[Federal Register Volume 61, Number 127 (Monday, July 1, 1996)]
[Rules and Regulations]
[Pages 33839-33842]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-16710]


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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