In IPR2012-00022, the Patent Trial and Appeals Board ("PTAB") (A.P.J.s Tierney, Green and Robertson) issued an order in Ariosa Diagnostics ("Petitioner") v. Isis Innovation Limited ("Patent Owner") regarding Ariosa's standing. Section 315 specifies that "[a]n inter partes review may not be instituted if, before the date on which the petition for such review is filed, the petitioner or real party in interest filed a civil action challenging the validity of a claim of the patent." Notably, however, Section 315 exempts the filing of a counterclaim challenging the validity of a claim of a patent from the definition of a "civil action." 35 U.S.C. § 315 (a)(3). The issue presented here is whether raising the defense of invalidity in an affirmative defense falls with the definition of a "civil action" under Section 315.

Ariosa filed a civil action against the exclusive licensee of U.S. Patent No. 6,258,540 seeking a declaration that it did not infringe any claim of the '540 Patent. In the declaratory judgment action, the exclusive licensee counterclaimed for infringement. In response, Ariosa answered by raising the affirmative defense of invalidity of the '540 patent. According to Isis, the fact that Ariosa challenged the validity of the '540 patent claims in an affirmative answer rather than a complaint "is of no moment." Isis argued that section 315(a)(3) exemption is limited to a counterclaim and does not include affirmative defenses. Thus, the Board was presented with the issue of whether the Section 315 deprives a party of standing when that party raise the defense of invalidity in its answer in response to a counterclaim of infringment.

The Board relied on the definition of "civil action" set forth in the Federal Rules of Civil Procedure and held that it refers to the filing of a complaint to "commence" a civil action:

Rule 2 of the Federal Rules of Civil Procedure1 states that "[t]here is one form of action--the civil action," and Rule 3 states that "[a] civil action is commenced by filing a complaint with court." Defenses are raised in answer to the complaint or in answer to a counterclaim. Fed. R. Civ. P. 12. We thus conclude that when the statute refers to filing a civil action, it refers to filing a complaint with the court to commence the civil action. See, e.g., Baldwin Cnty Welcome Ctr v. Brown, 466 U.S. 147, 149 (1984) (citing Fed. R. Civ. P. 3 for the proposition that a civil action is brought upon the filing of a complaint with the court).

Relying on Cardinal Chem. Co. v. Morton Int'l, Inc., 508 U.S. 83 (1193), the Board held that an affirmative defense of invalidity cannot be considered a filing of a civil action for invalidity.

Thus, it is clear from Cardinal Chem. Co. that there is a fundamental difference between an affirmative defense of invalidity and a counterclaim of invalidity. The affirmative defense of invalidity is tied to the claim of infringement, whereas a counterclaim of invalidity is independent from the claim of infringement, which survives a finding of noninfringement. Section 315(a)(3) makes clear that if a party is faced with a claim of infringement, it can bring the independent claim of invalidity as a counterclaim and still avail itself of inter partes review.

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As discussed supra, the statute clearly defines which civil actions, when filed, bar a party from filing an inter partes review--civil actions challenging the validity of a patent. A civil action for a declaratory judgment of non-infringement is not a civil action challenging the validity of a patent. Moreover, as discussed above, asserting an affirmative defense of invalidity is treated differently than a counterclaim for invalidity, and thus for the purposes of 315(a)(1) cannot be considered a filing of a civil action for invalidity. And as also discussed above, that interpretation of section 315(a)(1) does not conflict with the explicit exclusion in 315(a)(3) of filing a counterclaim for invalidity.

The Board thus concluded that the petitioner Isis was not barred from filing a petition for inter partes review of the '540 patent by virtue of filing an affirmative answer of invalidity in response to a counterclaim of infringement.

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This decision clarifies that the application of Section 315 does not deprive a petitioner from seeking inter partes review of a patent even if the petitioner asserted an affirmative defense of invalidity in response to a counterclaim of infringement. Ariosa Diagnostics v. Isis Innovation Limited , Case IPR2012-00022 (J. Green) (February 12, 2013), Paper 20.