Cabazitaxel - USA

On Feb 05, 2019, Federal Circuit vacated & remanded PTAB’s invalidation of proposed amended claims of a method-of-use patent, finding the board improperly placed the burden of proof on Sanofi to establish that its proposed claims were patentable and applied the wrong claim construction in its analysis.

This appeal involves U.S. Patent No. 8,927,592 (expiring on 04/27/2031 with PED), claims method for treatment of castration resistant metastatic prostate cancer with cabazitaxel & corticoid. In an inter partes review requested by Mylan PTAB invalidated claims 1–5 and 7–30 of the ’592 patent. The Board also denied Sanofi’s contingent motion to amend claims 27–30. Specifically, on Dec 23, 2016, Sanofi filed an opposed motion to amend its claims by substituting proposed claims 31–34 for claims 27–30. (“If original Claim 27 is found unpatentable, the Board is requested to replace it with proposed substitute Claim 31.”). Proposed substitute claim 31 recites:

31. A method of increasing survival comprising administering to a patient in need thereof (i) an antihistamine, (ii) a corticoid, (iii) an H2 antagonist, and (iv) a dose of 20 to 25 mg/m2 of cabazitaxel, or a hydrate or solvate thereof, wherein said antihistamine, said corticoid, and said H2 antagonist are administered prior to said dose of 20 to 25 mg/m2 of cabazitaxel, or hydrate or solvate thereof, in combination with prednisone or prednisolone, wherein said patient has castration resistant or hormone refractory, metastatic prostate cancer that has progressed during or after treatment with docetaxel.

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. But, as the Board noted, “[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.

On Sep 21, 2017, the Board issued its final written decision. First, the 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 appealed the Board’s denial of its motion to amend the claims & improper burden of proof to show that its proposed claims would be patentable. 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, distinguishing Jansen in favor of Bristol–Myers Squibb Co. v. Ben Venue Laboratories, Inc., 246 F.3d 1368, 1375–78 (Fed. Cir. 2001). (“Bristol–Myers Squibb is relevant precedent and stands for the proposition that a method of treatment preamble stating the intended purpose of the treatment does not impose a result limitation on the recited method step.”). The Board, therefore, concluded that the preamble of proposed claim 31 should not be treated as limiting because it merely provides “additional description,” as in Bristol-Myers Squibb, rather than an “intentional purpose for how the treatment method is to be practiced.” Sanofi also invited the Board to treat its claim construction arguments as a disclaimer, but the Board declined to do so. On the merits, Sanofi argued “that the prior art d[id] 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.

Burden of Proof:

Federal Circuit said that in an inter partes review, the petitioner bears the burden of proving that proposed amended claims are unpatentable. Aqua Prods., 872 F.3d at 1327–28. 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. Even so, Mylan maintains that the Board’s error was harmless because the Board “found that [Mylan] satisfied the burden of showing the proposed substitute claims are unpatentable by a preponderance of the evidence.”  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. Federal Circuit, therefore, vacated the Board’s denial of Sanofi’s contingent motion to amend and remanded for proceedings consistent with its decision in Aqua Products.

Claim Construction:

Federal Circuit reviewed the Board’s conclusions of law de novo and its findings of fact for substantial evidence. Federal Circuit said 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.” Catalina Mktg. Int'l, Inc. v. Coolsavings.com, Inc., 289 F.3d 801, 808 (Fed. Cir. 2002). 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.’” (quoting Rowe v. Dror, 112 F.3d 473, 478 (Fed. Cir. 1997)). Sanofi argued that the preamble of proposed claim 31 is limiting based on decisions in Rapoport v. Dement, 254 F.3d 1053 (Fed. Cir. 2001) as it articulated the “purpose for which the method must be performed.” The phrase here “patient in need thereof” from proposed claim 31 relies on the preamble for antecedent basis. And, as in Jansen, the preamble expresses the “intentional purpose [—increasing survival—] for which the method must be performed. Federal Circuit, therefore, “interpreted the nearly parallel language in the [’592] patent claims in the same way.” Federal Circuit further said that this is also consistent with the specification of the ’529 patent, which emphasizes increasing survival as an important aspect of the invention. The Board, thus erred by treating the preamble here as non-limiting.

Previously by an order of Dec 17, 2017, New Jersey district court found US’ 529 claims 7, 11, 14, 15, 16, 21, 26, and 30 invalid & claims 1 and 2 valid and infringed by Defendants’ proposed generic products (reported here on this blog). The said decision is under appeal at CAFC.