Skip to Content

King Pharmaceuticals Files Citizen Petition with FDA Asserting ZymoGenetics Has Not Submitted Adequate Data for Approval of Its Recombinant Thrombin Product

BRISTOL, Tenn.--(BUSINESS WIRE)--Nov 1, 2007 - King Pharmaceuticals, Inc. (NYSE:KG) today announced it filed a Citizen Petition(1) with the U.S. Food and Drug Administration (FDA) regarding the proper application of product licensure and labeling standards for follow-on topical thrombin products. The petition also raises specific issues concerning the application of these standards to a biologics license application (BLA) filed by ZymoGenetics for a recombinant topical thrombin product which is currently under review by the FDA.

The petition asserts that ZymoGenetics is pursuing an abbreviated pathway to approval of its recombinant thrombin in violation of the law regarding BLA approvals. This assertion is based on ZymoGenetics' public statements and information regarding its clinical data showing limited patient exposure to recombinant thrombin. In addition, King believes there is a lack of supportive safety and efficacy data for ZymoGenetics' single phase III trial.

Federal law requires BLA applicants to independently demonstrate the safety, purity, and potency of biologic products without reliance on data from other products. Because the ZymoGenetics clinical program has resulted in only a limited number of patients exposed to its product, King believes that ZymoGenetics is relying on data from non-recombinant thrombin products, including King's bovine thrombin product THROMBIN-JMI(R) (thrombin, topical, bovine, USP), to demonstrate safety, purity and potency, contrary to law.

King is asking the FDA to adhere to its long-held scientific and legal requirements that, with limited exceptions, BLA approvals be based on at least two adequate and well-controlled clinical studies and that these studies each feature clinically meaningful efficacy endpoints. At a minimum prior to approval, the FDA should require at least one well-controlled phase III study that includes clinically relevant safety and efficacy endpoints and patients re-exposed to recombinant thrombin.

Further, King asks that should scientific and legal requirements eventually be met for recombinant thrombin approval, the FDA should prohibit labeling that would allow comparative superiority claims, unless those claims are substantiated by evidence derived from adequately powered comparative clinical trials.

Finally, the petition requests that the FDA confirm that it will require sponsors of all thrombin products, whenever discussing observed immunological changes associated with product use - such as the incidence of antibody formation--to include a statement that the clinical relevance of such findings remains unknown. This is consistent with ZymoGenetics' published findings that despite differential incidence of antibody formation between recombinant thrombin and THROMBIN-JMI(R), the products demonstrated equivalent safety.

King Pharmaceuticals markets Thrombin-JMI(R), an active topical hemostat. Thrombin-JMI(R), a bovine-sourced product, is indicated as an aid to hemostasis whenever oozing blood and minor bleeding from capillaries and small veins is accessible, or in conjunction with an absorbable gelatin sponge, USP. Since its approval more than 12 years ago, Thrombin-JMI(R) has been used in an estimated 12 million patient procedures.

About King Pharmaceuticals(R), Inc.

King Pharmaceuticals(R), Inc., headquartered in Bristol, Tennessee, is a vertically integrated branded pharmaceutical company. King, an S&P 500 Index company, seeks to capitalize on opportunities in the pharmaceutical industry through the development, including through in-licensing arrangements and acquisitions, of novel branded prescription pharmaceutical products in attractive markets and the strategic acquisition of branded products that can benefit from focused promotion and marketing and product life-cycle management.

Important Safety Information

Because of its action in the clotting mechanism, Thrombin-JMI(R) must not be injected or otherwise allowed to enter large blood vessels. Extensive intravascular clotting and even death may result.

Please see the full Prescribing Information for Thrombin-JMI(R) for a complete listing of the indications, contraindications, precautions and warnings, including boxed warning regarding possible abnormalities in hemostasis, which is available at

(1) A Citizen Petition is a regulatory mechanism through which any person may request that FDA take or refrain from taking any administrative action. Upon the filing of a Citizen Petition, FDA opens a public docket to which any interested person may submit comments.

Thrombin-JMI(R) is a registered trademark of King Pharmaceuticals Research and Development, Inc., a wholly owned subsidiary of King Pharmaceuticals(R), Inc.


King Pharmaceuticals, Inc.
James E. Green, 423-989-8125
Executive Vice President, Corporate Affairs
David E. Robinson, 423-989-7045
Senior Director, Corporate Affairs

Posted: November 2007