PTAB

IPR2025-00033

Cipla Ltd v. Gilead Sciences Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Therapeutic Compositions for Treatment of Human Immunodeficiency Virus
  • Brief Description: The ’802 patent discloses a single-tablet, fixed-dose pharmaceutical composition for treating Human Immunodeficiency Virus (HIV). The composition comprises three active ingredients: the integrase strand transfer inhibitor (INSTI) bictegravir (BIC), and two nucleoside/nucleotide reverse transcriptase inhibitors (N(t)RTIs), tenofovir alafenamide (TAF) and emtricitabine (FTC).

3. Grounds for Unpatentability

Ground 1: Claims 1-13 are obvious over WO '323 in view of WO '351.

  • Prior Art Relied Upon: WO '323 (WO 2014/100323) and WO '351 (WO 2015/022351).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that WO '323 discloses a new family of INSTIs, including bictegravir (BIC, identified as Compound 42), and teaches combining them with other anti-HIV agents like TAF and FTC in a single, unitary dosage form such as a tablet. WO '351 was asserted to disclose combining the structurally similar "second generation" INSTI dolutegravir (DTG) with the specific claimed dosages of TAF (25 mg) and FTC (200 mg) in a single tablet. Petitioner contended that substituting the BIC from WO '323 for the DTG in WO '351 would result in the claimed invention.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) would combine these references due to: (1) a recognized clinical need and market pressure for an improved single-tablet regimen (STR) combining a safer N(t)RTI backbone (TAF/FTC) with a potent, second-generation INSTI; (2) BIC's high structural and functional similarity to the well-known DTG, making BIC an obvious "me-too" substitute for Gilead to develop; and (3) the established need for smaller tablets, which replacing the older tenofovir disoproxil fumarate (TDF) with the lower-dose TAF achieves.
    • Expectation of Success: A POSA would have a high expectation of success because combining known anti-HIV drugs into an STR was a well-established and predictable practice. The close structural similarity between BIC and DTG suggested they would have similar physicochemical properties and biological activity, making the combination's success predictable.

Ground 2: Claims 1-13 are obvious over WO '323 and WO '351 in view of Bowker and Paulekuhn.

  • Prior Art Relied Upon: WO '323 (WO 2014/100323), WO '351 (WO 2015/022351), Bowker (a 2002 handbook chapter on salt selection), and Paulekuhn (a 2007 journal article on salt selection trends).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground incorporated the arguments from Ground 1 and added Bowker and Paulekuhn to render obvious the dependent claims reciting specific salts (e.g., BIC sodium). Petitioner argued that Paulekuhn taught a POSA that sodium was the most common cation used for formulating acidic drugs. Bowker provided the scientific rationale, teaching that a stable salt is formed when there is a pKa difference of at least three units between the acidic drug and the base, a condition met by the weakly acidic BIC and the strong base sodium hydroxide.
    • Motivation to Combine: The motivation was to engage in routine optimization of BIC's physicochemical properties for a pharmaceutical formulation. Given that the structurally analogous DTG was successfully marketed as a sodium salt, and both compounds share a similar acidic hydroxyl group, a POSA would have been motivated to apply the known principles from Bowker and trends from Paulekuhn to create a stable, pharmaceutically acceptable sodium salt of BIC.
    • Expectation of Success: Success was expected because forming a BIC sodium salt relies on fundamental acid-base chemistry, the principles of which were well-understood and detailed in Bowker, and which had been successfully applied to the analogous compound DTG.

Ground 3: Claims 1-13 are obvious over WO '323 and WO '351 in view of US '079.

  • Prior Art Relied Upon: WO '323 (WO 2014/100323), WO '351 (WO 2015/022351), and US '079 (Application # 2015/231079).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built on the combination in Ground 1, adding the '079 application to address the obviousness of the tablet weight limitations in dependent claims 9-13. The '079 application taught a preference for single-tablet formulations to improve patient compliance and exemplified a DTG/TDF/FTC tablet with a total drug weight of 550 mg and a total coated weight of 1055 mg.
    • Motivation to Combine: A POSA would be motivated by the desire for smaller tablets to enhance patient adherence. The obvious combination from Ground 1 (50 mg BIC / 25 mg TAF / 200 mg FTC) results in a total drug weight of 275 mg, approximately half that of the tablet in the '079 application. A POSA would have been motivated to reduce the amount of excipients proportionally, resulting in a significantly smaller tablet that would fall well within the claimed weight limitations.
    • Expectation of Success: A POSA would expect success in creating a smaller tablet because the process of adjusting standard pharmaceutical excipients to achieve a target tablet size and weight was a routine and predictable formulation activity.

4. Key Claim Construction Positions

  • Petitioner stated it relied on the ordinary meaning of claim terms.
  • For the term "a pharmaceutically acceptable salt thereof," Petitioner adopted the specification's description that the amount of the salt is one that provides the desired amount of the free acid or base form of the compound.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued against discretionary denial under both 35 U.S.C. §325(d) and the Fintiv factors.
  • Under §325(d), Petitioner asserted that while the primary references in Ground 1 (WO '323 and WO '351) were before the examiner, they were not properly appreciated, evidenced by the examiner's erroneous conclusion that WO '323 only taught separate, not simultaneous, administration. For Grounds 2 and 3, the additional references were not before the examiner and presented new, non-cumulative arguments regarding salt selection and tablet formulation.
  • Regarding Fintiv, Petitioner contended that it presented compelling and meritorious challenges that, if unrebutted, would lead to a finding of unpatentability, meeting the standard to avoid denial.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-13 of the '802 patent as unpatentable.