District of New Jersey Finds the Claim Term “Homogeneous Matrix” Definite

U.S. District Judge Renee Marie Bumb recently found two of three patents covering the epilepsy drug Oxtellar XR® to be valid and infringed.  Supernus Pharms. Inc. v. Actavis Inc. et al., Civ. No. 13-cv-4740 (D. N.J. Feb. 5, 2016).  As part of her opinion following a bench trial, Judge Bumb ruled that the term “homogeneous matrix,” which was present in every asserted claim, was not indefinite under the Nautilus “reasonable certainty” standard.

As this blog has previously discussed, the Supreme Court’s Nautilus decision significantly changed the standard for indefiniteness.  However, Judge Bumb’s decision shows that indefiniteness can still be an uphill battle for a patent challenger.

Each asserted claim of the Oxtellar XR® patents required a “homogeneous matrix” comprising the active pharmaceutical ingredient oxcarbazepine, a matrix forming polymer, a solubility enhancing agent, and a release promoting agent.  (Order at 5.)  Judge Bumb construed “homogeneous matrix” as “a matrix in which the ingredients or constituents are uniformly dispersed.”  (Order at 17.)

Actavis argued that the term was indefinite because the specification and the prosecution history provide no guidance on how to determine whether a matrix is “homogeneous.”  (Order at 133.)  Actavis offered expert testimony stating that there is no generally recognized standard for determining whether a distribution of ingredients was “uniform” or not.  (Order at 134.)  To demonstrate this, Actavis compared the distribution of the claimed constituents in its tablets to the distribution in Plaintiff’s tablets using chemical imaging, but its expert explained that there is no recognized chemical imaging metric for identifying what is a “homogenous” matrix versus a non-homogeneous one.[1]

Judge Bumb disagreed.  She concluded that persons skilled in the art understood that “homogeneity varied in degrees” and that “perfect homogeneity was not achievable because perfect molecular uniformity in a pharmaceutical formulation was not possible.”  (Order at 134.)  Judge Bumb also noted that the specification disclosed a manufacturing process that the inventors used to produce the claimed “homogeneous” matrix.  (Order at 135.)  Finally, Judge Bumb explained that “chemical imaging is a standard that confirms homogeneity, but it is not essential to the Patents-in-Suit to survive an indefiniteness challenge.”  (Order at 135.)

This decision shows that even under Nautilus, claim terms that are admittedly subject to some uncertainty may still be found definite enough to pass muster.


[1] As part of Judge Bumb’s infringement findings, she acknowledged that chemical imaging showed that Actavis’s tablets may be “less homogeneous” than the Plaintiff’s tablets but found that Actavis’s tablets were still “homogeneous” for the purposes of the claims.  (Order at 57.)