[Federal Register Volume 62, Number 110 (Monday, June 9, 1997)]
[Rules and Regulations]
[Pages 31329-31331]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-14996]


-----------------------------------------------------------------------

DEPARTMENT OF AGRICULTURE

Animal and Plant Health Inspection Service

9 CFR Part 113

[Docket No. 92-090-2]


Viruses, Serums, Toxins, and Analogous Products; Revision of 
Standard Requirements for Clostridium Perfringens Types C and D Toxoids 
and Bacterin-Toxoids

AGENCY: Animal and Plant Health Inspection Service, USDA.

ACTION: Final rule.

-----------------------------------------------------------------------

SUMMARY: We are amending the regulations pertaining to the Standard 
Requirements for Clostridium Perfringens Type C and Clostridium 
Perfringens Type D toxoids and bacterin-toxoids. The amendments will 
reduce the minimum number of rabbits required in order to pool their 
serum for testing. This amendment will also clarify the method of 
determining the test vaccine dose in rabbits based on the recommended 
vaccine dosage in cattle and other host animal species.
    These amended regulations will not change the accuracy of the 
assays and, under certain circumstances, will reduce the number of 
required tests as well as the number of mice needed for testing. The 
amendment is necessary to make the potency assays conform more closely 
to the revised standard requirements for Clostridium Novyi and 
Clostridium Sordellii Bacterin-Toxoids and more economical to run when 
combination products containing these fractions are tested.

EFFECTIVE DATE: July 9, 1997.

FOR FURTHER INFORMATION CONTACT: Dr. David A. Espeseth, Director, 
Licensing and Policy Development, Center for Veterinary Biologics, VS, 
APHIS, USDA, 4700 River Road Unit 148, Riverdale, MD 20737-1237, (301) 
734-8245.

SUPPLEMENTARY INFORMATION:

Background

    The regulations in 9 CFR part 113 pertain to standard requirements 
for the preparation of veterinary biological products. A standard 
requirement consists of test methods, procedures, and criteria 
established by the Animal and Plant Health Inspection Service (APHIS) 
to determine that a veterinary biological product is pure, safe, 
potent, and efficacious and not worthless, dangerous, contaminated, or 
harmful.
    These regulations concerning potency testing of Clostridium 
Perfringens Type C Toxoid and Bacterin-Toxoid in Sec. 113.111 and 
Clostridium Perfringens Type D Toxoid and Bacterin-Toxoid in 
Sec. 113.112 reduce certain test requirements and decrease the cost of 
performing these tests. This has been accomplished without affecting 
the accuracy and reliability of the tests.
    On March 22, 1993, we published a proposed rule in the Federal 
Register (58 FR 15301-15303, Docket No. 92-090-1) to amend the 
regulations in Sec. 113.111 pertaining to Clostridium Perfringens Type 
C Toxoid and Bacterin-Toxoid and in Sec. 113.112 pertaining to 
Clostridium Perfringens Type D Toxoid and Bacterin-Toxoid.
    We proposed to reduce the number of mice needed for serum 
neutralization testing in certain circumstances. Also, the current test 
method uses half of the recommended cattle or sheep dose. The proposed 
rule provided for potency testing of product recommended for use in 
host animal species other than cattle and sheep. The test method in the 
proposed rule provided for recommendations for a variety of host animal 
species by prescribing the use of half of the smallest host animal 
dose.
    Current regulations in Secs. 113.111(c) and 113.112(c) provide for 
at least four of eight rabbits which are initially injected to be bled 
in the potency determination of Clostridium Perfringens Type C Toxoid 
and Bacterin-Toxoid and Clostridium Perfringens Type D Toxoid and 
Bacterin-Toxoid. The amount of antitoxin found in the rabbit sera after 
injection with the toxoid or bacterin-toxoid is proportional to the 
potency of the antigen in the product tested.
    The antitoxin response of vaccinated rabbits is measured by a toxin 
neutralization assay in mice. A standard amount of Clostridium 
perfringens Beta or Epsilon toxin is mixed with a designated amount of 
the test rabbits' sera. The mixture is allowed to neutralize for one 
hour. Swiss white mice are then injected with this toxin-sera mixture 
to determine if the standard amount of toxin was neutralized by the 
test rabbit sera. Since mice are particularly sensitive to these 
toxins, the absence of mouse mortality indicates sufficient toxin 
neutralization and thus an adequate antitoxin response in the rabbits 
tested. The result would indicate an acceptable potency for the toxoid 
or bacterin-toxoid antigen in the product tested.
    Under the current regulations in Secs. 113.111(c) and 113.112(c), 
if four to seven rabbits are bled for potency testing, the sera from 
each rabbit must be assayed individually. This requires the use of at 
least 20 to 35 mice (each rabbit serum is tested in a minimum of 5 
mice) for serum neutralization testing as compared to a minimum of 5 
mice with the single pooled serum sample which was proposed.
    The proposed rule required the use of at least seven rabbits in 
order for the sera to be pooled into a single sample. The potency test 
would then be conducted on the single pooled sample. Pooling the serum 
samples of seven instead of eight rabbits would reduce the number of 
toxin-antitoxin neutralization tests required, the number of mice 
needed, the time spent, and the expense of the procedure.
    We solicited comments concerning our proposal for 60 days ending 
May 21, 1993. We received six comments by that date from manufacturers 
of animal health products and a national trade association. One of the 
commenters supported the proposed rule as written, while five raised 
specific issues concerning the proposed rule. Those comments are 
discussed below.
    One commenter expressed concern that, as proposed, the rule had the

[[Page 31330]]

unintended effect of making the potency test requirements more 
stringent. As a cure, the commenter recommended the use of half the 
cattle dose for testing the potency of all Clostridium Perfringens 
Toxoids.
    Five other commenters also expressed concern about the proposed 
reduction in the volume of rabbit inoculum to half the smallest host 
animal dose. One firm indicated it would be forced to increase antigen 
content in order to pass the more stringent requirement resulting from 
a reduced volume of rabbit inoculum, with the possible negative effect 
on host animal safety.
    Three commenters indicated that the proposed inoculum volumes would 
be incompatible with those in the recently revised standard 
requirements for Clostridium Novyi and Clostridium Sordellii, which 
permitted utilization of the same group of rabbits for testing of sheep 
and cattle product fractions, the only two species addressed under that 
standard requirement. One commenter indicated that there is no need to 
change the volume of the rabbit inoculum under the current regulations.
    Yet another commenter suggested that the volume of rabbit inoculum 
should be half of the largest dose indicated on the label for any 
species of animal for which the product is recommended. The commenter 
argued that this suggestion would not affect the potency test procedure 
for any licensed product, while it would address the dosage to be used 
for alternate species not specifically addressed under the current 
regulations, i.e., goats and swine.
    In response to these comments, APHIS agrees that a volume of rabbit 
inoculum that is half the largest host animal dose for any species of 
animal for which the product is recommended is reasonable and also 
provides for more general indications that are appropriate for products 
not recommended for cattle or sheep. Reference to half of the largest 
host animal dose would, in most cases, result in the same rabbit test 
dosage that is used for testing these products in the current standard 
requirement. The proposal to require half the smallest host animal dose 
would have unnecessarily raised the potency requirement for some 
products and, in contrast to statements made in the proposed rule, 
would have resulted in test procedures that were not consistent with 
recent standard requirements for products containing Clostridium novyi 
and Clostridium sordellii. Therefore, in response to these comments, we 
are amending the regulations in Secs. 113.111 and 113.112, paragraph 
(c)(2), to allow the use of half the largest recommended dose in host 
animals for the rabbit potency testing for any species of animal for 
which the product is recommended. The change in the proposed rule will, 
in most cases, retain the potency test requirement for these products 
at the same level as in the current standard requirement while 
recognizing products that would be used in animals other than cattle or 
sheep.
    In further response to the comment that the standard requirement 
for Clostridium Perfringens should be consistent with those of 
Clostridium Novyi and Clostridium Sordellii, APHIS notes that the 
recently amended standard requirements for Clostridium Novyi and 
Clostridium Sordellii require that the strain of rabbit used for 
potency testing be acceptable to APHIS. APHIS believes that, for 
consistency, the requirement should apply equally to Clostridium 
Perfringens. Therefore, in response to this comment, we are adding the 
requirement in Secs. 113.111 and 113.112, paragraph (c)(2), that the 
strain of rabbit used for potency testing Clostridium Perfringens be 
acceptable to APHIS.
    Therefore, based on the rationale set forth in the proposed rule 
and in this document, we are adopting the provisions of the proposal as 
a final rule, with the changes discussed in this document.

Executive Order 12866 and Regulatory Flexibility Act

    This rule has been determined to be not significant for the 
purposes of Executive Order 12866 and, therefore, has not been reviewed 
by the Office of Management and Budget.
    There are currently some 19 veterinary biologics establishments 
that may be affected by this rule. According to the Small Business 
Administration regulations, many of them would be classified as small 
entities.
    This rule will result in a reduction of the number of mice required 
to perform potency assays. The reduction in the number of mice needed 
will result in a reduction in the total cost of the assays. Therefore, 
the rule should provide an economic benefit to producers of veterinary 
biologics. In addition, this rule clarifies the dosage of rabbit 
inoculum to be used in potency tests for products recommended for 
species other than cattle or sheep.
    Retests may be indicated if less than 80 percent of control mice, 
inoculated with standard antitoxin and 10 L+ doses of 
standard toxin, die in the neutralization test. However, since the 
testing of the pooled serum sample requires fewer mice as compared to 
testing individual serum samples, the number of mice required for a 
retest will be less.
    Manufacturers, as well as the National Veterinary Services 
Laboratories, will benefit from the revisions since they will improve 
efficiency and reduce costs but will not change the accuracy of the 
assays.
    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 12988

    This rule has been reviewed under Executive Order 12988, 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 which must be exhausted 
prior to a judicial challenge to the provisions of this rule.

Paperwork Reduction Act

    This rule contains no new information collection or record keeping 
requirements under the Paperwork Reduction Act of 1995 (44 U.S.C. 3501 
et seq.).

List of Subjects in 9 CFR Part 113

    Animal biologics, Exports, Imports, Reporting and recordkeeping 
requirements.

    Accordingly, 9 CFR part 113 is amended as follows:

PART 113--STANDARD REQUIREMENTS

    1. 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).

    2. Section 113.111 is amended by revising paragraphs (c)(2), 
(c)(3)(i), (c)(3)(ii), (c)(3)(iii), and (c)(5)(iii) to read as set 
forth below, and by removing paragraph (c)(5)(iv).


Sec. 113.111  Clostridium Perfringens Type C Toxoid and Bacterin-
Toxoid.

* * * * *
    (c) * * *
    (2) Each of at least eight rabbits of a strain acceptable to APHIS, 
each

[[Page 31331]]

weighing 4-8 pounds, shall be injected subcutaneously with not more 
than half of the largest recommended dose for any species indicated on 
the product label. A second equivalent dose shall be given not less 
than 20 days nor more than 23 days after the first dose.
    (3) * * *
    (i) At least seven rabbits are required to make an acceptable serum 
pool.
    (ii) Equal quantities of serum from each rabbit shall be combined 
and tested as a single pooled serum.
    (iii) If less than seven rabbits are available, the test is invalid 
and shall be repeated: Provided, That, if the test is not repeated, the 
serial shall be declared unsatisfactory.
* * * * *
    (5) * * *
    (iii) If any mice inoculated with the mixture of serum with 10 
L doses of Standard Toxin die, the serum is considered to 
contain less than 10 International Units per ml, and the serial is 
unsatisfactory.
    3. Section 113.112 is amended by revising paragraphs (c)(2), 
(c)(3)(i), (c)(3)(ii), (c)(3)(iii), and (c)(5)(iii) to read as set 
forth below, and by removing paragraph (c)(5)(iv).


Sec. 113.112  Clostridium Perfringens Type D Toxoid and Bacterin-
Toxoid.

* * * * *
    (c) * * *
    (2) Each of at least eight rabbits of a strain acceptable to APHIS, 
each weighing 4-8 pounds, shall be injected subcutaneously with not 
more than half of the largest recommended dose for any species 
indicated on the product label. A second equivalent dose shall be given 
not less than 20 days nor more than 23 days after the first dose.
    (3) * * *
    (i) At least seven rabbits are required to make an acceptable serum 
pool.
    (ii) Equal quantities of serum from each rabbit shall be combined 
and tested as a single pooled serum.
    (iii) If less than seven rabbits are available, the test is invalid 
and shall be repeated: Provided, That, if the test is not repeated, the 
serial shall be declared unsatisfactory.
* * * * *
    (5) * * *
    (iii) If any mice inoculated with the mixture of serum with 10 
L doses of Standard Toxin die, the serum is considered to 
contain less than 2 International Units per ml, and the serial is 
unsatisfactory.

    Done in Washington, DC, this 3rd day of June 1997.
Donald W. Luchsinger,
Acting Administrator, Animal and Plant Health Inspection Service.
[FR Doc. 97-14996 Filed 6-6-97; 8:45 am]
BILLING CODE 3410-34-P