Second, the court held that in BPCIA litigation, a biosimilar applicant is not limited to the invalidity positions disclosed in its "section 3B" contentions to the reference-product sponsor during the patent dance. In its motion, Genentech, the reference product sponsor (RPS), argued that because Amgen "failed to provide 'such other information' [in addition to Amgen's aBLA] that describes its biosimilar manufacturing process," as required in the information exchange of the BPCIA patent dance, "Amgen is barred… from asserting counterclaims that seek a declaratory judgment" that Genentech's patents are invalid, unenforceable, or not infringed. The court held that it was unnecessary to resolve whether Amgen had satisfied the disclosure requirements of the patent dance because "the filing of counterclaims does not constitute 'bringing an action'" under the statute.