IP Law Daily PTAB erred in requiring Sanofi to prove its proposed substitute claims for new prostate cancer treatment were patentable
Tuesday, February 5, 2019

PTAB erred in requiring Sanofi to prove its proposed substitute claims for new prostate cancer treatment were patentable

By Nicholas Kaster, J.D.

Treating the preamble of the proposed patent claim as non-limiting was error. On remand, the Board was directed to treat the preamble as an additional limitation of the proposed claim.

The Patent Trial and Appeal Board improperly placed the burden of proof on patent owner Sanofi to establish that its proposed claims for a new prostate cancer treatment were patentable and applied the wrong claim construction in its decision denying Sanofi’s motion to amend certain claims, the United States Court of Appeals for the Federal Circuit has ruled. Accordingly, the Board’s denial of Sanofi’s contingent motion to amend and its construction of the proposed substitute claims was vacated and the case remanded for further consideration (Sanofi Mature IP v. Mylan Laboratories Ltd., February 5, 2019, O'Malley, K.).

This action involves U.S. Patent No. 8,927,592 ("the ’592 patent"), which was assigned to Sanofi Mature IP. According to the ’592 patent, prostate cancer is generally treated with hormone deprivation. This can include surgery, e.g. castration. But if prostate cancer metastasizes, then castration is ineffective. The ’592 patent purports to provide these patients—"patients with castration resistant metastatic prostate cancer who have been previously treated with docetaxel"—with a new treatment option. This treatment involves administering an antitumoral agent, cabazitaxel, in combination with a corticoid such as prednisone or prednisolone.

In an inter partes review requested by Mylan Laboratories Limited, the Patent Trial and Appeal Board invalidated claims 1–5 and 7–30 of the ’592 patent for obviousness. Sanofi has not appealed this aspect of the Board’s decision.

Sanofi then filed an opposed motion to amend its claims by substituting proposed claims 31–34 for claims 27–30. The Board also denied Sanofi’s contingent motion to amend because, according to the Board, Sanofi failed to establish that its proposed claims would be patentable. Sanofi appealed the Board’s denial of its motion.

Proposed claim 31, like claim 27, requires administering cabazitaxel, in combination with prednisone or prednisolone, to a patient with castration resistant or hormone refractory metastatic prostate cancer who has progressed during or after treatment with docetaxel. According to the Board, "[s]ubstitute claim 31 amends the preamble [of claim 27] to recite a ‘method of increasing survival’ followed by ‘comprising administering to a patient in need thereof.’" Proposed claim 31 also limits claim 27 by requiring the administration of an antihistamine, a corticoid, and an H2 antagonist prior to administering the cabazitaxel. Proposed claims 32–34 depend directly from proposed claim 31.

In addressing Sanofi’s motion, the Board concluded that the preamble of proposed claim 31 was the only phrase requiring explicit construction. Sanofi argued that the preamble—"[a] method of increasing survival"—was a "statement of intentional purpose for how the method is to be performed." The Board disagreed, concluding that the preamble of proposed claim 31 should not be treated as limiting because it merely provides "additional description," rather than an "intentional purpose for how the treatment method is to be practiced." And, while Sanofi invited the Board to treat its claim construction arguments as a disclaimer, the Board declined to do so.

On the merits, Sanofi argued that the prior art did not disclose or suggest that 20–25 mg/m2 of cabazitaxel in combination with prednisone or prednisolone would increase overall survival, as required by the preamble to claim 31. The Board rejected this argument based on its construction of proposed claim 31, i.e. that the preamble was not limiting. Sanofi also argued that a skilled artisan would not have been motivated to use the claimed premedication regimen—administration of an antihistamine, a corticoid, and an H2 antagonist—prior to cabazitaxel therapy.The Board rejected this argument as well.

On appeal, Sanofi argued that the Board erroneously placed the burden of proof on Sanofi to show that its proposed claims would be patentable. Sanofi also appealed the Board’s construction of proposed claim 31, along with the Board’s ultimate conclusion that the proposed claims would be unpatentable.

In an inter partes review, the petitioner bears the burden of proving that proposed amended claims are unpatentable. But in deciding whether Sanofi could amend its claims here, the Board expressly required Sanofi to prove that its proposed substitute claims were patentable. This was an error, the appellate court concluded.

Even so, Mylan maintained that the Board’s error was harmless because the Board found that Mylan satisfied the burden of showing the proposed substitute claims were unpatentable by a preponderance of the evidence. The court disagreed. While the Board at times suggested Mylan had established certain facts, it also noted other failures of proof and gaps in Mylan’s expert testimony. The court therefore declined to speculate as to how the Board would resolve this case under the correct legal standard.

The court noted that a claim’s preamble may be limiting if it recites essential structure or steps, or if it is "necessary to give life, meaning, and vitality" to the claim." But, generally, a preamble is not limiting where a patentee defines a structurally complete invention in the claim body and uses the preamble only to state a purpose or intended use for the invention.

Sanofi argued that the preamble of proposed claim 31 was limiting and the court agreed, citing its holdings in Jansen v. Rexall Sundown, Inc., 342 F.3d 1329 (Fed. Cir. 2003) and Rapoport v. Dement, 254 F. 3d 1053 (Fed. Cir. 2001). The court noted that the phrase "patient in need thereof" from proposed claim 31 relied on the preamble for antecedent basis. In addition, the preamble expresses the intentional purpose—increasing survival—for which the method must be performed. The court’s conclusion was also consistent with the specification of the ’529 patent, which emphasizes increasing survival as an important aspect of the invention. There is a direct link, said the court, between the claim as a whole and the preamble, which provides an antecedent basis for "in need thereof."

Ultimately, the court concluded, the patent owner’s proposed claim 31 closely mirrored language from cases, such as Jansen and Rapoport, which has been treated as limiting. The Board erred by treating the preamble here as non-limiting, the court held. Therefore, on remand, the court ruled, the Board should treat the preamble as an additional limitation of proposed claim 31.

This case is No. 18-1203.

Attorneys: Daniel John Minion (Venable LLP) for Sanofi Mature IP. Matthew R. Reed (Wilson, Sonsini, Goodrich & Rosati, PC) for Mylan Laboratories Ltd.

Companies: Sanofi Mature IP; Mylan Laboratories Ltd.

MainStory: TopStory Patent FedCirNews

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