United States: Double The Trouble: Lack Of Priority Opens The Door To Unpatentability In An IPR Proceeding

Decision: Dr. Reddy’s Labs. S.A. v. Invidior UK Ltd., IPR2019-00329, Paper 21 (P.T.A.B. June 3, 2019)

Background:  In an inter partes review (“IPR”) institution decision, Dr. Reddy’s Labs., S.A. v. Indivior UK Ltd., No. IPR2019-00329, Paper 21 (P.T.A.B. June 3, 2019), the PTAB found that the challenged claims were not entitled to the priority date of an earlier-filed application in the priority chain due to lack of written description support. To add insult to injury, the earlier-filed application was then found to anticipate the challenged claims. Interestingly, neither party mentioned in their briefs­—nor did the PTAB in the institution decision—that the earlier-filed application shared an identical specification with the challenged patent.

By statute, IPR petitions may only include challenges “on a ground that could be raised under section 102 or 103 and only on the basis of prior art consisting of patents or printed publications.” 35 U.S.C. § 311 (b). Although § 112 challenges are not identified in the statute as a permissible basis for challenge in an IPR, this case provides an example of how an IPR petitioner can use a priority determination to avail itself of a challenge under § 112 to break the priority chain and create prior art against the claims.

Dr. Reddy’s Laboratories (“Petitioner”) filed a petition to institute an IPR of claims 1-5 and 7-14 of U.S. Patent No. 9,687,454 (“the ’454 patent”), owned by Indivior (“Patent Owner”). The ’454 patent, filed on January 6, 2016, claims priority through a series of continuations to U.S. Application No. 12/537,571 (“the ’571 application”), which was filed on August 7, 2009, and published on February 10, 2011.  Petitioner argued that the challenged claims in the ’454 patent were not entitled to the priority date of the ’571 application due to lack of written description support and were therefore anticipated under 35 U.S.C. § 102 by the ’571 application publication.

The ’454 patent is involved in several district court litigations, including one between Indivior and Dr. Reddy’s. The litigation between Indivior and Dr. Reddy’s is currently at the claim construction stage. Indivior Inc. v. Dr. Reddy’s Labs, S.A., No. 2:17-cv-07111 (D.N.J.).

The ’454 patent claims a mucoadhesive film dosage form of a prior art tablet containing the active ingredients buprenorphine and naloxone for the treatment of narcotic dependence. Claim 1, the only independent claim, reads as follows:

1. An oral, self-supporting, mucoadhesive film comprising:
(a) about 40 wt % to about 60 wt % of a water-soluble polymeric matrix;
(b) about 2 mg to about 16 mg of buprenorphine or a pharmaceutically acceptable salt thereof;
(c) about 0.5 mg to about 4 mg of naloxone or a pharmaceutically acceptable salt thereof; and
(d) an acidic buffer;

wherein the film is mucoadhesive to the sublingual mucosa or the buccal mucosa;
wherein the weight ratio of (b):(c) is about 4:1;
wherein the weight ratio of (d):(b) is from 2:1 to 1:5; and
wherein application of the film on the sublingual mucosa or the buccal mucosa results in differing absorption between buprenorphine and naloxone, with a buprenorphine Cmax[1] from about 0.624 ng/ml to about 5.638 ng/ml and a buprenorphine AUC from about 5.431 hr*ng/ml to about 56.238 hr*ng/ml; and a naloxone Cmax from about 41.04 pg/ml to about 323.75 pg/ml and a naloxone AUC from about 102.88 hr*pg/ml to about 812.00 hr*pg/ml.

Petitioner argued that the ’571 application, to which the ’454 patent claims priority, lacked written description support for the limitations directed toward the amount of polymer in the claimed mucoadhesive film. Dr. Reddy’s Labs. S.A. v. Invidior UK Ltd., IPR2019-00329, Paper 1, at 20. The polymer limitations in the challenged claims are expressed in two forms. First, the polymer amount is expressed as a percentage of the overall weight of the film, e.g., “about 40 wt % to about 60 wt % of a water-soluble polymeric matrix” in challenged claim 1. Second, the polymer amount is expressed as a ratio relative to the amount of buprenorphine, e.g., “the weight ratio of (b):(a) is from about 1:3 to about 1:11.5” in challenged claim 5. Id.

Claim 5 reads:

The film of claim 1, wherein the weight ratio of (b):(a) is from about 1.3 to about 1:11.5

Petitioner asserted that there was only one short paragraph in the ’571 application that discussed the polymer amount and argued that this description could neither direct a person of ordinary skill in the art (POSA) to the claimed polymer amount ranges nor demonstrate to a POSA that the inventors were in possession of the claimed ranges. Id. at 21, 26.

The ‘571 application paragraph in its entirety reads:

The film may contain any desired level of self-supporting film forming polymer, such that a self-supporting film composition is provided. In one embodiment the film composition contains a film forming polymer in an amount of at least 25% by weight of the composition. The film forming polymer may alternatively be present in an amount of at least 50% by weight of the composition. Id. at 21.

With regard to the weight percentage range, Petitioner did not dispute that the claimed range (about 40% - about 60%) in challenged claim 1 was within the range disclosed in the specification (at least 25%). Nonetheless, Petitioner pointed out that “the disclosure of a broad range of values does not by itself provide a written description support for a particular value within the range.” Id. at 22, citing Gen. Hosp. Corp. v. Sienna Biopharm., Inc., 888 F.3d 1368, 1372 (Fed. Cir. 2018).

Petitioner further cited Federal Circuit caselaw, which held that in evaluating whether a disclosure provides a sufficient written description, “one cannot disclose a forest in the original application, and then later pick a tree out of the forest and say here is my invention. In order to satisfy the written description requirement, the blaze marks directing the skilled artisan to that tree must be in the originally filed disclosure.” Purdue Pharma L.P. v. Faulding Inc., 230 F.3d 1320, 1326-27 (Fed. Cir. 2000). Id. at 19.

Petitioner argued that the short description with open-ended ranges in the ’571 application could not provide “blaze marks” to direct a POSA to the closed ranges in challenged claims 1 and 5. IPR2019-00329, Paper 1, at 21 and 26.

Petitioner further argued that there was no indication in the ’571 application that the inventors gave any importance to the amount of polymer in the films. Id. For example, Petitioner alleged that the ’571 application did not contain any description that the specific amount of polymer had any impact on the properties of the film. Id. at 27.

To the contrary, the Petitioner pointed out that the ’571 application indicated that “any” amount of polymer could be used in the film. Id. at 26. There was simply no reason, Petitioner argued, that a POSA would understand the inventors to have been in possession of the limitations directed toward specific ratios of two ingredients that the application taught could be present in “any” amount. Id. at 25-26.

Petitioner further argued that the specific experimental data in Table 1 would not satisfy the written description requirement, because nothing in the ’571 application would direct a POSA to back-calculate “seemingly random ranges and ratios from one of the many examples.” Id. at 26.

Having concluded that the ’571 application could not provide an adequate written description to support the challenged claims in the ’454 patent, Petitioner contended that the challenged claims were not entitled to the priority date of the ’571 application. The ’571 application publication would then become anticipatory prior art against the challenged claims because, even though claimed amount ranges had no written description support in the publication of the ‘571 application, specific polymer weight percentages and (b):(a) ratio values back-calculated from the experimental data fell within the claimed ranges. Id. at 30. In other words, the very “back-calculation” that did not pass muster under the written description requirement, was adequate to establish anticipation.

In the Patent Owner Preliminary Response, Patent Owner disputed the Petitioner’s characterization that the inventors did not give any importance to the polymer amounts. Dr. Reddy’s Labs. S.A. v. Invidior UK Ltd., IPR2019-00329, Paper 12, at 7-8. Patent Owner cited text in the specification to show that the polymer amounts were important to the properties and function of the film. Patent Owner relied on the experimental data disclosed in Tables 1 and 5 to support the claimed numerical ranges of polymer amount and the (b):(a) ratio. Id. at 10.

Specifically, Patent Owner argued that back-calculations from data in these tables yielded polymer weight percentages of 48.2% and 56.8%, thus supporting both endpoints of the 40%-60% claimed range. Id. at 11-13. Patent Owner further argued that a POSA would understand the “at least 25%” and “at least 50% supported the “60%” endpoint. Id. at 14.

Patent Owner analogized this case to In re Wertheim, where the CCPA held that a disclosed range of 25% - 60% with specific embodiments of 36% and 50% could support the claimed range of 35% - 60%. 541 F.2d 257, 264 (C.C.P.A. 1976). Patent Owner asserted that a range of “at least 25%” together with specific values of 48.2% and 56.8% were sufficient to support both the endpoints and the range of “about 40% - about 60%” in the challenged claims. Accordingly, Patent Owner argued that the challenged claims in the ’454 patent were supported by the ‘571 application and thus entitled to its filing date such that the ‘571 application publication was not prior art.  Id. at 15.

Apparently purposefully, Patent Owner did not hedge its bet by arguing that the ‘571 application publication, if found to be prior art, did not anticipate the ’454 patent claims.

The PTAB panel was persuaded by Petitioner and concluded that the ’571 application did not have an adequate written description to support the challenged claims in the ’454 patent.

With regard to the polymer weight percentage, the Panel found that:
Although Patent Owner pieces together teachings of the specific weight percentages (48.2% and 58.6%) and ranges (at least 25% or 50%) in an attempt to show written description support, there is simply no disclosure of “about 40 wt % to about 60 wt %” of a polymeric matrix in the ’571 application.  

IPR2019-00329, Paper 21, at 20. The Panel also found that:

Patent Owner’s argument that a POSA would have a certain level of “confidence” that the inventors possessed endpoints or ranges does not satisfy the requirement that a POSA be able to “immediately discern the limitation at issue in the claims. See Purdue Pharma, 230 F.3d at 1323.

Id.

The PTAB analogized the facts in this case to those in Gen. Hosp. Corp. v. Sienna Biopharmaceuticals, Inc., 888 F.3d 1368 (Fed. Cir. 2018). In General Hospital, the Federal Circuit held that:

The disclosure of a range of concentrations from less than 1 x 10¹¹ particles per ml to some unidentified maximum, does not provide written description support for the claimed concentration of “about 6.6 x 10¹¹ particles per ml,” nor does the disclosure of particular discrete values within that range, none of which are the claimed value.

Id. (quoting Gen. Hosp. Corp.., 888 F.3d at 1370-71).

Accordingly, the panel here held that:

neither the range from at least 25% (or at least 50%) by weight of the composition to some unidentified maximum, nor the disclosure of discrete values within some range (48.2 wt % and 58.6 wt %), provides written description support for the claimed range of “about 40 wt % to about 60 wt %” of a polymeric matrix.

Id. at 21.         

The PTAB also rejected Patent Owner’s reliance on In re Wertheim, distinguishing the facts in this case:

The disclosure at issue in Wertheim, for purposes of providing written description support, described a range of 25% to 60% solids, i.e. a range having a specific disclosed endpoint of 60%. Wertheim, 541 F.2d at 264. Here, the ’571 application provides no disclosure of a range endpoint, leading a POSA to speculate as to what that endpoint might be. See Lockwood, 107 F.3d at 1572.

Id.

Similarly, the PTAB found that the ’571 application did not provide written description support for the amount limitations directed toward the range of the (b):(a) ratio. Id. at 23-24. The panel first pointed out that the limitations at issue recited ratios in the form of a range, rather than specific values. Id. Even for the specific values, the PTAB held that the ’571 application could not provide written description support, distinguishing “could calculate” from “would calculate”:

At most, a POSA having a reason to do so, could calculate specific ratios of 1:2.8 and 1:10.9 from Tables 1 and 5 of the ’571 application. But we find no reason for a POSA to calculate the (b):(a) ratio from the ’571 application.

Id. at 24.

The PTAB indicated that this case was like Purdue Pharma, in which there was nothing in the specification that would suggest to a POSA that the ratio was “an important defining quality of the invention,” nor did the disclosure even motivate one to calculate the ratio. Id. (citing Purdue Pharma, 230 F.3d at 1327).

Having decided that the challenged claims were not entitled to the asserted priority date and therefore the ’571 application publication qualified as prior art, the PTAB quickly disposed of the anticipation issue. The PTAB agreed with Petitioner that the specific examples disclosed in the ‘571 application included values that fell within the claimed range: the ‘571 application “discloses the limitations of claim 1” and “all the limitations of [claims 2-5 and 7-14].” Id. at 27-28. For these reasons, the PTAB found that Petitioner met the burden to demonstrate the reasonable likelihood to prevail with regard to at least one of the challenged claims.

Practice Take-Away

This case illustrates how a priority challenge based on a lack of written description can transform itself into an attack on patentability in an IPR proceeding. Written description issues often find their way into IPR proceedings when the parties have disputes over the priority date of a challenged claim or of an alleged reference.

The PTAB sanctioned this practice because “there was a difference between compliance with the requirements of 35 U.S.C. § 112 and assessing the earliest priority date for a claim.” SAP America, Inc. v. Pi-Net Int’l, Inc., No. IPR2014-00414, Paper 11, at 13 (P.T.A.B. Aug. 18, 2014). Therefore, parties raising written description concerns in this manner were not impermissibly challenging the patentability of a patent under 35 U.S.C. § 112, but instead were simply (and appropriately) challenging the priority date assertion. See id.

Disputes over the priority date of a patent or patent application can occur when the patentee has converted a provisional application to a non-provisional application, see, e.g., Butamax Advanced Biofuels LLC v. Gevo, Inc., IPR2013-00539, Paper 33 (P.T.A.B. Mar. 3, 2015), and when the patentee has filed a continuation-in-part application. See, e.g., Propel Orthodontics, LLC v. Orthoaccel Techs., Inc., IPR2018-00296, Paper 36 (P.T.A.B. June 10, 2019).

For example, the specification of the later-filed application (i.e., the challenged patent) may contain disclosure of new matter that was not included in the earlier-filed “priority” application. If the invention claimed in the later-filed application (i.e., the challenged patent) lacks written description support in the earlier-filed application, the claims in the later-filed application (i.e., the challenged patent) are not entitled to the prior filing date of the earlier-filed application.

This creates an opening for an IPR petitioner to challenge the patentability of a claim by, first, snipping the priority chain of the challenged claim, and, second, asserting intervening art against the claim. In this situation, because the intervening art published after the asserted priority date of the challenged claim but before the actual filing date of that claim, that intervening art only becomes prior art if and when the challenged claim loses its priority date and can only rely upon its actual filing date.

Dr. Reddy’s Labs. v. Invidior, IPR2019-00329, however, presents two twists to the classic intervening art fact pattern. First, there is no new matter. The specification of the earlier-filed application and specification of the later-filed application (i.e., the challenged patent) are identical. Any written description challenge made against the priority of the earlier-filed application could also be made verbatim against the patentability of the later-filed application (i.e., the challenged patent).

Second, having defeated an earlier priority date, the petitioner did not rely on any independent intervening patent or printed publication to challenge the patentability of the claims at issue. The only prior art the petitioner relied on here was the published specification of the earlier-filed application itself, which, ironically, was an identical disclosure to the specification of the challenged patent. Thus, the patentee’s own identical disclosure became prior art and was used against the challenged claims. 

In this case, the only issue was written description support. After losing the written description argument in the priority battle, the patent owner did not have a defensible position against the patentability attack. The challenged claims were hopelessly vulnerable in view of the identical specification of the very patent challenged in the IPR.

Given those facts, the patent owner was helpless to make any counterargument against the petitioner’s anticipation contention. The anticipation was so apparent that the PTAB spent fewer than three pages of its 29-page institution decision discussing anticipation. In this case, the IPR petitioner clearly used the lack of written description in the earlier-filed application as a vehicle to launch a patentability challenge based on inadequate written description of the challenged claims 1-5 and 7-14.

The success of this strategy requires two elements: a vehicle, that is, an earlier-filed application in the priority chain that was published more than one year before the filing date of the patent at issue. The publication of the earlier filed application would become a pre-AIA § 102(b) piece of prior art or an AIA § 102(a)(1) piece of prior art when the priority chain is severed. In addition, the published earlier-filed application must fail to provide adequate written description to support the full scope of the challenged claim while disclosing embodiments that anticipate the challenged claim. In other words, as seen in this case, there was no adequate written description of challenged claims 1-5 and 7-14, but there were disclosed species that anticipated the challenged claims.

Two types of situations could possibly benefit from this strategy. First, a situation in which the challenged claim is directed to a genus, and the specification of the patent discloses some species within the genus. Second, a case in which the challenged claim is directed to a numerical range, and the specification discloses discreet values within the range but not the range itself. In both of these situations, like in this case, the disclosed species or values in the earlier publication may not provide an adequate written description to support the claimed genus or range, but they would nonetheless anticipate the claimed genus or range.

Not every situation can follow the same strategy to success, as all cases depend on their own particular facts and circumstances. For example, if the written description challenge is based on the failure to disclose claim elements (other than, e.g., amounts) in the specification, it would be difficult to rely on the earlier-filed and published application as anticipatory prior art. But, one should consider whether the published application would have rendered obvious relevant claims. And certainly, the Petitioner might use later litigation to challenge the validity of patent claims based on a failure to comply with § 112.

To qualify as anticipatory prior art, the specification would need to disclose every element of the challenged claim, or at least an embodiment of each element. In that case, the IPR petitioner would still be incentivized, as here, to repackage a written description challenge on patentability into a written description challenge on priority as long as there is no written description but there is enough disclosure to mount an anticipation attack. If the patent at issue were to lose benefit of an earlier priority date, the challenged claim would be exposed to intervening prior art, including, perhaps, as here, an identical, earlier-filed specification. In addition, even if the publication of the earlier-filed application would not anticipate the challenged claim, it may, if the priority chain is severed, still serve, as noted above, as § 103 prior art that renders the challenged claims unpatentable as obvious.

There seems to be no reason to fear that this practice would push the limits of the PTAB’s tolerance levels. Following the approach of this case, the petitioners in IPR cases, having a strategic set of facts, could present patentability challenges based on inadequate written description by predicating them as priority challenges against earlier-filed and published applications that share the same specification as the patents at issue.

To date, the PTAB has seemingly been receptive of this practice. In another recent IPR case, the PTAB held that:

As an initial matter, we reject Patent Owner’s argument that we should deny Petitioner’s grounds based on Kordunsky because Petitioner’s arguments are a back-door effort to challenge validity under 35 U.S.C. §112 in violation of the AIA. See Prelim. Resp. 25. According to Patent Owner, “the ‘504 patent is one patent in a chain of continuations, all of which undisputedly share an identical disclosure. Thus, Petitioner’s request for a ‘priority’ determination is nothing other than a request that the Board invalidate the challenged claims under §112. Id. at 26.” (emphasis in original). 

Patent Owner’s complaint that “it would be pointless for the Board to actually address the ‘anticipation’ issue if it decides the predicate §112 issue in Petitioner’s favor” (Prelim. Resp. 26), although understandable, is of no moment in our analysis of this Petition for an inter partes review.

Agilent Techs., Inc. v. Bio-Rad Labs., Inc., IPR2019-00266, Paper 8, at 12-13 (P.T.A.B. May 16, 2019).

While this practice seems to be here to stay, the estoppel consequences are interesting to consider if the IPR is instituted and a Final Written Decision issues. Under SAS Institute, Inc. v. Iancu, 138 S. Ct. 1348 (U.S. 2018), there are no longer partial institutions, so each petition is either instituted on all challenged claims and all grounds or denied in its entirety. But if the petition is instituted, and then Petitioner loses the IPR in the Final Written Decision, would Petitioner be estopped from making invalidity challenges based on the same or different written description arguments in a later district court proceeding?

It appears that there is no statutory basis for the estoppel. Under 35 U.S.C. § 315(e)(1), the petitioner is estopped from arguing against the same claim “on any ground that the petitioner raised or reasonably could have raised during that inter partes review.” The “grounds” are set forth in 35 U.S.C. § 311(b) as “section 102 or 103 and only on the basis of prior art consisting of patents or printed publications.” IPR does not allow for direct attacks on the patentability of claims under § 112.

Following the practice in this case, the petitioner technically only challenged the priority status of the earlier-filed application and did not make, as it could not under the current law, any § 112 patentability argument against the challenged claims. Therefore, even if a Final Written Decision issued and the challenged claims survived, the petitioner, although losing the written description argument during the IPR, probably could still present a validity challenge on the basis of inadequate written description in a later court proceeding. Whether the court would prevent the petitioner, on equitable grounds, from rehashing the same written description argument has not yet been decided.

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