Post Grant Review and Section 112: A Curious Case

In a case where it strikingly relied on prior art sharing a specification with the patent at issue, the USPTO’s Patent Trial and Appeal Board (PTAB) invalidated the patent on several grounds, including lack of written description and enablement under 35 U.S.C. § 112. US Endodontics, LLC v. Gold Standard Instruments, LLC, PGR2015-00019 (PTAB December 28, 2016). The PGR was instituted against claims 12-16 of US Patent No. 8,876,991, directed to titanium dental and medical instruments. There were, as noted, several grounds of institution, but this post will focus mostly on the PTAB’s analysis under § 112.

Claim 12, the only independent claim at issue, reads as follows:

A method for manufacturing or modifying an endodontic instrument for use in performing root canal therapy on a tooth, the method comprising:

(a) providing an elongate shank having a cutting edge extending from a distal end of the shank along an axial length of the shank, the shank comprising a superelastic nickel titanium alloy, and

(b) after step (a), heat-treating the entire shank at a temperature above 25°C up to but not equal to the melting point of the superelastic nickel titanium alloy,

wherein the heat treated shank has an angle greater than 10 degrees of permanent deformation after torque at 45 degrees of flexion when tested in accordance with ISO Standard 3630-1.

The first issue before the PTAB was whether this patent is even subject to post-grant review (PGR). The Patent Owner argued that the patent, which was filed in 2014 and claims priority back to 2004 through multiple continuations, a divisional, a PCT, and a provisional, is not subject to PGR because its priority date precedes first inventor to file under the AIA. The PTAB held that the Petitioner has the burden to prove that the Patent Owner is not entitled to the earlier priority date.

To make the claims eligible for PGR, Petitioner has to establish that the earliest priority date for the claims is on or after March 16, 2013. Petitioner argued that the disclosures in the priority chain, going all the way back to 2004, do not provide sufficient written description and enablement support for claims 12-16.

Therefore, for purposes of PGR, the earliest effective date of claims 12-16 is January 29, 2014, the date on which the claims were filed.

The PTAB agreed with Petitioner. It held that reliance on an earlier date under §§ 119, 120, 121, and 365 “is premised on disclosure of the claimed invention in the manner provided by §112(a)…” Since none of the specifications in the priority chain supported the claim recitations, the claims at issue are not entitled to the earlier priority date. Therefore, the PTAB held that PGR is appropriate despite the pre-AIA priority claim.

Turning now to enablement, Petitioner argued undue experimentation. “Petitioner argues that the Specification provides insufficient guidance regarding how to achieve the claimed permanent deformation result using the claimed heat treatment parameters.” “In particular, the claims do not specify a duration for heat-treating, encompass temperature ranges from above 25°C (claims 12, 13, 15, 16) or 300°C (claim 14) up to but not equal to the melting point of the alloy, and either do not specify a composition for the nickel titanium alloy (claims 12– 15) or include a range of 54–57 weight percent nickel (claim 16).” Op. at 17. Petitioner further showed that its own experiments based on the claims failed to reproduce the claimed results.

The PTAB considered that only Example 4 of the Specification supported the claimed deformation characteristics (greater than 10 degrees), noting that the temperature in that example was 500 degrees Celsius as opposed to 25 degrees Celsius, which is the bottom of the claimed range. The PTAB recognized, “when a range is claimed, there must be reasonable enablement of the scope of the range.” (Quoting AK Steel Corp. v. Sollac & Ugine, 344 F.3d 1234, 1244 (Fed. Cir. 2003)). Here, because heat-treating at 25 degrees Celsius does not yield the claimed results, the PTAB found that the claims were not enabled.

The PTAB also found that the Specification fails to provide a sufficient written description under §112(a) of the “wherein” clause of claim 12 because “the Specification does not demonstrate possession of heat- treatment at a temperature above 25° C up to but not equal to the melting point of the superelastic nickel titanium alloy that provides the deformation characteristic of the “wherein” clause.”

Finally, because the PTAB found that the claims are not entitled to the earlier priority date, the PTAB found that one of the earlier “priority” documents (one filed in 2008) is a §102 reference. “For the reasons discussed above…, we have determined that the effective filing date of claims 12–16 is January 29, 2014. Therefore, [US2008/0032260], which was published on February 7, 2008, qualifies as prior art under 35 U.S.C. § 102(a)(1).”

Thus, the PTAB found the patent claims invalid.

Lessons for Practice

There are a few interesting takeaways. The first is that the PTAB confirmed the Petitioner has the burden to establish that the patent is subject to AIA review. The second, and more interesting one to me, is that the PTAB held that the patent at issue does not provide sufficient written description support nor enable the claims, yet found a reference with the same specification provided sufficient written description and enablement to reject those same claims under §102. That’s contrary to how the MPEP defines § 102 prior art. MPEP § 2121 requires that § 102 prior art contain an enabling disclosure. It’s most likely an oversight, but curious nonetheless.

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