Obviousness

The analysis of US patent 12195773 under 35 U.S.C. § 103 requires identifying combinations of prior art references and explaining the motivation a person having ordinary skill in the art (POSA) would have to combine them. The PTAB has already instituted a Post-Grant Review (PGR2025-00053) for claims 1-28 of US12195773, specifically citing obviousness over US 2013/0183307 (Shepard '307) in view of various combinations with other prior art references from the "Shepard" family, including WO 2013/082729, WO 2014/194294, US 9,447,401, US 10,865,400, and US 11,041,149.

Scope and Content of the Prior Art

The "Shepard" prior art references are a family of patents and applications from the same inventors (Ge Wei, H. Michael Shepard, Qiping Zhao, Robert James Connor) that consistently address "PH20 polypeptide variants, formulations and uses thereof." These documents collectively disclose:

• Modified PH20 Polypeptides: The core concept across these references is the modification of PH20 hyaluronidase polypeptides, primarily through amino acid replacements, to alter their properties.
• Increased Stability: Specifically, the prior art details modified PH20 polypeptides exhibiting increased stability under various denaturing conditions. These conditions include elevated temperatures, agitation, low salt concentrations, and the presence of excipients such as phenolic preservatives. For example, US 9,447,401 and US 10,865,400 explicitly discuss increased stability to phenolic preservatives and stability at various temperatures (e.g., 0°C to 40°C, 30°C to 45°C). WO 2014/194294 focuses on "thermally stable PH20 hyaluronidase variants."
• Increased Activity: The prior art also consistently teaches modified PH20 polypeptides with increased hyaluronidase activity compared to unmodified PH20.
• Amino Acid Positions: The modifications are described as amino acid replacements at specific positions, often referenced to SEQ ID NO:3 of the human PH20 sequence.
• Formulations and Uses: The references broadly cover compositions and pharmaceutical formulations containing these modified PH20 polypeptides, as well as their therapeutic uses, including combination with other active agents like insulin, and methods for identifying such variants.

Differences Between the Prior Art and the Claims at Issue

The patent US12195773, as a continuation of earlier applications within the "Shepard" family, claims modified PH20 polypeptides with increased stability to phenolic preservatives (Claim 1), increased stability at elevated temperatures (Claim 18), and increased hyaluronidase activity (Claim 31), along with methods of production and pharmaceutical compositions. The differences are likely in the specific combinations of modifications, precise stability/activity thresholds, or the scope of claimed embodiments. However, the foundational concepts, general approaches, and even many specific examples of modifications leading to enhanced properties are extensively covered in the cited Shepard prior art.

Motivation to Combine Prior Art References

A person having ordinary skill in the art (POSA) in the field of protein engineering, particularly concerning therapeutic enzymes like hyaluronidase, would have been highly motivated to combine the teachings of the "Shepard" prior art references. This motivation arises from several key factors:

1. Shared Problem and Research Goal: All the "Shepard" references, including the primary reference US 2013/0183307, explicitly identify the common problem of needing "improved hyaluronan-degrading enzymes, such as hyaluronidases, and compositions containing such enzymes that can be used for treatment." The shared objective across these documents is to develop PH20 variants with "increased stability and/or increased activity" for pharmaceutical applications. This clearly articulated, consistent goal would naturally direct a POSA to consider the entire body of work from the same research group.

2. Analogous Art and Common Inventive Concepts: The references are all by the same inventors and constitute a patent family (evidenced by continuation and divisional relationships). This signals to a POSA that these documents represent a continuous and interrelated research effort. The core inventive concept—modifying PH20 through amino acid replacements to improve its stability and/or activity—is central to all these disclosures. A POSA would therefore view these documents not as disparate pieces of prior art, but as complementary parts of a comprehensive teaching on PH20 engineering.

3. Predictable Results and Expectation of Success: Given the consistent teaching of amino acid modifications leading to enhanced stability (e.g., thermal stability, stability in the presence of preservatives) and increased activity in the Shepard prior art, a POSA would have a reasonable expectation of success in combining the disclosed strategies and specific mutations to achieve further optimized PH20 variants. The prior art provides lists of positions and types of amino acid replacements that confer these beneficial properties. For instance, if one reference teaches a mutation for thermal stability and another for preservative stability, a POSA would be motivated to combine them to achieve a PH20 with both improved properties, particularly if the mutations are at different, non-interfering sites.

4. Specific Motivations for Claimed Features:

   • Increased Stability to Phenolic Preservatives (Claim 1): US 9,447,401 and US 10,865,400 explicitly address and disclose PH20 polypeptides with "increased stability to a phenolic preservative." A POSA developing a multi-dose pharmaceutical formulation (which typically requires preservatives) would be directly motivated to consult and combine the teachings from these references to create a PH20 variant that maintains activity in the presence of such agents.
   • Increased Stability at Elevated Temperatures (Claim 18): US 9,447,401 and WO 2014/194294 both focus on thermal stability and increased activity at elevated temperatures. A POSA designing a product for varied storage conditions or for administration in vivo would be motivated to combine these teachings to ensure the enzyme's robustness against temperature fluctuations.
   • Increased Hyaluronidase Activity (Claim 31): The pursuit of higher enzymatic activity is a common goal in enzyme engineering to reduce dosage or improve efficacy. Since all Shepard documents mention "increased activity" as a desired outcome of PH20 modification, a POSA would be motivated to select and combine known mutations from these references that contribute to or are expected to contribute to higher enzymatic activity.

In conclusion, the close relationship among the "Shepard" prior art references, their shared problem statement, common inventive concept, and specific disclosures regarding stability and activity enhancements for PH20 polypeptides, would have provided a strong motivation for a POSA to combine these teachings. This combination would lead to a reasonable expectation of successfully developing PH20 variants with the characteristics claimed in US patent 12195773, thereby rendering those claims obvious under 35 U.S.C. § 103.