A licensee seeking a declaratory judgment of noninfringement bears the burden of proof in the limited circumstance where the license prevents the patentee from asserting a counterclaim for infringement.

The patentee entered an agreement with the accused infringer which allowed the accused infringer to have a license while seeking a declaratory judgment of noninfringement. Because the accused infringer had a license, the patentee could not assert a counterclaim for infringement. At trial, the district court held that the patentee had the burden to prove infringement, that it failed to meet that burden, and that the accused infringer was entitled to its judgment. The patentee appealed, and the Federal Circuit vacated and remanded. 

The court reiterated that in the usual case a patentee who files a complaint or counterclaim alleging patent infringement bears the burden of proving that infringement. In this case, however, only the accused infringer could seek relief. The patentee could not assert a counterclaim for infringement due to the continued license agreement. Following MedImmune, Inc. v. Genetech, Inc. 549 U.S. 118 (2007), the court found that because the license shielded the accused infringer from liability for infringement, the patentee should not be dragged into litigation and forced to prove what it already resolved by license. Therefore, the court held that where the accused infringer has a license and seeks a declaratory judgment of noninfringement, and the license prevents the patentee from asserting a counterclaim for infringement, the accused will have the burden of proof on noninfringement. 

A copy of the opinion can be found here.