You Received a Patent Cease-and-Desist Letter. Now What?
The letter usually arrives on law-firm letterhead. It names a patent, claims your product infringes it, and demands that you stop selling, sometimes with a royalty demand and a deadline attached. If you are reading this shortly after opening one, here is what that letter actually means and what to do about it, in order.
First: do not ignore it, and do not fire back
A cease-and-desist letter is not a lawsuit. Nobody has sued you yet, and in many cases nobody ever will. But ignoring the letter is a mistake with a price: from the day you know about the patent, continued infringement can be found willful, and willful infringement can multiply damages if a suit comes later. Silence also tells the sender you have no defense prepared.
Firing back is the other mistake. An angry reply, a phone call to the sender, or a public post about the dispute can create admissions you cannot take back. In some circumstances a response can hand the patent owner exactly what it needs to pick the time and place of a lawsuit. Say nothing of substance to the other side until someone qualified has looked at the patent.
In the meantime, preserve everything: the letter, the envelope, your product documentation, and your records of when you began developing and selling what you sell. Dates matter enormously in patent disputes.
Second: find out what the letter actually asserts
Read the letter carefully and pull out four things: the patent number(s), the specific claims asserted (many letters never say), the products accused, and any deadline. Then the real work starts, because a demand letter rests on a chain of assumptions, and every link can be tested:
Is the patent in force? Patents expire, and they lapse early when maintenance fees go unpaid. This check takes minutes and occasionally ends the matter on the spot.
Do the claims actually cover your product? Infringement is measured against the patent's claims, element by element, not against its title, its drawings, or the sender's characterization. It is common for an accused product to be missing an element that every asserted claim requires.
Is the patent valid? This is the question demand letters hope you never ask. The examiner who allowed the patent saw only the prior art that was found at the time. If earlier patents or publications describe the same invention, the claims should never have been granted. There is a formal, affordable way to put that art in front of the USPTO.
Third: know your options
Depending on what that review shows, the realistic paths are: change the product so it clearly avoids the claims (a design-around); negotiate a license, from a position of knowledge rather than fear; respond with a non-infringement position; or challenge the patent's validity itself. If you have actually been sued, not just threatened, you also need litigation counsel, and you need them before any court deadline runs.
The option most people don't know they have: reexamination
Ex parte reexamination asks the USPTO to take a second look at an issued patent in light of prior art the original examiner never saw. Any person may request it. Claims that do not survive are canceled, and a canceled claim cannot be asserted against you or anyone else. Claims the owner has to narrow to survive may no longer cover your product at all. The request can be filed without identifying who asked for it, and the whole proceeding costs a small fraction of defending a lawsuit.
This is work we know from both sides. Our practitioners have spent seventeen years getting claims allowed at the USPTO, which is an education in exactly where allowed claims are vulnerable, and our search practice regularly uncovers prior art that was never found during the original prosecution. How our reexamination service works →
What to do this week
- Calendar any deadline in the letter, and do not let it pass silently.
- Say nothing of substance to the sender.
- Preserve your records.
- Get the patent, the claims, and your product in front of a registered patent practitioner.
We offer a free, confidential consultation. Send us the patent number and the letter, and we will give you a straight answer about the patent's vulnerabilities and whether reexamination or an invalidity search fits your situation. Contact us.
Disclaimer: This article is provided for general information and does not constitute legal advice or create a client relationship. A cease-and-desist letter can carry deadlines and consequences specific to your circumstances; consult qualified counsel promptly. Underwood & Associates practices exclusively before the USPTO; for litigation matters we work alongside your litigation counsel.