Third Circuit Reminds Litigators: An Unfinished Discovery Order Is Not Final and Thus Not Appealable

In a precedential opinion issued this year, In re Amgen Inc. for Assistance Before A Foreign Tribunal Celltrion USA, Inc., 139 F.4th 265 (3d Cir. 2025) the U.S. Court of Appeals for the Third Circuit issued an important reminder for litigators across the country that a discovery order that leaves open questions about what must actually be produced is not “final” and cannot yet be appealed.

While the decision arose in the niche context of a foreign discovery request under 28 U.S.C. § 1782, its reasoning applies more broadly to any situation where a federal court resolves a discovery dispute but stops short of fully defining the parties’ or nonparties’ obligations.

The Case: Amgen v. Celltrion

The underlying case involves a patent fight in South Korea, where biotechnology company Amgen is suing Celltrion Korea. In support of its foreign litigation, Amgen sought to compel discovery from Celltrion’s U.S. subsidiary in New Jersey. Pursuant to § 1782, Amgen requested 82 categories of documents and testimony.

Celltrion USA opposed the request, arguing it was improper and overbroad. The magistrate judge ruled in favor of Amgen and allowed the discovery request to proceed, but left the exact scope of production to be worked out at a future date, directing the parties to meet and confer and craft a confidentiality order. The district court affirmed.

Celltrion USA then appealed to the Third Circuit, arguing that in a § 1782 proceeding, where discovery is the whole point, such an order should be treated as final.

The Holding

The Third Circuit disagreed with Celltrion USA and dismissed the appeal.

The court reiterated the final judgment rule that an order is final and appealable under 28 U.S.C. § 1291 only if it resolves all substantive issues before the trial court and leaves nothing else to decide. If the order “remains open, unfinished or inconclusive,” it cannot be appealed.

Here, the magistrate judge’s order left open significant issues about what Celltrion USA was actually obligated to produce. That unresolved scope meant, in the view of the Third Circuit, that the order was not truly final and thus unappealable.

The court stressed that letting appeals go forward before the scope of discovery is ascertained would violate the finality principle and encourage piecemeal litigation.

Broader Lessons for Litigators

Although the Amgen case arose under the relatively obscure § 1782, the Third Circuit’s reasoning is not limited to that context. The decision offers valuable guidance for ancillary and satellite discovery proceedings more generally, which litigants much more frequently encounter.

For example, in a typical civil case filed in one district (for instance, New York), parties often serve subpoenas on nonparties in another district (for instance, New Jersey). Disputes over those subpoenas are resolved in the local district court under Rules 37 and 45. Those proceedings are separate from the main case, and once the local judge resolves the discovery dispute, either by compelling, limiting, or quashing the subpoena, the losing party may want to appeal.

But Amgen v. Celltrion holds that an appeal cannot proceed until the lower court has fully and conclusively defined the obligations of the nonparty. If the order leaves open the scope of discovery or invites further negotiation, it is not yet final, and therefore not yet appealable.

Takeaways for Practice

Before filing an appeal from a discovery order even in a standalone or ancillary proceeding, litigators would be wise to confirm that the trial court has fully resolved the dispute. If the order leaves the scope or terms to be determined later, the appellate court will likely dismiss the appeal for lack of jurisdiction. Litigators should seek the entry of a clear and conclusive order so that appellate review (if necessary) can proceed.

The final-judgment rule is a bedrock of federal procedure, designed to avoid piecemeal litigation and conserve judicial resources. Amgen v. Celltrion is a timely reminder that this rule applies just as much in satellite discovery disputes as it does in traditional litigation.

Litigators handling out-of-district subpoenas, nonparty discovery fights, or other ancillary matters would be wise to make sure the order being challenged fully resolves the issue before an appeal is filed. Otherwise, litigators risk wasting time and client resources on an appeal the court will not even entertain.

If you have any questions about the information in this post or if you would like to learn more on this topic you can contact Brendon at bogrady@hoaglandlongo.com or 732-545-4717.