[35 U.S.C. §] 24 only empowers a district court to issue a subpoena for use in a "contested case," [which] are limited to those in which the [PTO regulations] authorize the parties to take depositions and do not include] inter partes reexamination proceedings.

On March 20, 2013, in Abbott Labs. v. Cordis Corp., the U.S. Court of Appeals for the Federal Circuit (Rader, Dyk,* Reyna) affirmed the district court's grant of Abbott's motion to quash two subpoenas duces tecum issued pursuant to 35 U.S.C. § 24 in a case where Cordis alleged that Abbott infringed U.S. Patents No. 6,746,773 and No. 7,591,844, which related to drug-eluting stents. The Federal Circuit stated:

Section 24 of title 35 of the U.S. Code provides that "[t]he clerk of any United States court for the district wherein testimony is to be taken for use in any contested case in the Patent and Trademark Office, shall, upon the application of any party thereto, issue a subpoena for any witness residing or being within such district, commanding him to appear and testify." . . . The question of whether 35 U.S.C. § 24 empowers a district court to issue a subpoena for use in an inter partes reexamination turns on whether an inter partes reexamination is a "contested case" within the meaning of section 24. The proper interpretation of section 24 is a question of first impression in this court. We construe the term "contested case," as used in section 24, as referring to a proceeding in which the PTO has provided for the taking of depositions for use in that proceeding. . . . We do not find the parties' dueling laundry lists of the attributes of a "contested case" to be useful in determining the meaning of section 24. Instead, we construe the provision in light of its plain text and relationship with adjacent provisions of title 35, its legislative history, and the interpretation given to it by other courts. . . .

The relationship between section 24 and the immediately preceding section of title 35 shows that Congress has entrusted to the PTO the power to decide by regulation which proceedings require "testimony . . . to be taken for use." Section 23 of title 35 allows the Director of the PTO to "establish rules for taking . . . depositions required in cases in the [PTO]," and allows "[a]ny officer authorized by law to take depositions to be used in [state or federal courts to] take such . . . depositions." . . . The legislative history of section 24 also supports this reading. Sections 23 and 24 were enacted in 1861 to help the PTO secure needed testimony from recalcitrant fact witnesses. In the years before the enactment of these provisions, the PTO's rules allowed depositions to be taken in interferences and patent term extension proceedings, but offered no means for compelling the attendance of deponents. . . .

Congress's most recent amendment to the Patent Act further demonstrates that Congress intended for subpoenas under section 24 to be made available in those proceedings in which depositions are relied upon by the PTO. In 2011, Congress replaced inter partes reexamination with a new proceeding called inter partes review. The purpose of this reform was to "convert[] inter partes reexamination from an examinational to an adjudicative proceeding," and one of its touted "improvements" over the former proceeding is to allow the limited use of depositions. In particular, Congress provided for depositions of affiants in the proceeding, and also authorized parties to "seek such discovery as the Patent Office determines is otherwise necessary in the interest of justice." In the course of implementing these mandates, the PTO has recognized that the AIA authorizes parties to seek section 24 subpoenas in the new proceedings. Congress's actions in creating these inter partes review proceedings thus demonstrate that depositions and section 24 subpoenas go hand in hand. . . .

The PTO regulations make no provision for the taking of depositions in proceedings before examiners. Depositions are allowed only in matters before the Board. The PTO's regulations for inter partes reexaminations make no provision for either party to take depositions. The PTO's regulations indeed specifically exclude appeals of inter partes reexaminations (the only stage of the reexamination occurring before the Board) from the category of Board proceedings in which depositions are allowed by defining such proceedings as not being "contested cases." The PTO also has stated that "[t]he existence of a contested case [within the meaning of 37 C.F.R. § 41.2] is a predicate for authorizing a subpoena under 35 U.S.C.[ §] 24." The only PTO regulations providing for depositions in patent proceedings apply exclusively to interferences, derivation proceedings, and the new Board proceedings created by the AIA. Each of these regulations, moreover, is accompanied by a regulation explicitly allowing the parties to seek section 24 subpoenas in the covered proceedings, reinforcing the connection between the availability of depositions and compelled production. . . . The PTO's regulations thus do not permit parties to take depositions in inter partes reexaminations, and section 24 subpoenas are not available in such proceedings.