What Litigators Can Teach the Patent Office About Pharmaceutical Patents

59 Pages Posted: 11 Aug 2021 Last revised: 5 Aug 2022

See all articles by S. Sean Tu

S. Sean Tu

West Virginia University College of Law; Program On Regulation, Therapeutics, And Law (PORTAL), Brigham and Women's Hospital; Georgetown University - The O'Neill Institute for National and Global Health Law

Mark A. Lemley

Stanford Law School

Date Written: August 11, 2021


Pharmaceutical patents listed in the FDA’s “Orange Book” are some of the most valuable patents in the world. Accordingly, for this valuable subset of patents, it is paramount that the Patent & Trademark Office (PTO) correctly issue valid patents and preclude invalid patents from issuing.

In this paper, we study what happens to those patents in litigation, reporting the results for every Orange Book patent case that resulted in a merits decision. We find that about 25% of active Orange Book patents were invalidated in court. Since these invalid patents could wrongly increase the costs of prescription drugs, we investigate what happens during prosecution of these patents at the PTO. Our study is the first to link the prosecution of Orange Book patents directly to litigation outcomes. Our goal is to determine if there are ways to identify and prevent the issuance of these later invalidated Orange Book patents.

We find that litigated Orange Book patents have unique characteristics that distinguish them from other pharmaceutical patents. They are issued by a relatively small number of examiners. Most litigated patents (90%) are “secondary” patents – patents on smaller tweaks to an existing drug rather than a patent on a new chemical. The owners of these later-litigated patent applications treat them very differently than they do other patents in the same field. They are part of large patent families, suggesting that the applicants are trying to build a patent fence around a known product. They frequently employ a procedural device known as “Track One” to obtain quicker patent prosecution. They are more likely to be subject to rejections based on double-patenting. When initially rejected by the patent examiner, owners of these applications are more likely to fight back rather than amend their claims. All of this suggests that applicants enter prosecution with these patents knowing that they are important and likely destined for litigation, and that they are deliberately creating patent “thickets” to make it harder for generics to enter the market.

Remarkably, we find that while patent examiners already have more time to spend on Orange Book patents than on other patents, the prosecution history of many of these invalidated patents are identical. That is, many of these invalidated patents have the same assignee, the same examiner and the same prosecuting attorney cut and paste rejections as well as responses, thus creating identical or very similar prosecution histories.

We also find that while the patents that end up being litigated are clearly distinguishable from other pharmaceutical patents during patent prosecution, there is little difference in the PTO between the patents that end up surviving a court challenge and the ones that are invalidated.

Our data offer important guidance for reforming the process of prosecuting Orange Book patents. We can and should take advantage of advance knowledge about the importance of these patents to give them a more thorough examination early on. At the same time, the experience with cut-and-paste rejections suggests that we cannot simply give examiners more time and hope that they will do a more thorough job. That not only helps inform the policy suggestions we offer, but it sheds light on a long-standing academic debate about how much time and money we should spend examining patents.

Further, our data highlight the importance of secondary patents and patent thickets in Orange Book litigation. We offer a number of suggestions to simplify and streamline patent prosecution and litigation to make it harder to exclude generic entry with a thicket of bad patents.

Suggested Citation

Tu, Shine (Sean) and Lemley, Mark A., What Litigators Can Teach the Patent Office About Pharmaceutical Patents (August 11, 2021). WVU College of Law Research Paper No. 2021-015, Washington Law Review, Vol. 99, No. 1673, 2022, Available at SSRN: https://ssrn.com/abstract=3903513 or http://dx.doi.org/10.2139/ssrn.3903513

Shine (Sean) Tu

West Virginia University College of Law ( email )

101 Law School Drive
Morgantown, WV West Virginia 26506
United States

HOME PAGE: http://https://www.law.wvu.edu/faculty-staff/faculty/s-sean-tu

Program On Regulation, Therapeutics, And Law (PORTAL), Brigham and Women's Hospital ( email )

1620 Tremont St.
Suite 3012
Boston, MA 02120
United States

HOME PAGE: http://https://www.portalresearch.org/sean-tu.html

Georgetown University - The O'Neill Institute for National and Global Health Law ( email )

600 New Jersey Avenue, NW
Washington, DC 20001
United States

HOME PAGE: http://https://oneill.law.georgetown.edu/experts/s-sean-tu/

Mark A. Lemley (Contact Author)

Stanford Law School ( email )

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

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