before preparation for use in the potency test. Samples of

desiccated or frozen vaccine shall be reconstituted in diluent

according to the label recommendations, and held in an ice bath at

0 deg.C to 4 deg.C for 2 hours prior to use in the potency test.

(ii) For a serial or subserial to be eligible for release, each

serotype contained in the vaccine shall have a virus titer per dose

which is at least 3 times greater than the number of plaque forming

units (pfu) used in the immunogenicity test prescribed in paragraph (c)

of this section, but not less than 1000 pfu per dose.

(iii) When tested (without the pretest incubation of desiccated

products) at any time within the expiration period, each serotype

contained in the vaccine shall have a virus titer per dose which is at

least 2 times the number of pfu used in the immunogenicity test, but

not less than 750 pfu per dose.

Done in Washington, DC, this 25th day of June 1996.

Donald W. Luchsinger,

Acting Administrator, Animal and Plant Health Inspection Service.

[FR Doc. 96-16710 Filed 6-28-96; 8:45 am]

BILLING CODE 3410-34-P