Obviousness

Obviousness Analysis under 35 U.S.C. § 103 for US Patent 11066656

This analysis considers the obviousness of US patent 11066656 under 35 U.S.C. § 103, drawing upon the "Prior art keywords" provided in the Google Patents information and the patent's own background and definitions. The relevant prior art date is December 30, 2011.

A Person Having Ordinary Skill in the Art (POSA) in the field of protein engineering and pharmaceutical formulation, as of the priority date, would have knowledge of recombinant protein expression, mutagenesis techniques, and standard methods for assessing protein activity and stability. The POSA would also be aware of the challenges associated with the stability of therapeutic proteins and the need for improved formulations.

General Prior Art Landscape

The "Prior art keywords" associated with US11066656—"position corresponding," "polypeptide," "amino acid," "modified," and "seq"—indicate that the general concepts of polypeptides, their amino acid sequences, methods of modifying these sequences, and the idea of comparing amino acid positions across different sequences were well-established in the prior art.

The patent's own background explicitly states 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." It further acknowledges, "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." This last statement directly articulates a known problem and a motivation in the prior art to seek improved hyaluronidases, including those with enhanced stability.

Common protein denaturation conditions, such as "elevated temperature greater than 30° C. or about 30° C., agitation, low salt, including essentially or substantially or no salt, and presence of excipients that tend to denature proteins," were also recognized in the prior art as factors affecting protein stability. The patent further specifies "phenolic preservatives" as exemplary denaturing excipients.

Obviousness of Independent Claims

Independent Claim 1: Modified PH20 Polypeptide with Increased Stability

Claim 1: "A modified PH20 polypeptide that exhibits increased stability compared to a PH20 polypeptide not containing the amino acid replacement, wherein increased stability is manifested as increased resistance to denaturation in the presence of one or more protein denaturation conditions selected from the group consisting of: (a) elevated temperature greater than 30° C.; (b) agitation; (c) low salt of less than 100 mM; and (d) presence of an excipient; wherein the unmodified PH20 polypeptide consists of the sequence of amino acids set forth in SEQ ID NO: 7 or is a C-terminal truncated fragment thereof that is a soluble PH20 polypeptide or has at least 85% sequence identity thereto."

Obviousness Rationale:
A POSA, recognizing the therapeutic utility of PH20 hyaluronidase (as evidenced by commercially available forms mentioned in the patent) and the stated "need" for "Improved hyaluronan-degrading enzymes", would have been motivated to enhance the stability of known PH20 polypeptides, such as the human PH20 (SEQ ID NO: 7) or its soluble C-terminal truncated fragments. The general knowledge of protein modification, as indicated by "Prior art keywords" like "modified," "polypeptide," and "amino acid," would lead a POSA to explore amino acid replacements, deletions, or insertions to achieve such improvements.

The specific denaturation conditions listed in the claim—elevated temperature, agitation, low salt, and the presence of excipients (including preservatives)—were recognized challenges for protein formulations in the prior art. Improving stability under these conditions would be a routine and desirable goal for a therapeutic protein. The claim defines the invention by a result (increased stability) rather than a specific, non-obvious modification or an unexpected property. A POSA would have a reasonable expectation of success in identifying such modified polypeptides by applying routine protein engineering techniques and screening for stability under these well-known denaturing conditions.

Combination of Prior Art:

1. Known PH20 polypeptides: The unmodified PH20 polypeptide, specifically human PH20 (SEQ ID NO: 7) or its C-terminal truncated, soluble fragments, was known.
2. General Protein Engineering Techniques: The "prior art keywords" (modified, polypeptide, amino acid, seq, position corresponding) represent the widely known techniques of altering protein sequences to modify properties.
3. Motivation for Improved Stability: The patent itself identifies the "need" for "Improved hyaluronan-degrading enzymes", and improving stability under various denaturing conditions (temperature, salt, excipients, agitation) is a common and obvious objective for therapeutic proteins.
4. Known Denaturing Conditions: The listed conditions are explicitly described in the patent as "Exemplary protein denaturation (or denaturing, used interchangeably herein) conditions", indicating their recognition in the prior art.

A POSA would combine the known PH20 polypeptide (1) with general protein engineering techniques (2) to generate modified variants, driven by the motivation to address the known stability challenges for therapeutic enzymes (3). These variants would then be screened against the recognized denaturing conditions (4) to identify those with increased stability.

Independent Claim 25: Pharmaceutical Composition

Claim 25: "A pharmaceutical composition comprising the modified PH20 polypeptide of claim 1 and a pharmaceutically acceptable excipient."

Obviousness Rationale:
If the modified PH20 polypeptide of Claim 1 is considered obvious, then its inclusion in a pharmaceutical composition with "a pharmaceutically acceptable excipient" would also be obvious. The patent explicitly states the therapeutic uses of hyaluronidases, which inherently implies their formulation into pharmaceutical compositions. The selection of pharmaceutically acceptable excipients for protein drugs is a routine matter for a POSA in pharmaceutical formulation.

Combination of Prior Art:

1. The Modified PH20 Polypeptide of Claim 1: If considered obvious, this forms the active ingredient.
2. Known Pharmaceutical Formulations for Therapeutic Proteins: The prior art recognized that hyaluronidases were used therapeutically, meaning they were already formulated with excipients. General knowledge of formulating therapeutic proteins with "pharmaceutically acceptable excipients" is routine.

A POSA would readily combine an improved therapeutic protein (the modified PH20 of claim 1, if obvious) with standard pharmaceutical excipients to create a functional drug product, given the known therapeutic applications of hyaluronidases.

Independent Claim 30: Method for Identifying Stable Modified Hyaluronan-Degrading Enzyme

Claim 30: "A method for identifying or selecting a modified hyaluronan-degrading enzyme that exhibits stability under a denaturation condition, comprising the steps of: a) testing the activity of a modified hyaluronan-degrading enzyme in a composition containing a denaturing agent and/or under a denaturing condition; b) testing the activity of the modified hyaluronan-degrading enzyme in the same composition and/or under the same conditions as a) except absent the denaturing agent or condition; and c) selecting or identifying a modified hyaluronan-degrading enzyme that exhibits activity in a) that is at least 5% of the activity in b)."

Obviousness Rationale:
This claim describes a standard, routine, and logical method for assessing and selecting proteins for stability. The general concept of screening modified proteins for desired properties, including stability, was well-known in protein engineering. Comparing the activity of a protein under a stressful (denaturing) condition to its activity under a non-stressful condition is a fundamental and obvious experimental approach to quantify its resistance to denaturation. The 5% activity threshold for selection is an arbitrary but reasonable practical choice for a POSA aiming to identify enzymes retaining some level of activity under stress.

Combination of Prior Art:

1. General Protein Engineering Practice: The "prior art keywords" (modified, polypeptide) underpin the practice of generating modified proteins.
2. Known Methods for Assessing Protein Activity: The patent refers to "in vitro assays to determine the hyaluronidase activity" as known in the art.
3. Known Denaturing Conditions: The concept of "denaturing conditions" and "denaturing agents" was known in the prior art as factors affecting protein stability.
4. Standard Comparative Assays: The methodology of comparing protein performance under different conditions (stress vs. no stress) to evaluate properties like stability is a fundamental scientific principle.

A POSA would combine the knowledge of generating modified enzymes (1) with established assays for activity (2) and apply them to known denaturing conditions (3), using a standard comparative approach (4) to identify enzymes that demonstrate stability.

Independent Claim 31: Method for Identifying Modified Hyaluronan-Degrading Enzyme with Increased Stability

Claim 31: "A method for identifying or selecting a modified hyaluronan-degrading enzyme that exhibits increased stability under a denaturation condition, comprising the steps of: a) testing the activity of a modified hyaluronan-degrading enzyme in a composition containing a denaturing agent and/or under a denaturing condition; b) testing the activity of the corresponding unmodified hyaluronan-degrading enzyme in a composition containing the same denaturing agent and/or under the same denaturing condition as a), whereby the activity is tested under the same conditions as a); and c) selecting or identifying a modified hyaluronan-degrading enzyme that exhibits greater activity than the unmodified hyaluronan-degrading enzyme, thereby identifying or selecting a modified hyaluronan-degrading enzyme that exhibits increased stability under a denaturation condition."

Obviousness Rationale:
Similar to Claim 30, this claim outlines another fundamental and obvious method for screening for improved protein characteristics. When the goal is "increased stability," the most direct and logical approach for a POSA is to compare the performance of a modified protein to its unmodified counterpart under the very conditions where improvement is sought. This comparative testing directly measures the "increased" aspect of stability.

Combination of Prior Art:
The same elements as for Claim 30 apply, but with a specific focus on comparative testing against an unmodified baseline.

1. General Protein Engineering Practice: For generating modified enzymes.
2. Known Methods for Assessing Protein Activity: For measuring hyaluronidase activity.
3. Known Denaturing Conditions: The conditions under which stability is assessed.
4. Standard Comparative Experimental Design: The methodology of directly comparing a candidate variant to a control (the unmodified enzyme) under identical stressed conditions to ascertain improvement is a bedrock of scientific experimentation.

A POSA, tasked with finding an improved (more stable) enzyme, would naturally compare modified variants against the known unmodified enzyme (1) using known activity assays (2) under denaturing conditions (3) and select those showing superior performance (4).

Conclusion on Obviousness

Based on the explicit statements within US11066656 regarding the prior art context, particularly the "need" for "Improved hyaluronan-degrading enzymes," and the general knowledge of protein engineering as broadly indicated by the "Prior art keywords," all four independent claims appear obvious. The claims describe either known polypeptides modified to achieve a desirable and expected property (increased stability) using routine techniques, or routine methods for identifying such modified proteins. The patent does not appear to claim a specific non-obvious modification or an unexpected property resulting from a specific modification.