PTAB

IPR2025-00621

RegenX Science Inc. v. NeXtGen Biologics, Inc.

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1. Case Identification

2. Patent Overview

  • Title: Biomaterials for Xenotransplantation
  • Brief Description: The ’376 patent is directed to product-by-process claims for a decellularized extracellular matrix (ECM) derived from urodele (e.g., salamander, axolotl) tissue. The patent also covers biomaterials and methods of making biomaterials comprising this urodele-derived ECM for use in xenotransplantation.

3. Grounds for Unpatentability

Ground 1: Obviousness over Core Regenerative Medicine References - Claims 1-3, 5-6, 9, 13-16, 21, 24, and 26-32 are obvious over Badylak 2004, Badylak 2009, Freyman, McCusker, McGann, and Keating.

  • Prior Art Relied Upon: Badylak 2004, Badylak 2009, Freyman (WO 2009/089110), McCusker, McGann, and Keating (US 2003/0212024).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the independent claims (1, 31, 32) are obvious because the prior art established that xenogeneic ECM from a wide variety of animal sources (e.g., porcine, bovine) was routinely used for tissue regeneration in humans. Freyman and Badylak taught obtaining animal tissue and subjecting it to well-known decellularization processes to remove cellular components and reduce immunogenicity, making it suitable as a xenograft. Freyman explicitly disclosed that suitable animal sources include amphibians. Separately, McCusker, McGann, and Keating taught that urodeles (axolotls and newts) possess remarkable regenerative capabilities due to signaling pathways that are conserved across species, including humans, and that extracts from these animals could induce regenerative processes in mammalian cells.
    • Motivation to Combine (for §103 grounds): A person of ordinary skill in the art (POSITA) would have been motivated to substitute a known xenogeneic ECM source (e.g., porcine) with a urodele source. The motivation was to combine the established benefits and techniques of ECM scaffolds with the known, superior regenerative properties of urodeles to create a more effective biomaterial, which amounted to a predictable substitution of one known element for another.
    • Expectation of Success (for §103 grounds): A POSITA would have had a reasonable expectation of success because the prior art demonstrated that decellularization processes were broadly applicable across diverse species and that the fundamental components of ECM and regenerative signaling pathways were highly conserved, ensuring the urodele-derived ECM would be biocompatible and effective.

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

  • Prior Art Relied Upon: Ground 1 references and Gilbert 2005.
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground focused on dependent claims reciting an ECM powder with specific particle sizes (claims 10-11) and the process of homogenization (claim 23). Petitioner asserted that Gilbert 2005 taught specific methods for producing ECM powder with a controlled mean particle size (e.g., 158.0 µm and 190.6 µm), which falls squarely within the range of less than 250 microns required by the claims. The methods described in Gilbert for producing this particulate form, such as lyophilizing and grinding, directly teach the claimed homogenization.
    • Motivation to Combine (for §103 grounds): A POSITA would combine the urodele ECM of Ground 1 with the powder processing techniques of Gilbert 2005 to gain the known advantages of powdered ECM, such as improved flexibility for delivery and suitability for minimally invasive injection.
    • Expectation of Success (for §103 grounds): Success was expected as Gilbert's methods were described for ECM generally and had been successfully used to create injectable powders, a desired and predictable outcome.

Ground 3: Obviousness over Core References and Van Dyke - 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: Ground 1 references and Van Dyke (WO 2007/124127).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed claims requiring the ECM to be combined with xenogeneic agents such as growth factors, human cells, or antimicrobial agents. Van Dyke taught methods for producing bioscaffolds from various animal tissues, including amphibians, and explicitly disclosed that additives like growth factors (e.g., TGFβ), antibiotics, and cells (e.g., human cells) could be added to the bioscaffold to enhance its properties, such as by seeding the scaffold with a patient's own cells. Van Dyke also taught packaging the final bioscaffold in a sterile container.
    • Motivation to Combine (for §103 grounds): A POSITA would be motivated to add the agents taught by Van Dyke to the urodele ECM from Ground 1 for their well-understood benefits: enhancing regenerative potential (growth factors), preventing infection (antimicrobials), and improving repair of large defects (cell seeding).
    • Expectation of Success (for §103 grounds): A POSITA would expect success because the routine incorporation of such additives into other ECM xenografts was well-established and had proven effective.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under §325(d) is unwarranted because the primary references asserted in the petition (e.g., Badylak, Freyman, McCusker, McGann, Keating, Gilbert) were never considered by the Examiner during prosecution. While Van Dyke was cited in an Information Disclosure Statement (IDS), it was never substantively evaluated in an office action. Therefore, the art and arguments are new and not cumulative.
  • Petitioner also argued that denial under §314(a) based on Fintiv factors is inappropriate because there are no parallel district court proceedings involving the ’376 patent.

5. Relief Requested

  • Petitioner requested 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.