Obviousness

Obviousness Analysis under 35 U.S.C. § 103 for US Patent 11,041,149

This analysis identifies combinations of prior art references that would render the independent claims of US Patent 11,041,149 obvious to a person having ordinary skill in the art (PHOSITA) as of the patent's priority date of December 30, 2011. The underlying motivation for these combinations stems from known problems in therapeutic protein formulation and the well-established field of protein engineering.

Background and Motivation for Improvement

The patent itself acknowledges the existing therapeutic use of hyaluronidases and a need for improved enzymes. Specifically, it notes that "hyaluronidases have been used therapeutically (e.g., hyaluronidases sold under the trademarks Hydase® (bovine testicular hyaluronidase), Vitrase® (ovine hyaluronidase), and Wydase® (bovine hyaluronidase)), typically as dispersing and spreading agents in combination with other therapeutic agents." [patent text] It further states, "Many of these are ovine or bovine forms, which can be immunogenic for treatment of humans. Improved hyaluronan-degrading enzymes, such as hyaluronidases, and compositions thereof that can be used for treatment are needed." [patent text] This explicitly establishes the motivation for a PHOSITA to develop human or humanized hyaluronidases with improved properties, such as increased stability and activity, to overcome immunogenicity and enhance therapeutic utility.

The sequences of human PH20 (full-length, e.g., SEQ ID NO:7, and soluble C-terminal truncated forms, e.g., SEQ ID NO:3), which serve as the "unmodified PH20 polypeptide" [patent text, cite: 5], were known and considered prior art.

Combination 1: For Independent Claim 1 (Modified PH20 with increased general stability)

Claim 1 covers a modified PH20 polypeptide with increased stability (resistance to denaturation under conditions like high temperature, agitation, low salt, or certain excipients), retaining hyaluronidase activity, and optionally glycosylated, compared to an unmodified PH20 polypeptide (e.g., SEQ ID NO:7 or 3).

Prior Art Combination:

1. Known Human PH20 Polypeptide: The unmodified human PH20 polypeptide, as defined in the patent (e.g., SEQ ID NO:3 or 7), serves as the foundational prior art [patent text, cite: 5]. Its function as a hyaluronan-degrading enzyme and its therapeutic potential were well-understood. The patent itself identifies the core hyaluronidase domain and notes prior art literature identifying the GPI-anchor attachment signal sequence, indicating knowledge of its structure.
2. General Protein Engineering for Stability: US Patent 6,385,546 B1 (granted May 7, 2002) describes a method for identifying and changing amino acid residues to "adjust" the stability of a protein under particular conditions, such as higher temperatures or in the presence of co-solvents or co-solutes, without affecting its active site. This patent explicitly states that the method has wide applicability, including to enzymes.
3. Methods for Identifying Stabilizing Mutations: WO 2009/095235 A1 (published August 6, 2009) discloses methods involving mutagenesis to generate mutant libraries. These libraries can be screened to study the role of specific amino acids in protein stability and function, and to develop new or stabilized proteins, including enzymes. It also suggests that appropriate mutants may be combined for further optimization. General protein engineering techniques like directed evolution and site-directed mutagenesis were well-established by the priority date for enhancing enzyme stability. Assays to determine hyaluronidase activity were also "known in the art" [patent text].

Motivation to Combine:
A PHOSITA, faced with the recognized need for improved, stable human hyaluronidases (due to the immunogenicity of non-human forms and the general desirability of stable therapeutic proteins for extended shelf-life and robust handling) [patent text], would be motivated to apply well-known protein engineering techniques to the known human PH20 sequence. The teachings of US 6,385,546 B1 would guide the PHOSITA to systematically identify and alter amino acid residues to increase stability, including resistance to elevated temperatures and other denaturing conditions. The methodology detailed in WO 2009/095235 A1 (generating mutant libraries and screening for stability) would provide a clear path to discover specific amino acid replacements that achieve the desired increased stability. Given the known principles of protein folding and stability, a PHOSITA would have a reasonable expectation of success in finding such stabilizing mutations through routine experimentation (e.g., saturation mutagenesis at selected sites or even random mutagenesis followed by screening).

Combination 2: For Independent Claim 13 (Modified PH20 with increased stability to phenolic preservative)

Claim 13 focuses on a modified PH20 polypeptide exhibiting increased stability specifically in the presence of a phenolic preservative, achieved via amino acid replacement.

Prior Art Combination:

1. Known Human PH20 Polypeptide: As in Combination 1, the unmodified human PH20 polypeptide (e.g., SEQ ID NO:3 or 7) is known prior art [patent text, cite: 5].
2. General Protein Engineering for Excipient Stability: US Patent 6,385,546 B1, as cited above, broadly covers adjusting protein stability in the "presence of co-solvents or co-solutes". Phenolic preservatives fall within the category of co-solutes that can impact protein stability in pharmaceutical formulations.
3. Knowledge of Preservative Effects: By 2011, it was general knowledge in pharmaceutical formulation that phenolic preservatives (such as phenol, m-cresol, benzyl alcohol, and parabens, all explicitly mentioned in the patent) are used in multi-dose drug formulations but can also pose stability challenges for protein therapeutics. The patent itself lists "presence of excipients that can be denaturing (e.g., phenolic preservatives or detergent)" as an "exemplary protein denaturation condition" [patent text], confirming this as common knowledge.
4. Need for Stable Formulations with Other Biologics: WO 2011/034604 A2 (published March 24, 2011) describes stable co-formulations of hyaluronidase with immunoglobulins. While not insulin, this patent explicitly demonstrates the recognized need for stable hyaluronidase formulations when combined with other active agents, a context where preservatives are commonly employed and present stability challenges.

Motivation to Combine:
A PHOSITA involved in developing therapeutic protein formulations, and aware of the general need for stable hyaluronidases in pharmaceutical compositions, would recognize the challenge posed by phenolic preservatives to protein stability. Given the teachings of US 6,385,546 B1 regarding modifying protein residues for stability in the presence of co-solutes, and the established methods for screening protein libraries for desired properties (WO 2009/095235 A1), it would be obvious to apply these techniques to human PH20 to identify specific amino acid replacements that confer increased stability in the presence of phenolic preservatives. This would be an "obvious to try" endeavor, aiming to solve a known problem (preservative-induced instability) using known methods (protein engineering/screening) on a known protein (human PH20) for a desired and predictable outcome (more stable formulation).

Combination 3: For Independent Claim 16 (Pharmaceutical composition with modified PH20 and insulin)

Claim 16 describes a pharmaceutical composition containing a modified PH20 polypeptide with increased stability to a phenolic preservative (as in Claim 13) and an insulin (e.g., fast-acting insulin), along with other optional excipients.

Prior Art Combination:

1. Known Co-Formulation of Hyaluronidase and Insulin: It was well-known prior to 2011 that hyaluronidases were used as "dispersing and spreading agents in combination with other therapeutic agents," including insulin, to enhance absorption [patent text, cite: 11, 13]. US Patent 7,767,429 B2 (granted August 3, 2010) specifically teaches administering soluble hyaluronidase "simultaneously with or following administration of other therapeutic molecules," with insulin explicitly mentioned as an example of a fluid that can be formulated.
2. Modified PH20 with Preservative Stability: The modified PH20 polypeptide of Claim 13 (which, as argued above, would have been obvious).
3. Standard Pharmaceutical Formulation Practice: The use of insulin in pharmaceutical compositions, including with various excipients, buffers, and preservatives, was standard practice. The patent itself details such common components [patent text].

Motivation to Combine:
Since co-formulation or co-administration of hyaluronidase with insulin was a known therapeutic strategy to improve insulin absorption [patent text, cite: 11], a PHOSITA would be motivated to use an improved, more stable hyaluronidase in such a composition. If the modified PH20 with increased stability to phenolic preservatives (as described in Claim 13) was obvious, then combining this improved enzyme with insulin in a pharmaceutical composition would also be obvious. The motivation would be to create a more robust, stable, and potentially multi-dose formulation of insulin with enhanced absorption properties, overcoming the stability issues that often arise when proteins are formulated with preservatives. This represents an obvious combination of known elements to improve a known product (hyaluronidase-insulin formulation) in a predictable way (enhanced stability).

Combination 4: For Independent Claims 19 & 22 (Methods for identifying/selecting modified hyaluronan-degrading enzymes for stability)

Claim 19 describes a method for identifying a modified hyaluronan-degrading enzyme with stability under denaturing conditions by comparing its activity in the presence and absence of the denaturing condition. Claim 22 describes a similar method, comparing the modified enzyme's activity in a denaturing condition to that of a corresponding unmodified enzyme under the same denaturing condition.

Prior Art Combination:

1. Known Hyaluronan-Degrading Enzymes: Hyaluronan-degrading enzymes, particularly PH20, were known, as were their sequences and therapeutic uses [patent text, cite: 5]. The desire to improve their properties was also established [patent text].
2. Established Protein Engineering Methodologies: As discussed for Claim 1, US Patent 6,385,546 B1 teaches methods for identifying and changing amino acid residues to adjust protein stability. WO 2009/095235 A1 details generating mutant libraries and screening for stability and function.
3. Known Assays for Activity and Stability: The patent explicitly states that "In vitro assays to determine the hyaluronidase activity of hyaluronidases, such as PH20, including modified PH20 polypeptides, are known in the art and described herein" [patent text]. Methods for assessing protein stability (e.g., measuring activity retention under stress, monitoring aggregation) were routine in protein biochemistry and drug development by 2011. The concept of comparing activity under denaturing conditions to non-denaturing conditions, or to an unmodified control, is a fundamental aspect of protein stability screening.

Motivation to Combine:
A PHOSITA seeking to improve the stability of hyaluronan-degrading enzymes would naturally turn to established protein engineering and screening methodologies. The methods outlined in Claims 19 and 22 are direct applications of known techniques for directed evolution and rational protein design. Systematically introducing mutations into a known enzyme (human PH20) and then screening those variants for enhanced stability under relevant denaturing conditions (e.g., elevated temperature, low salt, or presence of excipients/preservatives) using known activity assays would be an obvious approach. The expectation of finding at least some stabilizing mutations through such a screening process, particularly by iterating the process as suggested by general protein engineering principles, would be reasonable for a PHOSITA.