DR Reddys Laboratories SA v. Indivior Uk Ltd

1. Case Identification

• Case #: IPR2019-00329
• Patent #: 9,687,454
• Filed: November 13, 2018
• Petitioner(s): Dr. Reddy's Laboratories S.A. and Dr. Reddy's Laboratories, Inc.
• Patent Owner(s): Indivior UK Limited
• Challenged Claims: 1-5, 7-14

2. Patent Overview

• Title: Sublingual and Buccal Film Compositions
• Brief Description: The ’454 patent is directed to oral, mucoadhesive film compositions for treating opioid dependence. The films contain buprenorphine (an opioid agonist) and naloxone (an opioid antagonist), and use an acidic buffer to control pH, seeking to achieve bioequivalence with the prior art Suboxone® tablet.

3. Grounds for Unpatentability

Ground 1: Anticipation over Myers - Claims 1-5 and 7-14 are anticipated by Myers under 35 U.S.C. §102.

• Prior Art Relied Upon: Myers (Application # 2011/0033541).
• Core Argument for this Ground: Petitioner’s argument proceeded in two stages. First, Petitioner argued that the challenged claims of the ’454 patent were not entitled to the August 7, 2009 priority date of the parent '571 application. Petitioner contended the '571 application lacked written description support for specific polymer weight percentage ranges (e.g., "about 40 wt % to about 60 wt %") and buprenorphine-to-polymer ratios that were added during prosecution. Without this priority date, the claims’ effective filing date became post-AIA (after March 16, 2013), making Myers—the published version of the '571 application itself—qualifying prior art under §102. Second, Petitioner argued that while the '571 disclosure (i.e., Myers) lacked the "blaze marks" required for written description support of the ranges, its specific examples and teachings anticipated every limitation of the challenged claims.
  • Prior Art Mapping: Petitioner alleged that Myers anticipated all limitations of independent claim 1 and the dependent claims. For claim 1, Petitioner mapped Myers’ disclosures as follows:
    • [1a] Polymeric Matrix: Myers’ Table 1 disclosed formulations containing 48.2% and 58.6% polymer by weight, falling within the claimed "about 40 wt % to about 60 wt %" range.
    • [1b] Buprenorphine: Myers expressly taught a buprenorphine amount from "about 2 mg to about 16 mg," with examples in Table 1 matching this range.
    • [1c] Naloxone: Myers taught amounts from "about 0.5 mg to about 4 mg" to maintain a 4:1 ratio with buprenorphine, with examples provided.
    • [1d] Acidic Buffer: Myers taught using a buffer to control pH to a range of about 2 to 4 and disclosed using sodium citrate and citric acid, which Petitioner argued a POSA would understand to be an acidic buffer.
    • [1e] Mucoadhesive Film: Myers stated a desire to select polymers that provide "mucoadhesive properties to the film."
    • [1f] Buprenorphine:Naloxone Ratio: Myers disclosed that "most desirably, the film composition contains about 4:1 agonist to antagonist per dosage."
    • [1g] Buffer:Buprenorphine Ratio: Myers disclosed a desired ratio of "from about 2:1 to about 1:5," and its Table 1 formulations included ratios of 1:2 and 2:1, falling within the claimed range.
    • [1h] Pharmacokinetic Parameters: Myers disclosed the same Cmax and AUC ranges for both buprenorphine and naloxone as recited in the claim.
    • Petitioner further argued that Myers’ disclosures anticipated the narrower ranges and specific components required by dependent claims 2-5 and 7-14.

4. Key Claim Construction Positions

• "acidic buffer": Petitioner proposed this term be construed to mean "a weak acid [citric acid], its conjugate base [sodium citrate] or combinations of both that operate in the acidic pH range (i.e. less than pH 7.0)." This construction was central to arguing that the buffer systems disclosed in Myers, which included citric acid and sodium citrate, met the express limitation of claim 1. Petitioner noted this was consistent with the specification and a construction of "buffer" from a related district court case.

5. Key Technical Contentions (Beyond Claim Construction)

• Lack of Written Description Support in Priority Application: The central contention underpinning the entire anticipation ground was that the '571 application failed to provide adequate written description for the claimed polymer weight percentages and buprenorphine-to-polymer ratios. Petitioner argued the '571 text only provided open-ended ranges (e.g., "at least 25% by weight" polymer) and instructed that "any desired level" of polymer could be used. Petitioner contended this broad disclosure lacked the necessary "blaze marks" to direct a POSA to the specific, narrower ranges later claimed. Therefore, Petitioner argued that the patentee was "picking a tree out of the forest" by back-calculating ranges from a single example table (Table 1) without any indication in the original disclosure that these ranges were of particular inventive significance. This failure, Petitioner argued, severed the priority chain and rendered Myers intervening prior art.

6. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under 35 U.S.C. §325(d) would be inappropriate because the evidence and arguments were not previously considered by the USPTO. Specifically, Petitioner asserted that during prosecution, the Examiner never questioned the patent’s claim to priority, nor issued any office action concerning whether the claims had sufficient written description support under 35 U.S.C. §112 in the priority application. Consequently, the Examiner never considered whether Myers—which only becomes prior art if priority is denied—anticipated the claims.

7. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-5 and 7-14 of the ’454 patent as unpatentable.