Supernus Pharmaceuticals, Inc. v. Iancu, 913 F.3d 1351

Supernus (owner) and United Therapeutics (exclusive licensee/applicant) prosecuted U.S. application No. 11/412,100 (issued as U.S. Patent No. 8,747,897) after filing an RCE on Feb. 22, 2011; the patent issued June 10, 2014.
The USPTO calculated a Patent Term Adjustment (PTA) of 1,260 days after attributing 2,321 days of USPTO delay and deducting 886 days for applicant delay; 646 of those applicant-delay days were charged for the period from the RCE filing to a later IDS submission (Feb. 22, 2011 to Nov. 29, 2012).
Supernus received notice from European counsel regarding a Sandoz opposition to a European counterpart on Aug. 21, 2012 and filed a supplemental IDS with the USPTO on Nov. 29, 2012 (100 days after the EPO notice; 646 days after the RCE).
The USPTO applied 37 C.F.R. § 1.704(c)(8) to reduce PTA for the entire 646-day interval, reasoning that post‑RCE IDS filings can ‘‘interfere’’ with examination even if substantive information arose later.
The district court granted summary judgment for the USPTO relying on this court’s decision in Gilead; Supernus appealed.
The Federal Circuit reversed, holding that the PTA statute unambiguously forbids charging applicant delay for periods during which the applicant could not have taken steps to conclude prosecution.

Issue	Supernus' Argument	USPTO's Argument	Held
Whether the USPTO may reduce PTA by time periods when the applicant could not have acted to conclude prosecution (i.e., reduction may exceed the period "during which the applicant failed to engage in reasonable efforts").	PTA reductions must equal only the actual period when the applicant failed to engage in reasonable efforts; Supernus could not have acted during the earlier 546 days, so those days cannot be charged.	Regulations (37 C.F.R. §1.704(c)(8)) reasonably allow treating post‑reply supplemental submissions (including post‑RCE IDS) as applicant delay because they potentially force re‑examination.	Reversed USPTO: statute is plain — PTA may only be reduced by a period equal to the time the applicant failed to engage in reasonable efforts; the USPTO cannot include days when no action by the applicant was possible.

Gilead Sciences, Inc. v. Lee, 778 F.3d 1341 (Fed. Cir.) (upholding §1.704(c)(8) as reasonable to treat potential delay as chargeable applicant conduct)
Chevron U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (explaining two‑step framework for agency statutory interpretation)
SAS Institute Inc. v. Iancu, 138 S. Ct. 1348 (statutory language controls where plain)
Pereira v. Sessions, 138 S. Ct. 2105 (court may enforce plain statutory meaning)
City of Arlington v. FCC, 569 U.S. 290 (deference principles and limits on agency authority)
Wyeth v. Kappos, 591 F.3d 1364 (no deference to agency interpretations that conflict with plain statutory text)