University of Pittsburgh Prevails in Federal Circuit Patent Case

The University of Pittsburgh was recently involved in an inventorship dispute involving U.S. Patent No. 6,777,231 for “Adipose-Derived Stem Cells and Lattices” that issued August 17, 2004.  The United States Court of Appeals for the Federal Circuit decided on July 23, 2009 that two University of Pittsburgh researchers completed conception of the claimed invention before the appealing researchers contributed their efforts, and therefore are not joint inventors of the claimed invention.

 Drs. Katz and Llull are researchers at the University of Pittsburgh studying adipose (fat) tissue in humans.  In March 2000, the University of Pittsburgh filed an international patent application listing seven named inventors, which issued as U.S. Patent No. 6,777,231.  In October 2004, the University of Pittsburgh filed this action seeking removal of the other five inventors, including Marc H. Hedrick, a REBAR researcher. 

 The district court held a hearing to construe the patent claims.  The term “adipose-derived” was among the constructions disputed.  The REBAR researchers argued that the construction should be limited, while Katz and Llull argued for a plain meaning.  The district court determined that the specification supported the plain meaning.  The district court then found that Katz and Llull had conceived the claimed invention as construed prior to Hedrick’s arrival at the University of Pittsburgh.  The REBAR researchers appealed the construction of “adipose-derived” and the conclusion that they were not joint inventors of the claimed invention.  

  • The inventors named in an issued patent are presumed to be correct.  A party alleging misjoinder of inventors must prove its case by clear and convincing evidence.  The movant must show that the persons to be removed did not contribute to the invention of any of the allowed claims. 


  • Conception is the formation in the mind of an inventor of a definite and permanent idea of the complete and operative invention.  The test for conception is whether the inventor had an idea that was definite and permanent enough that one skilled in the art could understand the invention.  For conception to be complete, an inventor does not have to know that his invention will work.  He must only show that he had the complete mental picture and could describe it with particularity.  (Discovering that the invention actually works is part of its reduction to practice.)  In a joint invention, each inventor must contribute to the joint arrival at a definite and permanent idea of the invention. 

See University of Pittsburgh v. Hedrick et al., No. 2008-1468 (Fed. Cir. July 23, 2009).

 The district court held, and the Federal Circuit affirmed, that clear and convincing evidence existed to show that Katz and Llull conceived of each claim of the invention before the arrival of Hedrick.

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