Added Matter

Patent jargon related to priority and validity. A patent’s claims must be based on the disclosure filed in the patent office and the date of that disclosure establishes the patentee’s right to the claimed invention. Added matter is new information added to the patent claim after the asserted priority date, on which one or more claims are based. Article 123(2) of the European Patent Convention provides that

“A European patent application or a European patent may not be amended in such a way that it contains subject-matter which extends beyond the content of the application as filed.”

Although in most EPC countries a patent holder can amend the claims of a patent to remove added matter and thus remove an added matter objection, a failure to do before seeking to enforce the patent may mean that it will be invalidated in court. At the same time, amending patent claims to remove added matter may make the claims broader – but post grant broadening is impermissible in Europe; leading to the patentee being unable to maintain the patent in its current form because of added matter, and being unable to remove that added matter because doing so would broaden the scope of protection.

In the US context added matter is more likely to be seen either as:

(a) an amending disclosure, giving rise to a Continuation-in-Part (CIP) with a second priority date for the new material; or

(b) a claim that is not supported by the disclosure of the patent, which is invalid.

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