Does PATO need to explain why something is obvious in an inter partes review? MERCK v. WYETH

A patent is a government granted monopoly on an invention for a limited period of time, issued to the inventor of an invention. An inventor can apply for a patent in the United States by filing a patent application with the United States Patent and Trademark Office. For the patent application to be granted by the United States Patent and Trademark Office the inventor must demonstrate that the invention new, useful and not obvious. If the USPTO grants the patent application, the inventor is granted the exclusive right to use make sell and import the machine into the United States. If someone other than the inventor exercises one of the exclusive rights granted by a patent, this is known as patent infringement. A patent owner can request and injunction from a court to stop patent infringement and can sue to recover monetary damages for patent infringement which has occurred.

After a patent is granted it is still subject to review. The America Invents Act introduced inter partes review, which is a method to get a patent declared invalid. Inter partes review is a trial proceeding conducted at the Patent Trial and Board (PTAB) to review the patentability of one or more claims in a patent only on a ground that could be raised under §§ 102 or 103, and only on the basis of prior art consisting of patents or printed publications.

Inter partes review is a quasi judicial proceeding performed by the PTAB. This means that there are certain formalities that must be followed. One of those formalities is that all decisions of the PTAB must be explained and supported by the evidence. If the PTAB fails to properly explain its conclusions, then its decision is subject to reversal by an appellate court.

MERCK SHARP & DOHME CORP. v. WYETH LLC, 2018-2133 (C.A.F.C. 2019) is a case that illustrates what happens when the PTAB does not completely explain its reasoning in a decision. The defendant in this case owns U.S. Patent No. 8,562,999 which relates to formulations for stabilizing polysaccharide-protein conjugate vaccines. The plaintiff in this case petitioned for inter partes review on the grounds that all claims of the patent were obvious.

The PTAB found all the challenged claims except one—claim 18—to be unpatentable as obvious. Claim 18 covers a 13-valent pneumococcal conjugate vaccine. The plaintiff claimed that the combination of two pieces of prior rendered claim 18 obvious. The PTAB rejected the plaintiff’s argument that the formulation recited by claim 18 was obvious in light of the prior art. In its decision the PTAB clearly laid out the reasons why all the claims, other than claim 18 were obvious. With respect to claim 18 the PTAB stated that the prior art did not show that a combination was considered, tried and successful.

The Federal Circuit found that the PTAB did not address the evidence as to whether someone skilled in the art would have been motivated to combine the 13 serotypes into a CRM197 conjugate or whether the potential loss of immunogenicity would have dissuaded someone skilled in the art from making such a combination. The fact that the prior art did not disclose such a combination fails to answer this central question, and an explanation was particularly necessary given the Board’s finding that the use of CRM197 was obvious with the 7-valent conjugate in claim 17—which also uses CRM197 as a sole carrier protein.

The Federal Circuit vacated PTAB’s obviousness findings with respect to claim 18, and remanded for further consideration of the parties’ arguments and evidence as to (1) motivation to combine and (2) reasonable expectation of success and, if the PTAB finds a sufficient motivation to combine and reasonable expectation of success, other issues such as secondary considerations.

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