PTAB

IPR2025-00621

REGenX Science Inc v. NextGen Biologics Inc

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Biomaterials for Xenotransplantation from Urodele Tissue
  • Brief Description: The ’376 patent discloses product-by-process claims for a biomaterial comprising a decellularized extracellular matrix (ECM) derived from a urodele (e.g., axolotl, salamander). The patent also covers methods of producing this biomaterial for xenograft purposes.

3. Grounds for Unpatentability

Ground 1: Claims 1-3, 5-6, 9, 13-16, 21, 24, and 26-32 are obvious over the combination of Badylak 2004, Badylak 2009, Freyman, McCusker, McGann, and Keating.

  • Prior Art Relied Upon: Badylak 2004 (a 2004 journal article), Badylak 2009 (a 2009 journal article), Freyman (WO 2009/089110), McCusker (a 2011 journal article), McGann (a 2001 journal article), and Keating (Application # US 2003/0212024).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the independent claims’ limitations—obtaining tissue comprising ECM from a urodele and decellularizing it to reduce antigenicity for xenograft use—were rendered obvious by the prior art. Badylak and Freyman established that by 2013, the use of decellularized xenogeneic ECM from a wide variety of animal sources (including mammals and amphibians, per Freyman) was a well-known, successful, and routine practice for tissue regeneration. These references taught standard decellularization processes (e.g., alkaline and detergent treatments) to remove cellular components and reduce immunogenicity while preserving the bioactive ECM structure, which was known to be highly conserved across species.
    • Motivation to Combine: Petitioner asserted that a Person of Ordinary Skill in the Art (POSA) would combine these teachings and select urodele as a source for a xenogeneic ECM. The motivation arose from the widely documented, exceptional regenerative capabilities of urodeles (axolotls and newts), as taught by McCusker, McGann, and Keating. These references established that urodele regenerative signaling pathways were conserved across species, including humans, and that extracts from urodele tissue could induce regenerative effects in mammalian cells. A POSA would have been motivated to apply the proven technology of xenogeneic ECM scaffolds to a source with such superior, well-understood regenerative properties to create an improved tissue graft.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success for several reasons. First, the success of all existing xenografts relied on the principle that ECM components are highly conserved across species. Second, decellularization was a routine and broadly applicable process known to work on tissues from diverse animal sources. Finally, McGann and Keating had already demonstrated that urodele-derived extracts successfully promoted regenerative responses in mammalian cells, confirming their cross-species bioactivity.

Ground 2: Claims 9-11 and 23 are obvious over the Ground 1 References in view of Gilbert 2005.

  • Prior Art Relied Upon: The references from Ground 1 and Gilbert 2005 (a 2005 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground builds on Ground 1 by addressing claims directed to powdered ECM with specific particle sizes. While the Ground 1 references taught processing ECM into various forms including powders (Freyman, Badylak 2009), Gilbert 2005 taught specific methods for producing ECM powders with controlled particle sizes. Gilbert disclosed producing powders with mean particle sizes of approximately 158 µm to 191 µm, which falls within the claimed ranges of 125-850 microns (claim 10) and less than 250 microns (claim 11). Gilbert also taught methods for homogenizing the ECM to create this powder, as required by claim 23.
    • Motivation to Combine: A POSITA would combine Gilbert’s teachings with the urodele-derived ECM of Ground 1 to achieve the known benefits of powdered ECM. Gilbert explicitly noted that powdered form provides greater flexibility for delivery and is suitable for minimally invasive injection, a clear advantage for clinical applications.
    • Expectation of Success: Success was predictable because Gilbert provided reproducible methods for creating ECM powders with the desired particle sizes and demonstrated their suitability for injection.

Ground 3: Claims 7-8, 12, 17-19, 22, and 25 are obvious over the Ground 1 References in view of Van Dyke.

  • Prior Art Relied Upon: The references from Ground 1 and Van Dyke (WO 2007/124127).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addresses claims requiring the addition of xenogeneic agents (e.g., growth factors, cells) to the ECM scaffold. Van Dyke, like Freyman, taught that ECM scaffolds could be enhanced by adding agents such as growth factors, antibiotics, and other proteins to improve performance. Critically, Van Dyke also explicitly taught modifying bioscaffolds to allow for seeding with mammalian cells, including human cells, to enhance tissue integration (claims 7 and 8). Furthermore, Van Dyke disclosed packaging the final bioscaffold in a sterile container for subsequent use (claim 12).
    • Motivation to Combine: A POSITA would be motivated to add the agents taught by Van Dyke to the urodele ECM scaffold to achieve well-understood benefits. Adding growth factors was known to enhance regenerative potential, antimicrobials to prevent infection, and human cells to repair larger or more complex defects. These were common strategies to optimize ECM grafts.
    • Expectation of Success: A POSITA would expect success, as incorporating such additives and seeding cells were established techniques routinely and successfully applied to other xenogeneic ECM scaffolds to improve their therapeutic effect.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under 35 U.S.C. §325(d) is unwarranted because the primary prior art references asserted in all grounds were never substantively considered by the Examiner during prosecution. Although Van Dyke was submitted in an Information Disclosure Statement, it was not applied in any rejection.
  • Petitioner further argued that discretionary denial under 35 U.S.C. §314(a) based on the Fintiv factors is inappropriate because there are no parallel district court or other proceedings involving the ’376 patent.

5. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 1-3, 5-19, and 21-32 of the ’376 patent as unpatentable.