Animal & Veterinary

ANADA 200-134 Fertagyl® - original approval

Approval Date: June 17, 1996





Intervet Inc.
405 State Street
P.O. Box 318
Millsboro, DE 19966-0318

Generic Name:

gonadorelin diacetate tetrahydrate injection

Trade Name:


Marketing Status:


  1. Established Name: gonadorelin diacetate tetrahydrate injection
  2. Trade/Proprietary Name: Fertagyl ®
  3. Dosage Form: sterile injectable solution
  4. How Supplied: 2mL and 20 mL vials
  5. How Dispensed:Rx
  6. Amount of Active Ingredient: 43 mcg/mL gonadorelin equivalent to 50 mcg/mL gonadorelin diacetate tetrahydrate
  7. Route of Administration: Intramuscular or intravenous in cattle
  8. Species: Dairy cattle (females of breeding age)
  9. Pioneer Product/"Listed" Product: Cystorelin®, NADA 098-379, Sanofi Animal Health
  10. Date of Approval: June 17, 1996


Fertagyl ® is indicated for the treatment of ovarian follicular cysts in dairy cattle. Ovarian cysts are non-ovulated follicles with incomplete luteinization which result in nymphomania or irregular estrus.

Historically, cystic ovaries have responded to an exogenous source of luteinizing hormone (LH) such as human chorionic gonadotropin. Fertagyl ® initiates release of endogenous LH to cause ovulation and luteinization.



The recommended intramuscular or intravenous dosage of Fertagyl ® is 2 mL/cow, containing 86 mcg gonadorelin (equivalent to 100 mcg gonadorelin diacetate tetrahydrate).


Under the provisions of the Federal Food, Drug, and Cosmetic Act, as amended by the Generic Animal Drug and Patent Term Restoration Act, (53 FR 50460, December 15, 1988, First GADPTRA Policy Letter) an abbreviated new animal drug application (ANADA) may be submitted for a generic version of an approved new animal drug (pioneer product). New target animal safety data, drug effectiveness data, and human food safety data (other than tissue residue data) are not required for approval of an ANADA. An ANADA relies on the target animal safety, drug effectiveness, and human food safety data in the pioneer's new animal drug application. Ordinarily, the ANADA sponsor shows that the generic product is bioequivalent to the pioneer. If bioequivalence is demonstrated through a clinical end-point study, then a tissue residue study to establish the withdrawal time for the generic product is also required. For certain dosage forms, the agency will grant a waiver from conducting an in vivo bioequivalence study (55 FR 24645, June 18, 1990; Fifth GADPTRA Policy Letter; Bioequivalence Guideline, April 1990).

Based upon the formulation characteristics of the generic product, Intervet Inc. was granted a waiver from conducting an in vivo bioequivalence study for gonadorelin diacetate tetrahydrate. The generic and pioneer products contain the same active and inactive ingredients and are parenteral solutions.


A tolerance has not been established for gonadorelin diacetate tetrahydrate.

Withdrawal Time
When a waiver of in vivo bioequivalence testing is granted, the withdrawal times are those previously assigned to the pioneer product. A zero withdrawal is applied to gonadorelin diacetate tetrahydrate.

Regulatory Method for Residues
Since gonadorelin is approved with a zero withdrawal, an official analytic method is not needed.


This ANADA submitted under section 512(b) of the Federal Food, Drug, and Cosmetic Act satisfies the requirements of section 512(n) of the act and demonstrates that gonadorelin diacetate tetrahydrate injection when used under the proposed conditions of use, is safe and effective for its labeled indications.

The following generic labeling and currently approved pioneer labeling are attached.

  1. Facsimile bottle label and insert for generic gonadorelin diacetate tetrahydrate - Fertagyl ® , gonadorelin 43 mcg/mL, equivalent to 50 mcg/mL gonadorelin diacetate tetrahydrate in 2 mL (single dose) and 20 mL (multiple dose) vials
  2. Approved pioneer vial label and insert for gonadorelin diacetate tetrahydrate - Cystorelin ® , gonadorelin diacetate tetrahydrate 50 mcg/mL, 2 mL and 10 mL vials.

Copies of these labels may be obtained by writing to the:

Freedom of Information Office
Center for Veterinary Medicine, FDA
7500 Standish Place
Rockville, MD 20855

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