Composition of Matter vs. Method of Treatment Claims | Wysebridge

A composition-of-matter claim protects a chemical compound, molecule, formulation, or other qualifying composition itself — regardless of how it is used. A method-of-treatment claim protects a specific therapeutic use of a substance, reciting the act of administering it to treat a defined condition. The same drug can be covered by both: a composition claim on the compound itself, and separate method claims on particular diseases, dosages, or patient populations it is used to treat.

Composition-of-Matter vs. Method-of-Treatment Claims

Claim Examples

Composition-of-matter claim:

"1. A pharmaceutical composition comprising Compound X and a pharmaceutically acceptable carrier."

This claim covers Compound X in that formulation no matter what disease it is later used to treat.

Method-of-treatment claim:

"1. A method of treating rheumatoid arthritis in a patient, comprising administering an effective amount of Compound X to the patient."

This claim covers only the act of using Compound X for that specific treatment — it does not give the claim holder rights over Compound X itself if someone else already controls composition rights to it.

Can the Same Drug Have Both Types of Claims?

Yes, and pharmaceutical portfolios routinely do. A composition claim can cover the active compound broadly, while separate method-of-treatment claims cover individual diseases, dosage regimens, patient populations, or combination therapies. This layering is also how companies extend protection on a drug after the original composition patent expires — by patenting new, nonobvious treatment uses discovered later.

Which Is Broader?

A valid composition claim is often commercially broader, because it can cover the compound regardless of the particular disease it is eventually used to treat. But "broader" depends entirely on the limitations actually recited — a narrowly drafted composition claim (e.g., a specific salt form or formulation) can be narrower in practice than a well-drafted method claim covering multiple related indications.

Can an Old Compound Get a New Method-of-Treatment Patent?

Yes. Even if a compound's composition claim has expired or was never patentable because the compound was already known, a new and nonobvious therapeutic use — a new indication, dosing regimen, patient population, or combination — can still support a method-of-treatment patent. This is a common strategy for extending pharmaceutical exclusivity and for repurposing existing drugs ("drug repositioning").

Patent Bar Relevance

35 U.S.C. § 101 lists "process," "machine," "manufacture," and "composition of matter" as the four statutory categories of patentable subject matter. The patent bar exam tests whether a candidate can correctly classify a claim into one of these categories and recognize related eligibility issues — particularly whether a method-of-treatment claim recites a concrete, active treatment step (patent-eligible) versus merely observing or correlating a natural phenomenon (not patent-eligible on its own).