Patent: 8,431,124

Summary for Patent: 8,431,124

Title:	Methods for treating a disease characterized by an excess of hyaluronan by administering a soluble hyaluronidase glycoprotein (sHASEGP)
Abstract:	Provided are soluble neutral active Hyaluronidase Glycoproteins (sHASEGP\'s), methods of manufacture, and their use to facilitate administration of other molecules or to alleviate glycosaminoglycan associated pathologies. Minimally active polypeptide domains of the soluble, neutral active sHASEGP domains are described that include asparagine-linked sugar moieties required for a functional neutral active hyaluronidase domain. Included are modified amino-terminal leader peptides that enhance secretion of sHASEGP. Sialated and pegylated forms of the sHASEGPs also are provided. Methods of treatment by administering sHASEGPs and modified forms thereof also are provided.
Inventor(s):	Bookbinder; Louis H. (San Diego, CA), Kundu; Anirban (San Diego, CA), Frost; Gregory I. (Del Mar, CA)
Assignee:	Halozyme, Inc. (San Diego, CA)
Application Number:	12/386,473
Patent Claims:	see list of patent claims

United States Patent 8,431,124: Claim-by-Claim Strength, Claim Scope, and US Landscape

What does US 8,431,124 claim, in operational terms?

US 8,431,124 claims treatment methods that use a neutral-active hyaluronidase glycoprotein with covalent sugar moieties (at least one sugar moiety) attached to an asparagine residue, where the active protein is defined by specific amino-acid region(s) drawn from SEQ ID NO:1 (positions 36-477 through 36-483, and related identity/truncation rules). The treatment is defined by the presence of excess hyaluronidase substrate in diseased tissue versus normal tissue, and the patent includes a specific herniated disk chemonucleolysis use case plus spinal/scar embodiments.

Claim 1 is the independent “core” method claim

Claim 1 elements (must all be met):

• Patient condition: disease/condition with excess substrate for hyaluronidase versus normal tissue
• Treatment: administer a hyaluronidase glycoprotein to reduce the substrate amount in diseased tissue
• Substrate definition: “excess substrate” means increased accumulation in diseased tissue vs normal
• Glycoprotein structure:
  • at least one sugar moiety covalently attached to an asparagine residue
  • neutral active
• Protein identity definition:
  • glycoprotein is one of the enumerated sequence windows:
    • AA 36-477, 36-478, 36-479, 36-480, 36-481, 36-482, or 36-483 of SEQ ID NO:1, or
  • glycoprotein has AA substitutions in those windows but the resulting protein must have ≥95% AA sequence identity to one of those reference windows

Claim 2 narrows substrate origin and target indication

• substrate produced/accumulates in lumbar spine
• substrate causes intradiscal pressure of a herniated disk
• reducing substrate treats the herniated disk

Claims 3, 4, 7, 17 specify manufacturing

They claim producing and secreting the glycoprotein in a mammalian expression system using an expression vector with specified polynucleotide ranges:

• SEQ ID NO:6 nucleotides 106-1446 (or degenerates)
• or SEQ ID NO:48 inserted between flanking sequences
• Secreted glycoprotein recovery
• CHO cell is explicitly mentioned (claim 7)

Claims 5 and 6 reinforce protein definition

• claim 5: glycoprotein consists of one of the enumerated sequences (AA 36-477 through 36-483)
• claim 6: substitutions allowed but ≥95% identity maintained

Claims 8 and 9-12 cover compositions and conjugation

• claim 8: administer a composition comprising the specific glycoprotein (AA 36-482 window)
• claim 9: glycoprotein conjugated to a polymer
• claim 10: polymer is PEG or dextran
• claim 11-12 repeat for claim 8/11 as dependent structure

Claims 13-16 cover scar/substrate sources and additional spinal indications

• claim 13: excess substrate produced from scar tissue
• claim 14: scar tissue includes glial scar (spinal cord injury), surgical scar, or keloid
• claim 15-16 mirror claim 5-6 but in the scar/disk context

Claim 19 provides the chemonucleolysis framing

• Treat herniated disk by chemonucleolysis
• Contact the herniated disk with the glycoprotein amount sufficient to effect chemonucleolysis
• Requires the same glycoprotein structure and identity constraints as claim 1

Claim 20 expands truncation/identity flexibility

Claim 20 is an alternate independent method claim that adds a more detailed protein definition framework:

• glycoprotein contains sugar on asparagine and is neutral active
• glycoprotein is defined by one of multiple options:
  • (a) C-terminally truncated polypeptide: includes AA 36-464 with truncation at residues 477-483
  • (b) amino-acid substitutions in (a) while maintaining ≥95% AA identity to the reference
  • (c) >99% sequence identity
  • (d) >97% identity with (a) when truncation is at residue 483
• disease/condition remains defined by excess hyaluronidase substrate in diseased tissue vs normal

Claim 21 ties disease/condition to scar or herniated disk

Dependent limitation.

---

Where is the claim scope strongest (and what makes it enforceable)?

The patent’s defensibility is strongest where claim terms are both narrowly anchored to a defined protein and functionally tied to substrate accumulation.

1) Protein definition is specific, not generic “hyaluronidase”

The claims do not read on “any hyaluronidase.” They require:

• neutral-active hyaluronidase glycoprotein
• glycoprotein has covalent sugar moieties on asparagine
• amino-acid identity requirements anchored to specific SEQ ID NO:1 regions (AA 36-477 through 36-483) and/or defined C-terminal truncation rules and sequence identity thresholds (≥95% AA identity; plus tighter >99% and >97% paths in claim 20)

This architecture reduces the risk that earlier hyaluronidase disclosures (non-neutral, non-glycosylated, different isoforms, different sequence regions) automatically anticipate.

2) The glycosylation anchor is a functional structural requirement

“Sugar moiety covalently attached to an asparagine residue” is a structural constraint that can distinguish from:

• non-glycosylated recombinant constructs
• different glycosylation patterns
• hyaluronidase proteins without the specified N-linked glycosylation at an asparagine residue (depending on how “sugar moiety” and “asparagine residue” are implemented in the specification and how courts interpret the claim language).

3) Use limitation is anchored to excess substrate accumulation

The methods require a condition “characterized by excess substrate for hyaluronidase,” defined as:

• increased accumulation in diseased tissue compared to normal tissue
• treatment aims to reduce that accumulation

This helps distinguish from uses that do not establish substrate excess (or do not rely on substrate reduction as the mechanism).

---

What are the highest-risk weaknesses in claim construction?

The risk is not “lack of concept.” It is in terms that may be construed broadly, or in proof issues that become litigation pressure points.

1) “Neutral active” can be litigated as a lab-defined property

If prior art hyaluronidases show neutral activity under some assay conditions, “neutral active” can become a factual question. The claims do not define:

• assay conditions
• pH range threshold
• activity metric

That can weaken the practical narrowing if the prior art can be mapped to “neutral active” conditions.

2) Identity thresholds (≥95%, >97%, >99%) create a boundary line that invite “design-around”

The claims include multiple identity standards:

• 95% identity to specified windows (claims 1, 6, 16)
• 99%+ identity in claim 20(c)
• 97%+ identity when truncation is at residue 483 in claim 20(d)

These thresholds are enforceable but create a “just-below-threshold” strategy:

• competitor proteins engineered to sit below the identity cutline and still be neutral-active and glycosylated in a functionally similar way.

Litigation focus often shifts to how identity is calculated (alignment method, gap penalties, whether conservative substitutions count, and how truncations are handled).

3) Truncation at residue 477-483 is specific, but the claim language allows flexibility

Claim 20’s options (a)-(d) allow variants built from:

• a truncated backbone including at least AA 36-464, with truncation at residues 477-483
• plus substitutions within that framework

This broadens coverage relative to claim 1, but it can also make validity harder if prior art shows closely related truncations and conservative substitutions.

4) Polymer conjugates (PEG/dextran) are limited but still broad

Claims 9-12 do not specify:

• PEG chain length or attachment chemistry
• degree of substitution (DS)
• linker composition
• whether the sugar attachment on asparagine remains intact after conjugation

If prior art uses PEGylated hyaluronidase generally, novelty could be challenged unless the patent ties PEGylation to the specific glycoprotein sequences and neutral/glycosylation constraints.

---

How do the dependent claims map to likely competitive products?

A credible competitive landscape assessment depends on whether market competitors use:

1. native-like glycoprotein hyaluronidase with N-linked glycosylation
2. neutral-active isoforms
3. specific C-terminal truncations around residues 477-483
4. mammalian secretion (CHO) expression vectors matching SEQ ID NO scaffolds
5. polymer conjugation (PEG/dextran)

Likely “hit” zones for licensing or enforcement

• Products marketed for chemonucleolysis or herniated disk treatment using hyaluronidase-like biologics where the protein is defined by C-terminal windows around 36-477 to 36-483 and neutral activity.
• Scar-related indications where excess substrate accumulation is argued and neutral glycoprotein is administered.

Likely “miss” or “evade” zones

• Products using acid-active hyaluronidases (different enzyme activity profile).
• Products using recombinant hyaluronidase constructs that are not glycosylated on asparagine as required by the claim.
• Products using different protein regions outside the claimed AA windows and truncation scheme.
• Products that emphasize mechanistic substitution (e.g., hyaluronate-targeting agents) without meeting the claim’s neutral-active glycoprotein identity rules.

---

What does the patent landscape risk look like without full prosecution history?

Only the claim set was provided. That limits precise analysis of:

• novelty defenses
• the allowed scope during prosecution
• claim amendments that may clarify “neutral active” or identity calculations
• whether US 8,431,124 is part of a continuation chain that already narrowed/expanded claim language

Under a strict claims-only read, the landscape risk splits into two categories: (i) validity (anticipation/obviousness) and (ii) non-infringement (protein does not meet sequence/identity/glycosylation/truncation constraints).

Given the architecture, validity challenges will most likely focus on:

• whether earlier disclosures already describe a neutral-active, asparagine-glycosylated hyaluronidase with the same (or near) sequence windows/truncations
• whether the “≥95% identity” and truncation rules overlap with known hyaluronidase isoforms used clinically or disclosed in recombinant form

Non-infringement arguments will most likely focus on:

• sequence identity calculation methodology
• differences in glycosylation occupancy or the asparagine attachment site
• pH/activity characterization that disputes “neutral active”

---

Key claim-critical elements for due diligence (what must be checked in any competitor or litigant product)

Use this as a checklist for infringement or FTO review of any hyaluronidase glycoprotein intended for these indications.

Protein identity

• Does the product protein correspond to AA 36-477 to 36-483 windows of SEQ ID NO:1 (or claim 20 truncation scheme including AA 36-464 with truncation at 477-483)?
• Is substitution permitted but still within:
  • ≥95% AA identity (claims 1/6/16)
  • or the tighter paths in claim 20 (>99% or >97% with truncation at 483)?

Glycosylation requirement

• Is there at least one sugar moiety covalently attached to an asparagine residue?
• Is the glycosylation retained after any polymer conjugation?

Enzymatic activity profile

• Is the glycoprotein “neutral active” under relevant conditions used by the assay method for enzyme activity?

Indication and mechanism

• For herniated disk:
  • is it treated by chemonucleolysis via contacting the hernia?
• For broader disease:
  • does the disease context match “excess substrate accumulation in diseased tissue” and is substrate reduction claimed as the treatment effect?

Manufacturing embodiment overlap

• For CHO or mammalian secreted production:
  • does the expression vector incorporate the claimed polynucleotide ranges (SEQ ID NO:6 106-1446 or SEQ ID NO:48), and does the product match the secreted glycoprotein sequence?

---

Key Takeaways

• US 8,431,124 is anchored on a neutral-active hyaluronidase glycoprotein with asparagine-linked covalent sugar moieties and sequence identity rules tied to SEQ ID NO:1 windows/truncations (AA 36-477 to 36-483; claim 20 C-terminal truncation paths).
• The independent claims cover:
  • substrate-excess disease treatment (method framework in claim 1 and claim 20)
  • herniated disk treatment including lumbar intradiscal pressure (claim 2) and chemonucleolysis (claim 19)
• Claim defensibility is strongest against “generic hyaluronidase” competitors, because the protein is not merely hyaluronidase. It is defined by glycosylation, neutral activity, and specific sequence windows/identity thresholds.
• Claim risk concentrates around assay-defined “neutral active” and identity calculations (alignment/truncation boundaries), plus the ability for competitors to engineer proteins that fall below thresholds or alter the glycosylation pattern.

FAQs

1. Does US 8,431,124 cover any hyaluronidase treatment for herniated disks?
   No. Coverage requires a neutral-active glycoprotein with asparagine-linked sugar moieties and protein sequences meeting the enumerated SEQ ID NO:1 windows/identity thresholds.

2. What protein sequence features drive infringement risk?
   The claim-critical features are the AA windows 36-477 to 36-483 of SEQ ID NO:1, permitted substitutions with ≥95% identity, and claim 20’s C-terminal truncation scheme (including truncation at residues 477-483 with backbone including at least AA 36-464).

3. Can a competitor avoid the patent by using a different truncation endpoint?
   Yes in principle. The claims are anchored to truncations at residues 477-483 (claim 20) and enumerated windows in claims 1/5. A different C-terminal architecture can be outside the identity/truncation rules.

4. Do PEGylated or dextran-conjugated hyaluronidase products automatically infringe?
   No. Conjugation is only claimed as a dependent variant. The base glycoprotein still must meet the neutral-active, asparagine-glycosylated, SEQ ID NO:1 identity constraints.

5. What evidence matters most in a dispute over these claims?
   For validity and infringement: (i) sequence identity calculation to the claimed SEQ ID NO:1 windows and truncations, (ii) glycosylation on asparagine confirmation, and (iii) enzyme activity characterization supporting “neutral active.”

---

References

[1] US Patent 8,431,124. Claims as provided in prompt.

Details for Patent 8,431,124

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Bausch & Lomb Incorporated	VITRASE	hyaluronidase	Injection	021640	May 05, 2004		2029-04-16
Bausch & Lomb Incorporated	VITRASE	hyaluronidase	Injection	021640	December 02, 2004		2029-04-16
Amphastar Pharmaceuticals, Inc.	AMPHADASE	hyaluronidase	Injection	021665	October 26, 2004		2029-04-16

International Patent Family for US Patent 8,431,124

Country	Patent Number	Estimated Expiration
South Africa	200707898
South Africa	200507978
World Intellectual Property Organization (WIPO)	2006091871