Fish & Richardson principals, Michael Amon and Todd Miller, successfully defended San Diego-based medical device company NuVasive Inc. in a recent infringement case involving a patent said to cover its living-cell based implant used to speed-up bone fusion, predominantly in patients undergoing spinal fusion surgery.

On February 17, a California federal court found that NuVasive did not infringe upon the patent (U.S. Patent No. 5,676,146) held by Warsaw Orthopedic Inc.—part of Minneapolis-based Medtronic—for a “surgical implant containing a resorbable radiopaque marker and method of locating such within a body.”

Warsaw alleged that NuVasive’s Osteocel Plus—a cellular allograft product, which is made up of living cells, including mesenchymal stem cells and osteoprogenitor cells—infringed on its patent covering a uniform mixture of cadaveric bone particles that makes the implant visible under X-ray.

After the completion of extensive expert discovery both in the district court and in the Patent Office, NuVasive’s motion for summary judgement of non-infringement, argued by Amon and Miller, was granted by U.S. District Court Judge Cathy Ann Bencivengo, who found that testimony of Warsaw’s own experts could not support its infringement claims. Bencivengo found the asserted Warsaw claim was not met by NuVasive’s Osteocel Plus product.

The case was filed in 2012 and coupled with another alleged patent infringement for a spinal implant.

Following issuance of the court’s order on claim construction, NuVasive asked the U.S. Patent and Trademark Office for ex parte re-examination of the Warsaw patent. The USPTO initially rejected Warsaw’s asserted claims based on NuVasive’s prior art. However, after receiving testimony from Warsaw’s experts, the office reversed the decision.

The experts said NuVasive’s prior art differed from the patented implant design because the patent required the radiopaque materials to “be uniformly distributed within a substantially uniform admixture with the radiolucent material.” They stressed the material’s particles must be uniformly arranged so that the entire implant can be seen in an X-ray.

Back in district court, Warsaw’s reliance on this expert witness testimony could not be aligned with Warsaw’s contention that Osteocel Plus met the “uniformly distributed” claim limitations.

“The sole evidence Warsaw offers to support its infringement claims is an expert report that is based on a construction of the claims that is inconsistent with the construction argued by Warsaw through (expert witness) Dr. Sachs and adopted by the patent office in the re-examination proceeding to overcome prior art,” the decision said.

Bencivengo found that while NuVasive’s Osteocel Plus was a mixture of the opaque and radiolucent material, that there was no evidence these materials were uniformly arranged or infringing upon Warsaw’s patent.