CAFC Says Generic Blood Pressure Product Won’t Infringe Par Pharma Patents


“Par’s arguments that Eagle would not meet its stability specifications were unsupported by evidence and amounted to little more than ‘speculation,’ the appeals court said.”

In its third precedent patent decision this week, the United States Court of Appeals for the Federal Circuit (CAFC) today upheld a district court’s finding that the Abbreviated New Drug Application (ANDA) of Eagle Pharmaceuticals, Inc. does not infringe two patents owned by Par Pharmaceutical, Inc., Par Sterile Products, LLC and Endo Par Innovation Company, LLC (collectively, Par). The CAFC also upheld the district court’s denial of a declaratory relief that the sale of the proposed generic product would violate.

The patents claimed by Par are US Patent Nos. 9,744,209 and 9,750,785. They cover Par’s product Vasostrict, which is used to treat patients with critical low blood pressure and which Par began selling in 2014. The claims of both patents require the vasopressin composition to have a rounded pH between 3.7 and 3.9.

Eagle filed its ANDA in 2018, specifying that the pH range of its product would be between 3.4 and 3.6 after rounding. It also stated in its stability specification, “which defines the properties of the product during its shelf life”, that the pH would remain between 3.4 and 3.6. Par sued Eagle in the United States District Court for the District of Delaware, alleging infringement of both patents and seeking a declaration of infringement. Eagle told the district court that its proposed generic product would meet all claimed claim limitations except for the claimed pH range of 3.7 to 3.9.

“Upward Drift” Analysis

In response, Par argued that “real world evidence” “shows that the pH of Eagle’s product increases over time” and that products with a pH of 3.64, which is only 0, 01 below the rounded front counterfeit range, so would inevitably drift upward. the infringing range. The District Court’s investigation, however, found no evidence of such an upward trend and, in any case, the stability specification “imposed an additional constraint that the product offered by Eagle must maintain a pH within between 3.4 and 3.6 from the time of its distribution. throughout its shelf life.

In its discussion, the CAFC stated that the ANDA survey is controlled by the ANDA specification, which should “define[e] a generic drug offered in a way that directly addresses the issue of counterfeiting. If it doesn’t clearly address the issue of infringement, the court can look to other data, but in this case the CAFC said “the investigation begins and ends with Eagle’s ANDA specification “. Par’s arguments that Eagle would not meet its stability specifications were unsupported by evidence and amounted to little more than “speculation”, the appeals court said, and were ultimately insufficient to establish infringement.

No clear errors

As for the motion for declaratory relief, Par had argued on appeal that “the district court erred in finding no discernible drift in pH elevation and in dismissing the relevance of even minor pH fluctuations.” But that conclusion was not a “clear error”, the CAFC said, as it conducted a thorough analysis and reviewed the evidence from both sides, including Eagle’s expert, who found that “although the measures fluctuated over time, there was no discernable trend”. – and certainly not an inevitable upward trend – in fluctuations. The CAFC also rejected Par’s claims that the district court’s reliance on post-optimization data was in error, explaining that this amounted to a challenge to the court’s assessment of the evidence and not a clear belief that he had made a mistake.

Finally, Par argued that the district court ignored Eagle’s release specification, which indicates that a product could be released at a pH of 3.64, because, had it considered the specification of release, he would have concluded that any minor upward fluctuation would violate. But the CAFC disagreed:

“Par continues to incorrectly display the version specification in isolation. Eagle’s ANDA is not limited by its version specification only – it is also limited by the stability specification and manufacturing process…. As noted above, Eagle is bound by its statements to the FDA that it will manufacture its products according to the optimized process and that the pH of its products will remain between 3.4 and 3.6.

The court therefore found that Eagle’s ANDA described a non-infringing product and upheld the district court’s findings.

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