Question 1

What should I do first when I get a patent cease-and-desist letter?

Accepted Answer

Forward the letter to leadership, preserve every related document and message, and within 24-48 hours get a 1-hour triage call with a patent litigator. Do not respond substantively, do not delete anything, and do not assume the threat is empty just because the patent is unfamiliar.

Question 2

How serious is a single-patent cease-and-desist letter?

Accepted Answer

Severity depends on four signals: how many patents are asserted (one is far less dangerous than a portfolio), whether you actually practice the asserted claims, how much time you have before the stated deadline, and your revenue (which drives settlement economics). A single-patent letter over an obscure product with a 30-day window is often manageable; a pre-suit notice with a 10-day window over a product you obviously sell is urgent.

Question 3

What are the main defenses to a patent assertion?

Accepted Answer

The five most common defenses are: non-infringement (your product does not meet every claim element, the all-elements rule), invalidity (the claims are anticipated or obvious over prior art), file-history estoppel (statements the patent owner made during prosecution narrow the claims), unenforceability (the patent was procured by fraud on the USPTO), and §101 ineligibility (the claims are drawn to abstract ideas under Alice/Mayo). A good litigator checks all of them in parallel.

Question 4

How much does it cost to defend a patent assertion?

Accepted Answer

A first response and claim-chart review typically costs $3,000-$8,000. A license negotiation runs $10,000-$50,000. Defending through the PTAB (inter partes review) or a district court typically runs $30,000-$250,000+ depending on revenue at risk, the number of asserted patents, and whether you settle. The earlier you triage, the less expensive every later path is.

Question 5

Should I ignore a cease-and-desist letter?

Accepted Answer

Almost never. Ignoring a credible assertion can support a default judgment, an injunction, and enhanced damages including willful infringement (up to triple). Even when the patent is weak, a thoughtful response preserves your defenses and may deter suit. The only safe time to ignore is when the letter is facially invalid (wrong party, expired patent, claims not covering your product) and your litigator concurs.

You got a patent letter. Now what?