Brief of Patent Law Professors as Amici Curiae in Support of Petitioners (Apple Inc. et al. v. California Institute of Technology)

18 Pages Posted: 10 Oct 2022

See all articles by Christa Laser

Christa Laser

Cleveland-Marshall College of Law

Mark A. Lemley

Stanford Law School

Date Written: October 6, 2022


Amici are law professors with an interest in patent law and patent administrative procedure. The Supreme Court should reverse the Federal Circuit and hold that estoppel following inter partes review (IPR) extends only to grounds that a party “raised or reasonably could have raised during that inter partes review,” with “during that inter partes review” meaning the time period between institution and final decision, as indicated by the statutory text. Specifically, the statute delineates the process of deciding whether to “institute” review from the “proceeding” where the Board will “conduct” the “review.” The statute notes the date “on which the review shall commence” and says that the “length of review” is the “time between the institution . . . and . . . final written decision.”

A broad reading of the estoppel provision also raises questions of procedural fairness in light of the Board’s practices. By regulation, the Patent Office imposes strict page limits on petitions, such that petitioners cannot raise all potential grounds for invalidity. Then, in future proceedings, the petitioner might face a billion-dollar infringement verdict on a patent where legitimate grounds for invalidity are barred from consideration despite never being decided before. A broad reading also complicates future proceedings by requiring a determination of what prior art a petitioner should have known about at the time of its petition. This is an important issue; innovation markets cannot function efficiently with uncertainty on whether a party facing a patent infringement lawsuit is barred from defending against it on grounds of invalidity of the patent.

Keywords: supreme court, brief, amicus, amici, amicus brief, supreme court brief, certiorari, patents, estoppel, ipr, inter partes review, ipr estoppel, statutory estoppel, federal circuit, prior art

Suggested Citation

Laser, Christa and Lemley, Mark A., Brief of Patent Law Professors as Amici Curiae in Support of Petitioners (Apple Inc. et al. v. California Institute of Technology) (October 6, 2022). Available at SSRN: or

Christa Laser (Contact Author)

Cleveland-Marshall College of Law ( email )

2121 Euclid Avenue, LB 138
Cleveland, OH 44115-2214
United States

Mark A. Lemley

Stanford Law School ( email )

559 Nathan Abbott Way
Stanford, CA 94305-8610
United States

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