BPCIA Litigation: Patent Dance, Notice of Marketing, and Remedies

BPCIA litigation is the patent dispute process Congress built into the Biologics Price Competition and Innovation Act, codified at 42 U.S.C. § 262(l), that runs between a brand-name biologic sponsor and a biosimilar applicant before the biosimilar can reach patients. It has three moving parts: a mandatory information exchange known as the patent dance, a first-phase federal infringement lawsuit over a curated set of patents, and a second-phase lawsuit triggered by the applicant’s 180-day notice of commercial marketing. Each step runs on statutory deadlines, and the choices made at each step shape the remedies available at the end.

When BPCIA Litigation Can Begin

The statute’s exclusivity provisions decide when any of this can happen. A brand-name biologic receives 12 years of market exclusivity from the date the FDA first licenses it, and no biosimilar application can be submitted until four years after that licensure.¹

Once the four-year bar passes, a biosimilar maker can file a subsection (k) application. FDA acceptance of that application is what starts the patent litigation clock.²

The Patent Dance

The patent dance is the choreographed exchange that identifies which patents the parties will actually litigate. It runs on tight deadlines, and each side’s disclosures narrow the dispute.

Application and Manufacturing Disclosure

Within 20 days of the FDA notifying the applicant that its application has been accepted, the biosimilar maker must give the sponsor a copy of the application and information describing its manufacturing processes. Confidentiality rules restrict who can see it: only designated outside counsel and a single in-house attorney who does not work on patent prosecution for the reference product.¹

Scientists, executives, and other lawyers at the sponsor do not see the confidential material without the applicant’s written consent. The wall exists because the applicant is handing over proprietary manufacturing information that the sponsor could otherwise use for purposes beyond patent enforcement.

Patent Lists and Responses

The sponsor then has 60 days to give the applicant two things: a list of patents it believes the biosimilar could infringe, and an identification of which of those patents it would license.

The applicant has 60 days to respond. For each patent on the list, it must provide a claim-by-claim explanation of why the patent is invalid, unenforceable, or will not be infringed, or state that it will not launch commercially before the patent expires. The applicant can also add patents it thinks the sponsor missed. The sponsor then has 60 more days to rebut, defending validity and explaining why it expects infringement.¹

Selecting Patents for the First Lawsuit

The parties then have 15 days to negotiate which patents go into the first suit. If they cannot agree, the statute takes over. The applicant picks a number of patents it wants litigated and tells the sponsor. Within five days, both sides simultaneously exchange lists, and the sponsor cannot list more patents than the applicant did. If the applicant lists zero, the sponsor gets exactly one.¹

What Happens if the Applicant Skips the Dance

Nothing in the statute forces an applicant to participate. The Supreme Court confirmed this in Sandoz Inc. v. Amgen Inc. (2017), holding that a sponsor cannot obtain a federal injunction to compel the exchange.

Skipping carries consequences. If the applicant refuses to hand over its application and manufacturing information, the sponsor can immediately file a declaratory judgment action and can assert any patent that could have been listed during the exchange, not just a curated set. The applicant loses the right to bring its own declaratory judgment action.¹

Some biosimilar companies accept that trade rather than reveal manufacturing details to a competitor.

First-Phase Infringement Lawsuit

Once patent selection is complete, the sponsor has 30 days to file infringement suits covering each patent on the agreed or exchanged lists.¹

The legal theory is unusual. Ordinary patent law requires that the defendant have made, used, or sold the patented product. A biosimilar applicant has not sold anything yet. A separate federal statute solves this by treating the submission of a biosimilar application referencing a patented biologic as an “artificial act of infringement” sufficient to support the lawsuit.³

Federal district courts hear these cases, generally on accelerated schedules. Most of the work is claim construction: reading the technical language of each patent, deciding what it covers, and comparing that against the biosimilar’s molecular structure and manufacturing process. The applicant wins by showing non-infringement or invalidity.

Safe Harbor During Development

Throughout development, biosimilar makers rely on a research safe harbor: using a patented invention for purposes reasonably related to developing and submitting regulatory information is not infringement.³

Testing, characterization studies, and clinical trials aimed at an FDA application fall within it, and courts have read the protection to cover experiments that never end up in a submission so long as they were reasonably related to generating data for one. The safe harbor does not cover basic research untethered to a specific regulatory product, and it stops applying once the biosimilar is approved and the company begins commercial manufacturing for sale. At that point, unresolved patent claims become live.

Notice of Commercial Marketing

Before launching commercially, the biosimilar applicant must give the sponsor at least 180 days’ notice.¹

When that notice can be given was disputed for years. The Federal Circuit had held that the notice could only come after FDA licensure, which would have added six months to every reference product’s effective exclusivity. The Supreme Court’s 2017 Sandoz decision rejected that reading and allowed the notice to be given before licensure. Most applicants now provide it as early as possible so the 180-day clock runs during FDA review.

Second-Phase Infringement Lawsuit

The 180-day notice opens a second round of litigation. This round covers patents that were listed during the patent dance but not selected for the first case, along with patents that did not exist during the original exchange. The sponsor has 30 days after any new patent issues or is exclusively licensed to supplement its list, and the applicant has 30 days to respond with invalidity or non-infringement positions.¹

The second phase exists because biologics tend to be covered by layered patent families: the molecule itself, manufacturing methods, formulations, and therapeutic uses. New patents keep issuing during the years a biosimilar takes to develop. Without a second round, a sponsor could lose the first case on narrow grounds while other valid patents still block the product.

Injunctions and Damages

The 180-day window largely exists so the sponsor can seek a preliminary injunction blocking launch while disputes are resolved. The statute expressly authorizes this remedy for patents identified during the patent dance but held back from the first-phase suit.¹

To win a preliminary injunction, the sponsor must show likelihood of success on the merits, irreparable harm without the injunction, a favorable balance of hardships, and that the public interest supports blocking the launch. Courts weigh these carefully, particularly given the patient-access stakes when a lower-cost biologic is at issue.

Launching “at risk” before litigation ends carries serious exposure. On a finding of infringement, general patent law allows damages and gives the court discretion to increase them up to three times the amount assessed.⁴ Enhanced damages are typically reserved for willful or egregious infringement, and a company that launched knowing patent claims were unresolved is in exactly the posture where willfulness gets found. After trial, the court can issue a permanent injunction removing the biosimilar from the market, or it can leave the product on the market subject to ongoing royalties. Which remedy applies depends on how the litigation looks by the time of judgment.

The Purple Book and Pre-Filing Visibility

The Consolidated Appropriations Act of 2021 added a transparency layer that affects how BPCIA litigation is set up. Sponsors must submit their patent lists and expiration dates to the FDA for publication in the Purple Book, a public database of licensed biological products.⁵

Initial lists must be submitted within 30 days of sharing them with a biosimilar applicant during the patent dance, and supplements follow the same timeline. The FDA updates the database monthly and publishes what the sponsor submits without evaluating validity, enforceability, or relevance.⁶

The Purple Book does not eliminate uncertainty, because a sponsor can still assert patents not on the list. It does give prospective biosimilar developers a starting map of the patent landscape before they commit the sums needed to build a competing product.

1
Office of the Law Revision Counsel. 42 USC 262 – Regulation of Biological Products
2
U.S. Food and Drug Administration. Biological Product Innovation and Competition
3
Office of the Law Revision Counsel. 35 USC 271 – Infringement of Patent
4
Office of the Law Revision Counsel. 35 USC 284 – Damages
5
U.S. Food and Drug Administration. Purple Book Database of Licensed Biological Products
6
U.S. Food and Drug Administration. Purple Book Database FAQs