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U.S. Department of Health and Human Services

Animal & Veterinary

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PMF 005-637 - Walleye - Effectiveness Letter

INAD 010974 P 0004

January 30, 2004

USGS, Upper Midwest Environmental Sciences Center
Attn: William H. Gingerich, Ph.D.
Interim Registration Officer
2630 Fanta Reed Road
La Crosse, WI 54603

Dear Dr. Gingerich:

By letter dated January 28, 2003, you submitted an effectiveness study report and draft labeling to the Investigational New Animal Drug (INAD) file, INAD 010974, for chloramine-T. The drug is proposed as an antibacterial agent in freshwater-reared finfish. The submission requested review of a study to determine the effectiveness of chloramine-T to control mortality associated with external columnaris disease due to Flexibacter columnare in walleye, and review of draft labeling.

Based on the information in this submission and the information contained in INAD 010974, the Division of Therapeutic Drugs for Food Animals considers the EFFECTIVENESS technical section to be complete for the use of chloramine-T at concentrations of 10 and 20 mg/L of water for 60 minutes on alternate days three times to control mortality in walleye due to external columnaris disease caused by Flexibacter columnare. Please provide a brief chronology of our correspondence pertaining to this technical section and a copy of this letter in Section 8, EVIDENCE TO ESTABLISH SAFETY AND EFFECTIVENESS, of your Administrative New Animal Drug Application (NADA).

A final decision on whether the application can be approved will be made when all the data for all technical sections submitted as part of an Administrative NADA, NADA, or supplemental NADA are viewed as a whole and it is determined that:

1) the information contained in and referenced by the application supports approval;
2) the GMP status of each manufacturing facility is current and satisfactory;
3) if a claim for categorical exclusion was made, conditions for the categorical exclusion are still applicable;
4) there is no new information that would preclude the approval of the application.


1. Percent mortality was re-analyzed using a generalized linear mixed model with a random tank effect via the NLMIXED procedure in SAS. An underlying binomial distribution with a logit link was used. Our statistician felt that the NLMIXED model was the most appropriate since it allowed for the inclusion of random effects. Because the proposed claim is for control of mortality, the results should be reported using mortality rather than survival. The following table should be included in the Freedom of Information Summary.

Chloramine-T Concentration (mg/L)Cumulative MortalityPercent Cumulative Mortality
104443.1 (p=0.022)
206764.7 (p=0.044)

2. Comments regarding the draft label will be deferred until the safety and effectiveness technical sections are complete for the proposed claim.

Future correspondence regarding your submission to the Investigational New Animal Drug file should include the date of this correspondence and our file number, INAD 010974
P 0004. A copy of this technical section complete letter should be included in the Administrative NADA.

If you need further information regarding this letter, please contact Dr. Donald Prater, Leader, Aquaculture Drugs Team, at 301-827-7567.

Sincerely yours,

Joan C. Gotthardt, D.V.M.
Director, Division of Therapeutic
Drugs for Food Animals
Office of New Animal Drug Evaluation
Center for Veterinary Medicine