Questions of novelty in medical use patents
When a substance with a diagnostic or therapeutic effect per se has been available in the prior art, it will become more important to effectively protect the medical use of the substance, particularly in a jurisdiction (such as China) where diagnostic or therapeutic methods are not patent-eligible.
Medical use inventions may be drafted in the format of Swiss-type use claims. Specifically, if an invention involves the discovery of the therapeutic use of substance X, or treatment of a certain new disease using X, a medical use claim may be drafted in a format such as “use of substance X for the manufacture of a medicament” or “use of substance X for the manufacture of a medicament for treating a disease”.
Even though the “substance” and “disease” are essential in such a claim, there may be additional features therein, including a new dosage regimen such as a new mode, route, usage amount and interval of administration, and subject to be treated. It has been long debated whether these features would make a claimed technical solution patentable if both the “substance” and “disease” are known in the art. Some recent cases have illustrated these issues.
Case study
The most influential case was ruled on by the Supreme People’s Court in 2013. The independent claim 1 of the patent-in-suit is directed to the use of daptomycin for the manufacture of a medicament for treating a bacterial infection in a patient without resulting in skeletal muscle toxicity, where a dose for the treatment is 3 to 75 mg/kg of daptomycin once every 24 hours to 48 hours. Features of administration dose and administration interval are included in the claim.
The Supreme People’s Court held that “this kind of (Swiss-type) claim binds the making behaviour of a manufacturer who makes a drug for a certain use, so the technical features of the claims should be analysed from the perspective of process claims”.
It added: “As for the features only relating to how to use a medicament, such as administration dose, administration interval and the like, if these technical features are not directly related to the procedure of manufacture of the medicament, they substantially belong to specific courses of administering the medicament to the human body after the procedure of manufacture of the medicament has been carried out and the medicament has been obtained, and are not directly and necessarily associated with the procedure of manufacture of medicament.
“These technical features merely present in the course of administration are not technical features in the procedure of manufacture of medicament, and do not have any limiting effect on the procedure of manufacture of medicament per se.”
More case law
In May 2018, the Patent Reexamination Board (PRB) made an invalidation decision to further illustrate how the subject to be treated may influence the novelty of a second medical use claim.
The patent-in-suit is directed to the medical use of an antibody. Specifically, independent claim 1 in the patent reads “use of an anti-CD20 antibody in the preparation of a medicament for the treatment of relapsed B-cell lymphoma in a human patient, wherein the patient has relapsed following treatment with an anti-CD20 antibody”.
