Ascendis Pharma A/S v. Biomarin Pharmaceutical Inc.
4:25-cv-05696
N.D. Cal.Sep 9, 2025Background
- Ascendis and BioMarin are biopharma competitors developing treatments for achondroplasia; BioMarin markets Voxzogo and holds reissued U.S. Patent No. 48,267 covering certain CNP variants.
- Ascendis filed an NDA for TransCon CNP on March 31, 2025; BioMarin filed an ITC complaint the next day alleging infringing imports of CNP variants.
- Ascendis previously filed a declaratory judgment action (Prior Action) asserting a safe-harbor defense, then voluntarily dismissed it and refiled the instant declaratory judgment action seeking a stay pending the ITC.
- Ascendis moved for a mandatory stay under 28 U.S.C. § 1659(a); BioMarin opposed timeliness of that statutory stay and alternatively moved for a stay under the court’s Landis authority.
- The court found both parties favored a stay but concluded Ascendis engaged in procedural gamesmanship by dismissing and refiling to restart the §1659(a) clock; the court therefore denied the statutory stay argument on those grounds and instead granted a Landis stay.
- The case was administratively closed (not dismissed) pending final ITC resolution; parties must notify the court and propose a case-management plan within 14 days of the ITC’s final resolution.
Issues
| Issue | Plaintiff's Argument | Defendant's Argument | Held |
|---|---|---|---|
| Whether a mandatory §1659(a) stay applies | Ascendis: timely filed stay within 30 days of filing the instant action, so mandatory stay required | BioMarin: Ascendis’s prior suit and dismissal make the stay untimely; cannot restart the §1659 clock by refiling | Court: statutory stay not appropriate given Ascendis’s gamesmanship; will not permit refiling to restart the clock |
| Whether a discretionary stay under Landis is warranted | Ascendis: seeks a stay to avoid parallel forum litigation | BioMarin: requests a Landis stay to avoid parallel litigation and to prevent gamesmanship | Court: grants a Landis stay; factors (harm, hardship, orderly course of justice) favor staying pending ITC |
| Whether proceeding in parallel with the ITC is appropriate | Ascendis: stay avoids duplicative proceedings and follows §1659’s purpose | BioMarin: opposing statutory stay but supports Landis stay; both agree on staying the district action | Court: agrees that parallel proceedings should be avoided; stay appropriate |
| Remedy and case status while ITC pending | Ascendis: administrative closure until ITC resolves | BioMarin: agrees to closure; seeks notice requirement | Court: administratively closes case (not dismissed); parties must file joint notice and case plan within 14 days of ITC finality |
Key Cases Cited
- Landis v. North American Co., 299 U.S. 248 (1936) (recognizes district court’s inherent power to stay proceedings to manage its docket)
- CMAX, Inc. v. Hall, 300 F.2d 265 (9th Cir. 1962) (identifies factors courts weigh when considering a stay)
- Lockyer v. Mirant Corp., 398 F.3d 1098 (9th Cir. 2005) (articulates stay-analysis framework quoting CMAX factors)
- In re Princo Corp., 486 F.3d 1365 (Fed. Cir. 2007) (explains §1659(a) purpose to avoid simultaneous infringement proceedings in two forums)
- Aliphcom v. Fitbit, Inc., 154 F. Supp. 3d 933 (N.D. Cal. 2015) (describes §1659(a) stay as mandatory when timely requested)