“Nearly All” Not Quite Good Enough to Achieve Discretionary Denial Under §325(d)

Holding

In Fusion Pharms., Inc. v. Univerität Heidelberg, IPR2023-00551, the Patent Trial and Appeal Board (“PTAB”) instituted inter partes review (“IPR”), rejecting Patent Owner’s §325(d) argument.

Background

Fusion Pharms. petitioned for IPR of claims 1, 2, and 4-13 of U.S. Patent No. 10,980,901 (“the ’901 patent”). Id. at *2. The ’901 patent is directed to “a method of treating prostate specific membrane antigen (‘PSMA’) expressing cancers.” Id. at *3. Independent claim 1 reads:

1. A method for treating PSMA expressing cancers, wherein the method comprises administering to a patient in need thereof an effective amount of one or more Ac-225-radiopharmaceuticals, said one or more Ac-225-radiopharmaceuticals comprising Ac-225 chelated with a targeting compound of Formula (A), (B), (C), (D) or (E): …

Dependent claim 2 is written as a Markush claim:

2. The method of claim 1, wherein the one or more Ac-225 radiopharmaceuticals are selected from…[several compounds].

Patent Owner argued that the PTAB should deny the petition under §325(d) because Petitioner relied on a reference, Weineisen 2015, that is substantially the same as art and arguments previously presented to the Office. Specifically, “Patent Owner asserts that Weineisen 2015 is cumulative of the claims recited in Eder ’791 and Eder ’160, which were before the Office and which recited nearly all of the other members of the claimed Markush group recited in the ’901 patent.” Id. at *11-12. Patent Owner argued “[t]he challenged claims each recite a Markush group covering the general structure of a number of PSMA-targeting ligands” but Petitioner “fails to mention that several other PSMA-targeting ligands covered by the challenged claims . . . were disclosed in the prior art considered by the Examiner.” Id. at *12.  

Petitioner argued that Weineisen 2015 disclosed the use of a particular chelating ligand termed “PSMA I&T” with beta-emitting radionuclides (68GA and 177Lu). Id. at *10-11. PSMA I&T is the same compound as that shown in claim 1, Formula C of the ’901 patent. Id. at *11.

PTAB

The PTAB concluded that neither Weineisen 2015 nor the specific PSMA I&T ligand disclosed in Weineisen 2015 was before the Office or considered by the Examiner and was not “substantially similar or cumulative”:

Just because the Eder ’160 patent claims disclose many of the members of the Markush group recited in the ’901 patent claims does not mean that all the members of the Markush group are represented or encompassed by the Eder ’160 claims… Here, the species disclosed in the Weineisen 2015 reference is not present in the Eder ’160 patent claims. Accordingly, we determine that the Weineisen 2015 [is] not substantially similar or cumulative to the art previously presented to the Office.

Id. at *13 (citation omitted). Since the first part of the Advanced Bionics framework was not satisfied (determining whether the same or substantially the same art/arguments were previously presented to the Office), the PTAB did not proceed to the second part (whether the petitioner has demonstrated that the Office erred in a manner material to the patentability of challenged claims). Id. at *13. Accordingly, the PTAB did not exercise its discretion under §325(d) to deny the petition. Id. at *14.  

Take-Aways

As set out in M.P.E.P. 803.02 [R-07.2022], “a Markush grouping is proper if: (1) the members of the Markush group share a ‘single structural similarity,’ and (2) the members share a common use.”

But in this case the PTAB found disclosure of nearly all the members of a Markush grouping was not enough to exercise its discretion to deny institution under §325(d) because “the species disclosed in the Weineisen 2015 reference is not present in the Eder ’160 patent claims.”

Patent Owners may take this case as a caution for relying on genus/species arguments when requesting discretionary denial under §325(d) of petitions challenging Markush claims where the newly-cited reference discloses a species not specifically named in a Markush grouping.