PTAB

IPR2021-00857

Spectrum Solutions LLC v. Longhorn Vaccines & Diagnostics LLC

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Nucleic Acid Preservation Solutions and Methods
  • Brief Description: The ’399 patent is directed to aqueous stock solutions and methods for preserving and stabilizing nucleic acids in biological samples. The core invention claimed is a one-step solution comprising five reagent classes (chaotrope, detergent, reducing agent, chelator, buffer) sufficient to denature proteins, inactivate nucleases, kill pathogens, and prevent nucleic acid degradation without requiring refrigeration.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1, 4, 6, 8, 10-11, 16, 21-30, 32, and 35 under 35 U.S.C. §102 over Birnboim

  • Prior Art Relied Upon: Birnboim (Application # 2004/0038269).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Birnboim, which teaches compositions for stabilizing nucleic acids in saliva at room temperature, anticipates the challenged claims. Specifically, Petitioner asserted that Example 3 of Birnboim discloses a "nucleic acid-preserving solution" that meets every limitation of independent claim 1. This solution is an aqueous composition containing urea (a chaotrope), sodium dodecyl sulfate (a detergent), sodium ascorbate (a reducing agent), CDTA (a chelator), and TRIS-HCl (a buffer). Petitioner further contended that Birnboim explicitly teaches this solution performs the functional requirements of claim 1: denaturing proteins, inactivating nucleases, killing microbes, and preserving nucleic acids without degradation, as confirmed by subsequent examples showing DNA stability for up to 62 days. For dependent claims, Petitioner mapped Birnboim's disclosures to the specific reagents (e.g., SDS in claim 6, Tris in claim 8), concentrations (e.g., claim 4), and methods of use (e.g., claims 21-30) recited.

Ground 2: Obviousness of Claims 18-20 under 35 U.S.C. §103 over Birnboim in view of Das, Chen, and Wangh

  • Prior Art Relied Upon: Birnboim (Application # 2004/0038269), Das (Application # 2005/0123928), Chen (Application # 2007/0202511), and Wangh (WO 2004/104181).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that claims 18-20, which recite stock solutions with specific reagents at specific concentrations, would have been obvious. Birnboim was asserted to provide the basic five-component framework for a nucleic acid preservation solution. The secondary references, all within the same field, were argued to supply the remaining specific components and concentrations. For example, Das and Chen were cited for their disclosure of guanidinium thiocyanate and TCEP within the claimed concentration ranges. Wangh was cited for disclosing 10mM sodium citrate, and Das was cited for disclosing EDTA concentrations and Tris buffer concentrations that meet the claim limitations.
    • Motivation to Combine: A POSITA would combine these references as a matter of routine optimization. All references address the same problem of nucleic acid isolation and preservation using analogous compositions. Petitioner contended that a POSITA would have looked to references like Das, Chen, and Wangh to find known, effective concentrations and alternative reagents (like TCEP) to implement in a foundational solution like that disclosed by Birnboim.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because the combination involves using well-known reagents at established concentrations for their predictable functions. The combination merely required selecting from a small number of known options to optimize a standard preservation buffer, which would predictably result in a stable and effective solution.

  • Additional Grounds: Petitioner asserted numerous additional obviousness challenges. These included obviousness of all claims over Birnboim alone (Ground 2), arguing the combination of known elements yielded predictable results. Other grounds combined Birnboim with single secondary references to teach specific limitations, such as Chen for the reducing agent in claim 3, Reed for the surfactant in claim 9, Mori for the defoaming agent in claim 15, and Koller for demonstrating high preservation efficacy for claim 31.

4. Key Claim Construction Positions

  • "stock solution": Petitioner proposed this term be construed according to its plain and ordinary meaning as "a formulated supply of solution for future use." This construction was argued to be critical because it establishes that the claimed composition exists before being mixed with a biological sample. This interpretation is supported by claim language stating the "stock composition, when diluted with a sample..." performs certain functions, clearly distinguishing the initial solution from the final mixture.

5. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1-35 of the ’399 patent as unpatentable.