CAFC Affirms District Court’s Denial of Mandatory Stay for ITC Respondent Who Voluntarily Dismissed Complaint

The U.S. Court of Appeals for the Federal Circuit (CAFC) today issued a precedential decision in Ascendis Pharma A/S v. BioMarin Pharmaceutical Inc., affirming a district court order that upheld the U.S. District Court for the Northern District of California decision denying Ascendis’s motion for a mandatory stay under 28 U.S.C. § 1659(a)(2). The ruling concluded that Ascendis was not entitled to a mandatory stay because Ascendis voluntarily dismissed its original complaint and filed a virtually identical refiled complaint to restart the statutory deadline. Judge Stoll authored the opinion, joined by Judges Lourie and Chen.

On appeal, the dispute centered on whether a respondent in a United States International Trade Commission (ITC) proceeding may seek a mandatory stay of its refiled declaratory judgment action involving the same issues, even though it had previously filed a declaratory judgment action and missed the deadline for seeking a stay. Ascendis and BioMarin develop treatments for children with achondroplasia, and BioMarin owns U.S. Patent No. RE48,267, which covers certain variants, including its Food and Drug Administration (FDA) approved treatment, Voxzogo.

On March 31, 2025, Ascendis filed a New Drug Application (NDA) with the FDA for its drug, TransCon CNP. The next day, BioMarin filed a complaint with the ITC against Ascendis, seeking to remedy the alleged unlawful importation of drug products that infringe its patent. BioMarin contended that the imported quantity of TransCon CNP exceeded any quantity solely for uses reasonably related to the development and submission of information to the FDA. Ascendis responded that it had not imported TransCon CNP for any reason other than obtaining FDA approval.

Ascendis filed a complaint for declaratory judgment of non-infringement in the district court on April 11, 2025. Ascendis first sought a speedy hearing, then voluntarily dismissed and refiled a nearly identical declaratory judgment action to pursue a mandatory stay. It later moved for that stay, which BioMarin opposed as untimely while seeking a discretionary stay instead. The court granted BioMarin’s discretionary stay and denied Ascendis’s motion as moot.

Ascendis appealed, asserting that the district court erred in denying a mandatory stay and that the CAFC had jurisdiction under the collateral order doctrine. The CAFC first considered whether Ascendis had Article III standing. Ascendis asserted standing because “BioMarin repeatedly stated that upon FDA approval of TransCon CNP, BioMarin could seek to lift the discretionary stay and pursue a preliminary injunction.” BioMarin responded that the purported injury was speculative, and the CAFC agreed with Ascendis, noting that had the district court granted a mandatory stay, lifting it would not have been an option. The CAFC observed that the FDA approved Ascendis’s drug shortly following oral argument. Shortly after FDA approval, BioMarin informed Ascendis of its intent to file a motion for a preliminary injunction before the ITC trial. The CAFC held that Ascendis demonstrated a “controversy of sufficient immediacy and reality” to satisfy Article III standing.

The CAFC next addressed whether it had jurisdiction under the collateral order doctrine, agreeing with Ascendis that the appeal met all three requirements. The district court made a conclusive determination on the disputed question. Then, granting a discretionary stay and denying a mandatory stay resolves an important issue completely separate from the merits. Moreover, the district court order cannot be effectively reviewed on appeal from a final judgment, because a mandatory stay is intended to prevent litigation while an ITC case is pending.

Addressing whether the district court erred in denying the motion for a mandatory stay, the CAFC determined that any error by the district court was harmless. A discretionary stay that can be lifted should circumstances change is not the same as a request for a mandatory stay that cannot be lifted until a final decision in the ITC proceedings. Accordingly, the grant of a discretionary stay did not moot the request for a mandatory stay.

However, the error was harmless because Ascendis was not entitled to a mandatory stay. Interpreting the statutory text under the backdrop of the common law, which “prohibits the use of voluntary dismissal as an indirect way to avoid the explicit requirements of other rules.” Thus, the CAFC concluded that “the district court action” refers to the original action. Ascendis voluntarily dismissed the original complaint and filed a virtually identical refiled complaint to restart the 30-day deadline. The CAFC found that “these circumstances fit squarely within the common-law principle of prohibiting the use of voluntary dismissal to accomplish indirectly what cannot be accomplished directly.”

Ascendis argued that if Congress intended to prohibit respondents from refiling to seek a statutory stay, it would have included express language. The CAFC found it “too speculative” to infer that the use of the term “filed” instead of “initially filed” meant that Congress intended for respondents to be able to refile their declaratory judgment action to get around the 30-day deadline. The CAFC noted that an interpretation that would allow Ascendis to refile its complaint to get around the 30-day deadline does not “avoid abuse” or “encourage prompt adjudication.” Ultimately, the CAFC affirmed the district court decision.