OPINION *

Cabot Oil & Gas Corporation (“Cabot Oil”) appeals from the entry of summary judgment in favor of Wayne Harrison and Mary Harrison on its counterclaim. We will affirm.

After briefing was completed in this appeal, we petitioned for certification of the following question to the Supreme Court of Pennsylvania: “When an oil and gas lessor files an unsuccessful lawsuit to invalidate a lease, is the lessee entitled to an equitable *129 extension of the primary lease term equal to the length of time the lawsuit was pending?” Harrison v. Cabot Oil & Gas Corp., No. 12-3613, at 7 (3d Cir. Apr. 7, 2014). That Court granted our petition and issued a thorough and thoughtful opinion on February 17, 2015. In answering our question, the Pennsylvania Supreme Court declared, “We do not foreclose that equitable relief may be available to oil-and-gas-producing companies — subject to applicable requirements governing recourse to equity — where there is an affirmative repudiation of a lease.” Harrison v. Cabot Oil & Gas Corp., — Pa. -, 110 A.3d 178, 186 (2015). But, the Court continued, “the mere pursuit of declaratory relief challenging the validity of a lease does not amount to such.” Id. It explained that it “has required more than the mere assertion of a challenge to the validity of an agreement to demonstrate such repudiation. Under Pennsylvania law, anticipatory repudiation or breach requires an ‘absolute and unequivocal refusal to perform or a distinct and positive statement of an inability to do so.’ ” Id. at 184 (quoting 2401 Pa. Ave. Corp. v. Fed’n of Jewish Agencies of Greater Phila., 507 Pa. 166, 489 A.2d 733, 736 (1985)).

The Pennsylvania Supreme Court’s opinion effectively resolves the sole issue on appeal. Cabot Oil’s counterclaim sought equitable relief based on the request in the Harrisons’ amended complaint for a declaration that the lease was invalid. 1 Because “the mere pursuit of declaratory relief challenging the validity of a lease does not amount to [repudiation],” id. at 186, the District Court properly granted summary judgment against Cabot Oil on its counterclaim.

Cabot Oil acknowledges that, in light of the Pennsylvania Supreme Court’s decision, it cannot prevail on a theory of repudiation. But it argues that its counterclaim is also based on a number of other equitable theories, including estoppel, unjust enrichment, and avoidance of contractual forfeiture. Because the Commonwealth’s Supreme Court did not address those alternative theories, Cabot Oil urges us to do so now.

Contrary to Cabot Oil’s assertion, however, its counterclaim was based solely, and explicitly, on a theory of repudiation. In its briefing before us, Cabot Oil did briefly discuss alternative theories that other jurisdictions have used to justify the equitable relief it seeks, but its briefing focuses, appropriately, on the one theory actually alleged in its counterclaim: repudiation. Other theories of relief are therefore not properly before us. See Josey v. John R. Hollingsworth Corp., 996 F.2d 632, 641-42 (3d Cir. 1993) (treating as forfeited a claim that was neither raised in complaint nor added by amendment). Accordingly, we will affirm the order of the District Court.