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Memorandum


    To:
      File , BLA, STN 125284/0 , Antithrombin alfa
      GTC Biotherapeutics , Inc. (License # 1794)

    From:
      Chiang Syin, Ph.D., Chief, CBER/OCBQ/DMPQ/MRB II, HFM-676

    Subject:
      Categorical exclusion under 21 CFR § 25.31(c)

    Through:
      Laurie P. Norwood , M.S., Deputy Director, CBER/OCBQ/DMPQ

I have reviewed pertinent sections of the Biologics License Application (BLA) 
(STN BL 125284/0 ) from GTC Biotherapeutics, Inc. (GTC) submitted for the 
manufacture of Antithrombin alfa for restoration of human plasma antithrombin 
levels to normal in patients diagnosed with congenital antithrombin deficiency. 
For patients with this condition, treatment is typically administered only once 
or a few times in a patient's life with treatment usually occurring over a 
period of several days. I find that the request for a categorical exclusion from 
an environmental assessment under 21 CFR 25.31(c) is justified because this 
product falls into the category of substances that occur naturally in the 
environment and the action (approval of the BLA) would not alter significantly 
the concentration or distribution of the substance, its metabolites, or 
degradation products in the environment.

In addition, FDA's Center For Veterinary Medicine (CVM) (based on information 
submitted by GTC) has prepared an Environmental Assessment (EA), pursuant to 21 
CFR 25.20(m) and 21 CFR 25.40, concerning GTC's new animal drug application 
(NADA) for the rDNA construct that directs the expression of human antithrombin 
III (ATryn) in the milk of lactating does (goats). CVM has issued a finding of 
no significant impact, 21 CFR 25.41, stating that the approval of GTC's NADA 
will not significantly affect the human environment.

 ___________        ___________________________________________
 

Date                                Chiang Syin, Ph.D., HFM-676

 

Concurrence

___________          ___________________________________________

Date                                 Laurie P. Norwood, M.S.
                                        Deputy Director
                               Division of Manufacturing and Product Quality

 