Nonstatutory double patenting does not invalidate any patent term extension (PTE) granted under 35 U.S.C. 156, if the claims are otherwise valid under its pre-PTE expiration date. See Novartis AG v. Ezra Ventures LLC, 909 F.3d 1367, 128 USPQ2d 1752 (Fed. Cir. 2018). “For example, if a patent, under its original expiration date without a PTE, should have been (but was not) terminally disclaimed because of obviousness-type double patenting, then this court’s obviousness-type double patenting case law would apply, and the patent could be invalidated. However, if a patent, under its pre-PTE expiration date, is valid under all other provisions of law, then it is entitled to the full term of its PTE.” Id. at 1374, 128 USPQ2d at 1757. The Novartis court upheld the validity of a PTE even when the PTE created potential nonstatutory double patenting issue due to the later date of enforceability of applicable claims of the patent resulting from the PTE finding that the earlier-expired, patentably indistinct patent was “not a double patenting reference” to extended patent. Id. at 1375, 128 USPQ2d at 1757. Specifically, the court held “[b]y applying statutory construction principles, following this court’s precedent in [Merck & Co. v. Hi-Tech Pharmacal Co., 482 F.3d 1317, 82 USPQ2d 1203 (Fed. Cir. 2007)], and addressing traditional obviousness-type double patenting principles, we hold that a PTE pursuant to § 156 is valid so long as the extended patent is otherwise valid without the extension.” Id. Thus, the court declined to allow “a judge-made doctrine” regarding double patenting to “cut off a statutorily-authorized time extension.” Id. at 1375, 128 USPQ2d at 1757.