Source: https://www.biosimilarsip.com/2018/08/01/ptab-institutes-a-second-ipr-on-rituxan-related-821-patent/
Timestamp: 2019-04-23 03:54:11+00:00

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The PTAB recently instituted a second IPR of US Patent 9,296,821 (“the ’821 patent”), which covers certain uses of Rituxan® (rituximab), a monoclonal antibody marketed by Genentech and Biogen Pharmaceuticals. The ‘821 patent claims methods of treating low grade or follicular non-Hodgkin’s lymphoma (NHL) by administering rituximab during a chemotherapeutic regimen of cyclophosphamide, vincristine, and prednisone (CVP therapy), wherein the method provides a beneficial synergistic effect. The recently-instituted IPR was filed by Pfizer (IPR2018-00186).
This decision presents an interesting example of how the Patent Trial and Appeal Board (“the Board” or “the PTAB”) may apply the Supreme Court’s decision in SAS Inst., Inc. v. Iancu, 138 S. Ct. 1348, 1360-61 (2018) to “follow-on petitions” in which a new petitioner challenges the same patent at issue in a prior petition or IPR by a third-party. The Board held that “when considering whether to exercise our discretion to deny institution under 35 U.S.C. § 325(d), we must consider not simply whether to deny institution regarding certain claims or certain challenges, but whether to do so regarding the petition, as a whole.” Institution Decision (IPR2018-00186, Paper 15) at 19. Here, Pfizer’s new argument as to a single claim persuaded the Board not to exercise its discretion to deny the Petition under § 325(d).
Last October, the PTAB instituted IPR of claims 1-3 and 5-6 of the ’821 patent based on a petition by Celltrion. (IPR2017-01095, Paper 12.) Following the Supreme Court’s decision in SAS, the Celltrion IPR was expanded to include all claims (i.e., claims 1-6) and all grounds raised in the petition. (IPR2017-01095, Paper 39.) That proceeding is pending, and oral argument is scheduled for August 21, 2018.
In the Celltrion institution decision, the PTAB preliminarily determined that claims 1-3 of the ’821 patent were entitled to a priority date of August 11, 1999, but gave claims 4-6 a priority date of June 15, 2012, the filing date of the application that issued the ’821 patent. In the recently-instituted Pfizer IPR (IPR2018-00186), the Board maintained this preliminary priority determination.
The priority date determination for claims 4-6 turns on whether the specification of the ’821 patent adequately describes “administering 375 mg/m2 of rituximab once every 3 weeks for 8 doses.” The Patent Owner, Biogen, argued that the specification discloses the claimed dosing regimen by teaching rituximab (375 mg/m2) in combination with “standard CVP therapy,” and that one skilled in the art would understand “standard CVP therapy” to be six to eight cycles of CVP spaced three weeks apart. Institution Decision (IPR2018-00186, Paper 15) at 13. The Board found, however, that the specification’s disclosure of “standard CVP therapy” was in the context of a study in which Rituximab® would be dosed weekly as maintenance therapy following CVP therapy. Id. At this stage in the proceeding, the Board found this inadequate to describe dosing once every 3 weeks for 8 doses, and accorded claims 4-6 a June 15, 2012 priority date. Id.
Pfizer also argued that the claim phrase “beneficial synergistic effect” is non-limiting as to claim 4, because it “essentially duplicates the dosage amounts recited in the claims’ and is nothing more than ‘an expression of intended result.’” Institution Decision at 6 (quoting Bristol-Myers Squibb Co. v. Ben Venue Labs., Inc., 246 F.3d 1368, 1375 (Fed. Cir. 2001)). The Board preliminarily agreed with Pfizer that, because claim 4 recites a specific dosing regimen for rituximab along with “standard CVP therapy,” the “beneficial synergistic effect” recited in the claim is “an intended result of administering the combination in the recited manner” and is not a claim limitation. Id. at 7.
Due to its preliminary decision that the priority date for claims 4-6 was June 15, 2012, the Board considered relatively recent references as prior art to those claims. Id. at 14. In particular, Marcus, published in 2005, describes a clinical trial comparing CVP and rituximab every 21 days for a maximum of 8 cycles to CVP alone. The Board found, on the current record, that Marcus describes every limitation of claims 4-6. Institution Decision at 15-16. The Board relied, in part, on its preliminary determination that the requirement for a “beneficial synergistic effect” is not a claim limitation. Id. at 16. Alternatively, the Board found a reasonable likelihood that Pfizer could show every limitation, including the beneficial synergistic effect, was rendered obvious by a combination of references.
The Board then addressed Biogen’s arguments that Pfizer’s petition should be denied under § 325(d) or §314(a) based on overlap with the Celltrion IPR. The Board agreed with Biogen that Pfizer’s obviousness challenges to claims 1-3 present “the same or substantially the same prior art and arguments presented in the Celltrion petition.” Institution Decision at 18. While the Board found “similarities” between Pfizer’s other challenges and those presented by Celltrion, it did not consider them “substantially the same.” In particular, the Board noted Pfizer’s challenges to claim 4, including its new argument that the term “beneficial synergistic effect” is non-limiting. The Board found these differences sufficiently distinguished Pfizer’s petition as a whole from Celltrion’s. Id. at 18-19.
The Board also declined to “expand” the General Plastics Industrial Co. v. Canon Kabushiki Kaisha, Case IPR2016-01357, Paper 19 (PTAB Sept. 6, 2017) decision to this case, noting Pfizer itself had not previously filed a petition on the ’821 patent.
In this case, the Board found that where a new Petitioner raises a substantially new argument as to at least one patent claim, the entire petition, including all challenged claims on all grounds, may be granted, despite a third party’s IPR having been instituted on the same patent on overlapping grounds.

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