TOPICS

“Cytotoxicity-Inducing Therapeutic Agent”

Overview:

This case sought revocation of a JPO trial decision that had dismissed a request for a patent invalidation trial. The court reversed the trial decision.

▶Summary of Judgment and Link to Full Text (Japanese)

Main Issue:

Whether Corrected Invention 1 is taught in Plaintiff’s Exhibit 10, and whether a person skilled in the art could have easily made the invention based on the invention taught in Plaintiff’s Exhibit 10.

Summary:
(1) Novelty

Paragraph 0744 of Plaintiff’s Exhibit 10 merely states that “certain other Fc regions” may be used where it is desirable to eliminate or reduce effector function, and does not make clear what those “certain other Fc regions” specifically are. Even if a D265A mutation in the Fc region was well known or part of common general knowledge as one means of lowering Fcγ receptor binding affinity and reducing effector function, it cannot be said that the specific D265A mutation is described among those “certain other Fc regions,” or described to an equivalent degree.

In contrast, …cited in para. 0142 of Plaintiff’s Exhibit 10 (Plaintiff’s Exhibit 52) states that a D265A substitution severely inhibited C1q binding and reduced complement-dependent cytotoxic activity.

However, while it can be vaguely understood that…(Plaintiff’s Exhibit 52) discloses some mutation(s) in an Fc region having increased or decreased C1q-binding ability, concrete and specific technical matters relating to the D265A mutation inhibiting C1q binding cannot be ascertained without consulting Plaintiff’s Exhibit 52 itself. Therefore, such concrete and specific technical matters that cannot be grasped without checking the cited document itself cannot be regarded as the matters taught in Plaintiff’s Exhibit 10.

Accordingly, Difference 3, as found in the trial decision, is recognized.

…

For the reasons above, … Difference 3 is recognized, and thus Corrected Invention 1 differs from the Exhibit 10 invention at least in Difference 3.

(2) Inventive step

In the bispecific antibody of the Exhibit 10 invention, where effector function is not required, it is recognized that introducing a D265A mutation into the Fc region is something the skilled person could have easily conceived of on the basis of the common general knowledge.

…

Therefore, Corrected Invention 1 could have been easily invented by the skilled person on the basis of the Exhibit 10 invention and the common general knowledge at the time of the priority date, and is thus unpatentable under Patent Act Article 29(2).

Comments:

The defendant argued that “there were no circumstances in which D265A could have been selected from among the mutations that reduce binding to multiple FcγRs,” but the court rejected this, holding that “selecting the D265A mutation is nothing more than a matter of routine design for the skilled person.”

Kazuyuki YOSHIZUMI