Last month the Federal Circuit issued its opinion in Salix Pharmaceuticals, Ltd. v. Norwich Pharmaceuticals Inc., a patent case that attracted an amicus brief. In this case, the Federal Circuit reviewed a judgment by the District of Delaware, which held that Norwich infringed certain patent claims but that other claims were invalid for obviousness. After Norwich amended its Abbreviated New Drug Application to remove the infringing indication, Norwich sought to modify the judgment, contending the amendment negated any possible infringement. The district court, however, denied its motion. The Federal Circuit, in an opinion authored by Judge Lourie that was joined by Judge Chen, affirmed the judgment of the district court. Judge Cunningham, however, filed a dissenting opinion. This is our opinion summary.
Judge Lourie began by highlighting the procedural and factual background of the case:
Rifaximin, the active ingredient in Salix’s commercial product Xifaxan®, has been widely used as an antibiotic for decades . . . . Norwich sought to market a generic version of rifaximin and, in 2019, filed an ANDA for 550 mg tablets with the same indications as Xifaxan, certifying pursuant to 21 U.S.C. § 355(j)(2)(vii)(IV) that Salix’s rifaximin patents were invalid. . . . By the time of trial, the case had been streamlined to three groups of patents: the ’573, ’195, and ’397 patents, directed to treating HE (“the HE patents”); the ’569 and ’667 patents, directed to treating IBS-D with 550 mg rifaximin three times a day (1,650 mg/day) for 14 days (“the IBS-D patents”); and, the ’199 and ’206 patents, directed to rifaximin form β (“the polymorph patents”). . . . Following a bench trial, the district court held that Norwich infringed the HE patents’ claims and had failed to establish their invalidity. . . . The court also held that Norwich’s ANDA infringed the IBS-D and polymorph patents, but that those patents’ claims would have been obvious over certain prior art. . . . Salix appealed those invalidity holdings. As part of the entered judgment, the district court ordered that the effective date of a final approval of Norwich’s ANDA should not precede October 2029, which is the latest expiration date associated with the HE patents. . . . Norwich then amended its ANDA in an attempt to remove the infringing HE indication and moved to modify the judgment under Federal Rule of Civil Procedure 60(b), asserting that the amendment negated any possible infringement. The court denied Norwich’s motion, and Norwich cross-appealed.
Judge Lourie first addressed “Salix’s contention that the district court erred in concluding that the asserted claims of the IBS-D patents would have been obvious over the asserted prior art.” He noted that “Norwich challenged the IBS-D claims’ validity by asserting as prior art references a clinical trial protocol . . . (‘the Protocol’) and a 2006 journal article (‘Pimentel’).” He made it clear that “[t]he district court did not clearly err in finding that a skilled artisan would have looked to both of those references, considered their limits, and had a reasonable expectation of success as to the efficacy of 550 mg TID dosing.”
Judge Lourie then turned to Salix’s argument “that a Press Release issued by Salix in a filing with the Securities and Exchange Commission less than a year before the patents’ priority date was not prior art because Norwich failed to establish that it was ‘by others’ as required by pre-AIA 35 U.S.C. § 102(a).” Responding to this argument, Judge Lourie explained that the court “need not decide whether or not the Press Release was prior art because, even assuming that it was not, the Protocol and Pimentel alone established the obviousness of the claims.”
Judge Lourie next addressed “Salix’s contention that the district court clearly erred in finding that there would have been a reasonable expectation of success in obtaining the rifaximin form β.” He noted that “[t]he scope and content of the prior art here includes preparations of crystalline rifaximin, which expert testimony supports would have yielded the β form of rifaximin.” According to Judge Lourie, the “difference between the prior art and the claims is thus effectively nothing more than the performance of routine characterization to identify the polymorphic forms that result from the known . . . processes.” “Because we affirm the court’s holding that the polymorph patent claims would have been obvious over the asserted prior art,” Judge Lourie explained, “we need not consider Norwich’s separate argument that the polymorph claims would have also been invalid as inherently anticipated.”
Turning to Norwich’s cross-appeal, Judge Lourie addressed “Norwich’s arguments regarding the district court’s interpretation of 35 U.S.C. § 271(e)(4)(A) in ordering that a final approval of Norwich’s ANDA could not be effective before the HE patents expired.” Judge Lourie rejected Norwich’s arguments, highlighting how the fact that “the ANDA . . . recited a non-patent-protected indication does not negate the infringement resulting from the ANDA’s submission.” Judge Lourie noted, however, how “[t]he order appropriately said nothing that would prevent approval of a new non-infringing ANDA.”
Lastly, Judge Lourie responded to Norwich’s final argument concerning its motion “to modify the judgment under Federal Rule of Civil Procedure 60(b).” Judge Lourie explained how “a district court has the discretion, not the obligation, to modify a final judgment in view of a post-judgment ANDA amendment.” He agreed with the district court that “simply asserting that a patented indication has been carved out of an ANDA application does not necessarily satisfy the judgment or entitle the applicant to direct entry to the market.”
As a result of its analysis, the Federal Circuit affirmed the district court’s judgment.
As mentioned, Judge Cunningham dissented in part. She explained that she “would vacate the district court’s judgment that the asserted claims of the IBS-D patents are obvious and remand for further proceedings.” According to Judge Cunningham, “[t]he evidence cited by the district court does not support its finding that a skilled artisan would have a reasonable expectation of success for the claimed dosage.” In particular, she argued, “the district court clearly erred in relying on the RFIB 2001 Press Release and other references that do not teach the claimed dosage.” “In summary,” she explained, she “would vacate the district court’s judgment that the asserted claims of the IBS-D patents were obvious and remand for further proceedings.” And, on remand, she “would order the district court to consider in the first instance the teachings in the additional prior art references.”