PTAB

IPR2018-00602

Merck Sharp & Dohme Corp v. Microspherix LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Imageable, Implantable Drug-Eluting Seed
  • Brief Description: The ’835 patent discloses an implantable "seed" for applications such as brachytherapy. The seed is designed to contain a therapeutic, prophylactic, or diagnostic agent and incorporates a marker component, such as a radiopaque medium, to allow for its visualization and positioning within a patient’s body.

3. Grounds for Unpatentability

Ground 1: Anticipation by Zamora - Claims 1-4, 9-12, and 15-19 are anticipated by Zamora under 35 U.S.C. §102.

  • Prior Art Relied Upon: Zamora (Patent 6,575,888).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Zamora discloses every element of the challenged claims. Zamora teaches a bioabsorbable brachytherapy device comprising a tubular polymeric housing that encloses a radioactive material and may further include therapeutic drugs and a radiopaque medium. Petitioner asserted this maps directly to the claimed "seed" having a "substantially continuous wall" (the housing) bounding a "hollow interior" that contains an "agent" (the therapeutic drug) and a "marker component" (the radiopaque medium). Zamora also discloses that its tubular housing may be a "tube or tube-like structure with at least one end," which Petitioner argued teaches the claimed "opening adapted to allow the agent to pass out."
    • Key Aspects: Petitioner contended that Zamora’s disclosure of a device with dimensions of 0.8 mm x 4.5 mm is precisely what the ’835 patent describes as a preferred embodiment, further demonstrating anticipation.

Ground 2: Obviousness over Zamora and Brem - Claims 1-4, 9-12, and 14-20 are obvious over Zamora in view of Brem.

  • Prior Art Relied Upon: Zamora (Patent 6,575,888) and Brem (Patent 5,626,862).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that to the extent Zamora does not anticipate every limitation, the combination with Brem renders the claims obvious. Specifically for claim 14, Brem teaches that a therapeutic agent is released from a polymer implant "by diffusion through the polymer’s micropore lattice." Petitioner contended this explicitly supplies the "plurality of pores" limitation for drug release, which may not be explicit in Zamora.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Zamora and Brem because both relate to implantable polymer devices for cancer treatment. A POSITA would be motivated to incorporate Zamora’s teaching of a radiopaque marker into Brem’s reservoir-style implant to gain the known benefit of tracking the implant's location. Concurrently, a POSITA would incorporate Brem's diffusion-based release mechanism into Zamora's device to achieve a more predictable, near-constant drug release rate.
    • Expectation of Success: A POSITA would have a high expectation of success in combining these references due to their significant technical overlap. Both teach implantable polymer devices for localized drug delivery in cancer therapy, and the use of radiopaque markers was a well-known solution to a common problem.

Ground 3: Obviousness over De Nijs and Schopflin - Claims 1-4, 10, 14, 16-17, and 20 are obvious over De Nijs in view of Schopflin.

  • Prior Art Relied Upon: De Nijs (Patent 5,150,718) and Schopflin (Patent 4,012,497).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was presented based on the Patent Owner's assertion in co-pending litigation that the ’835 patent covers contraceptive implants. De Nijs teaches a contraceptive implant with a core material containing a hormone, encased by a polymer membrane, which Petitioner mapped to the claimed "hollow interior" and "continuous wall." However, De Nijs does not explicitly teach an imageable marker. Schopflin remedies this by teaching the addition of a "radiopaque amount of barium sulfate" to polymer implants for "improved X-ray localization," thus supplying the "marker component" limitation. For claims 14 and 20, Petitioner argued that the ethylene-vinyl acetate (EVA) polymer used in De Nijs is inherently porous, allowing drug diffusion and thus satisfying the "plurality of pores/openings" limitation.
    • Motivation to Combine: A POSITA would combine these references as they are both directed to polymer implants for contraceptive hormone delivery. It would have been obvious to add the known safety feature from Schopflin (a radiopaque marker) to the non-biodegradable implant of De Nijs to solve the known problem of locating the implant for its eventual removal.
    • Expectation of Success: Success was expected because the references disclose heavily overlapping features, including cylindrical implants of similar dimensions (1.5-2 mm diameter, 1-4 cm length), the use of contraceptive hormones, and polymeric coatings.
  • Additional Grounds: Petitioner asserted an additional obviousness challenge against claims 14 and 20 based on De Nijs and Schopflin in further view of Brem, arguing that Brem reinforces the POSITA's understanding that the EVA polymer taught by De Nijs is inherently porous and releases drugs via diffusion through a "micropore lattice."

4. Key Claim Construction Positions

  • "Seed": For the purposes of the inter partes review (IPR), Petitioner proposed that the term "seed," recited in the preamble of all challenged claims, should be construed as "an implant that has a size and shape suitable for passing through a needle." This construction includes a cylinder or rod structure with a diameter between 0.8 to 3 mm and a length up to 40 mm. Petitioner based this on the patent’s specification and noted that the Patent Owner had adopted this interpretation in related district court litigation.

5. Relief Requested

  • Petitioner requests institution of an IPR and cancellation of claims 1-4, 9-12, and 14-20 of the ’835 patent as unpatentable under 35 U.S.C. §§ 102 and 103.