Judge Denies Natera Motion to Invalidate CareDx, Stanford Patents

This article has been updated to clarify Natera's actions after it refiled its motion to invalidate CareDx's patents in April, as well as to correct a statement on John Quackenbush's views of the claims asserted in Stanford's patents.

NEW YORK – The United States District Court for the District of Delaware has denied a motion made by Natera to declare invalid three patents held by Stanford University and licensed exclusively to CareDx.

The motion was the latest salvo in a patent infringement suit originally filed by CareDx and Stanford against Natera in March 2019, claiming that Natera had infringed on US Patents Nos. 9,845,497 and 8,703,652. The patents cover methods of cell-free DNA analysis for noninvasive monitoring of organ transplant rejection, which CareDx uses as the basis for its AlloSure organ transplant diagnostics. CareDx asserted that Natera had infringed on that intellectual property through its marketing and performance of a kidney transplant rejection test to analyze cell-free DNA from transplant patients to inform rejection.

At that time, CareDx levied two counts of infringement against Natera and asked the court to grant it a judgment saying either that infringement had occurred or that the '497 and '652 patents were valid.

A year later, CareDx and Stanford amended their suit to claim that Natera had also infringed on US Patent No. 10,329,607, which covers noninvasive monitoring of organ transplant rejection through cell-free DNA analysis. It said Natera had infringed on that patent by performing its Kidney Transplant Rejection test in the US.

CareDx and Stanford asked for a jury trial, and also asked the court to render judgment that Natera had infringed the three patents. But the filing of the amended complaint also caused the court to set aside a previously filed recommendation from a magistrate judge that the court deny a motion from Natera to dismiss the lawsuit.

Natera had asserted that the subject matter in the '497 and '652 patents was ineligible for patenting and asked the court to dismiss CareDx's case, but a magistrate judge recommended that this motion be denied. However, the filing of the amended complaint rendered the motion to dismiss moot, and the court denied it without prejudice, giving Natera leave to refile it based on the plaintiffs' amended complaint.

Indeed, Natera did just that on April 9, but later withdrew that motion in order to file a motion, at the court's invitation, for a summary judgement of invalidity on all three patents, "because they claim unpatentable subject matter."

That motion was filed in June, accompanied by declarations from Harvard professor and genome scientist John Quackenbush asserting that neither the written descriptions nor the claims of the subject matter that Stanford and CareDx are claiming to patent "disclose nonconventional techniques for performing genotyping and/or multiplex/ high-throughput sequencing, individually or in combination," according to the company's brief.

However, the judge denied the motion, noting that CareDx and Stanford had pointed to several techniques in the patent that they believed were nonconventional. The plaintiffs also submitted a declaration from their own expert and cited several scientific articles in support of their position, discussing the limitations and "nascent nature" of some of the disclosed techniques, the judge said.

"Because there is a disputed fact that Natera has said is material to its summary judgment motion, I will deny the motion," the judge wrote in the ruling.

In an email to GenomeWeb, CareDx CEO Reginald Seeto said the company welcomes the ruling, adding that upholding the patents "is in the interest of future innovation in transplantation and patient care. [We] have invested years to bring AlloSure to kidney transplant patients. It is great to see that the case is moving forward."