Patent: 5,827,721

Summary for Patent: 5,827,721

Title:	BH55 hyaluronidase
Abstract:	The invention features a purified hyaluronidase BH55 polypeptide isolated from a mammalian species, preferably bovine or human. The invention also features DNA encoding BH55, vectors and transformed host cells containing DNA encoding BH55, methods of making BH55 hyaluronidase polypeptides, and antibodies that specifically bind BH55.
Inventor(s):	Stern; Robert (San Francisco, CA), Frost; Gregory I. (San Francisco, CA), Hall; Jackson (San Francisco, CA), Shuster; Svetlana (San Francisco, CA), Colbern; Gail T. (Pacifica, CA), Formby; Bent (Santa Barbara, CA)
Assignee:	The Regents of the University of California (Oakland, CA)
Application Number:	08/919,089
Patent Claims:	see list of patent claims

United States Patent 5,827,721 (BH55 Hyaluronidase): Claim Analysis and US Patent Landscape

US Patent 5,827,721 claims a bovine hyaluronidase (“BH55”), anchored on an isolated DNA molecule encoding the enzyme, with dependent claims narrowing to specific sequence identity (SEQ ID NOs) and expressing embodiments (vectors, transformed cells, and production methods). The core claim set is straightforward: it protects nucleic acids, expression constructs, production in cultured cells, and the corresponding amino-acid sequence content that defines BH55. Below is a claim-by-claim technical and legal analysis and a critical view of the likely US patent landscape around hyaluronidase DNA and expression.

What do the independent claims actually cover?

Claim 1: “isolated DNA molecule encoding bovine BH55 hyaluronidase”

Claim 1 is the primary coverage. It defines:

• Subject matter: isolated nucleic acid.
• Function/definition: encodes bovine BH55 hyaluronidase.
• Scope limiter: “isolated DNA molecule” (not necessarily a specific length, structure, or promoter-free construct).

Critical coverage observation: Claim 1 can be broad in form (any isolated DNA that encodes BH55). It is narrow only in content: it must encode the BH55 enzyme. If “BH55” is defined in the specification by one or more amino-acid sequences and/or nucleic acid sequences, Claim 1’s breadth effectively tracks the accuracy and completeness of that definition.

Claim 2: “DNA molecule, or degenerate variants thereof, encoding BH55 hyaluronidase”

Claim 2 expands Claim 1 by adding:

• Degenerate variants: codon substitutions that preserve the amino-acid sequence.

Critical coverage observation: This is standard “degenerate codon” claiming, designed to capture alternative DNA sequences that still encode the same protein. Enforcement strength depends on how the patent defines BH55 at the amino-acid level (and how well the specification discloses the degenerate encoding).

Claim 3: operably linked to regulatory sequences, including a promoter

Claim 3 covers expression-ready nucleic acids:

• the BH55-encoding DNA is operably linked to regulatory sequences (at least a promoter).

Critical coverage observation: This claim targets the expression architecture. If the independent Claim 1 could be designed around by using expression cassettes with different regulatory logic, Claim 3 closes that gap because it does not require a particular promoter type. It requires only that a promoter be present as part of the regulatory sequences.

Claim 4: a vector comprising the DNA of Claim 1

This is a classic vector claim:

• a plasmid or viral vector containing the BH55-encoding DNA.

Critical coverage observation: Vector claims often overlap with transformed cell and method claims. As written, Claim 4 is not limited to a particular vector system (bacterial, yeast, mammalian, etc.) unless the specification restricts “vector” in context. That makes it a higher-value claim because it covers deliverables rather than just end-product proteins.

Claim 5: cultured transformed cell containing the DNA of Claim 1

This covers:

• transformed cells containing the BH55 DNA in culture.

Critical coverage observation: Depending on how “transformed” and “contains” are interpreted, this can reach a wide class of host systems. But it also makes Claim 5 dependent on whether the BH55 DNA is maintained as an integrated or episomal element in the host, which can matter in some infringement theories.

Claim 6: method producing BH55 hyaluronidase

Claim 6 claims: 1) culturing a cell transformed with a DNA molecule encoding BH55 hyaluronidase, 2) under conditions for expression, 3) isolating the produced BH55 hyaluronidase.

Critical coverage observation: This is the operational claim for manufacturing. It is typically enforceable even where the DNA is not transferred externally, because it covers the production process steps. It also aligns with standard biotech process claim formats.

How do the dependent sequence claims narrow the invention?

Claim 7: BH55 hyaluronidase comprises the amino acid sequence GPXPIYHIQEAVL (SEQ ID NO:1)

Claim 7 narrows to a specific peptide motif being present in the BH55 enzyme:

• GPXPIYHIQEAVL (X can vary depending on how the patent defines “X”; the claim as written uses “X” inside the sequence).

Critical coverage observation: This is a motif claim rather than a full-length protein claim. Motif claims can be attacked if the motif occurs in multiple proteins or variants. Conversely, the claim can still be valuable if the motif is unique within the BH55 family as disclosed.

Claim 8: BH55 comprises multiple amino-acid sequences (SEQ ID NOs:2-6) with Xaa wildcard

Claim 8 is a multi-epitope / multi-motif style limitation:

• SEQ ID NO:2: Val-Leu-Xaa-Arg-Glu-Pro-Ala-Gly-Ala-Val-Ile-Xaa-Gly-Tyr-Gly-Thr-Pro-Arg-Al a-Thr-Val-Thr-Val-Thr-Leu-Xaa-Arg
• SEQ ID NO:3: Gly-Pro-Ser-Ala-His-Ser-Val-Leu
• SEQ ID NO:4: Met-Lys-Lys-Gly-Thr-Arg-Val-Lys-Xaa-Asp-Ser-Asn
• SEQ ID NO:5: Lys-Pro-Gly-Gly-Pro
• SEQ ID NO:6: Xaa-Val-Phe-Gln-Val-Phe-Val-Ala-Xaa-Gly-Glu-Leu

with Xaa = any naturally occurring amino acid.

Critical coverage observation: The presence of multiple motifs reduces the risk that a coincidental short sequence matches BH55 by chance. The wildcard positions (Xaa) also broaden the covered space for natural variation at specific residues. This looks like the patent’s method to define BH55 when there are uncertain or variable positions across isolates, glycoprotein processing, or alignments across species or variants.

Claim strategy: What is the effective “coverage boundary” in practice?

The claim set follows a typical biotech pattern:

1) Broad nucleic-acid core (Claims 1-2) defined by encoding BH55. 2) Expression scaffolding (Claims 3-5) through promoter/regulatory linkage, vectors, and transformed cells. 3) Commercial production (Claim 6) through culture and isolation. 4) Protein/sequence tether (Claims 7-8) that anchors “BH55” to disclosed amino-acid features.

Critical consequence: If an accused product is a BH55 hyaluronidase protein variant that still contains the motif set in Claim 8, it is likely harder to design around purely at the sequence level. If it misses one motif, you can drive noninfringement arguments based on claim construction of “comprises” and the role of wildcards. If an accused entity uses an alternate DNA that encodes a BH55 protein, Claim 2 reduces the ability to avoid by codon re-encoding.

How strong are these claims for enforcement in the US?

Strength drivers

• Multiple claim formats: product (protein is not directly claimed as a standalone composition in your list), nucleic acid, vector, cell, and method. This provides multiple litigation entry points.
• Degenerate variants: reduces design-around at the DNA level.
• Motif-defined protein identity: gives claim scope a biological anchor that can be tested experimentally.

Vulnerability drivers

• “Isolated DNA” and “encoding BH55”: If the patent relies heavily on the definition of BH55 in the specification, claim scope may depend on how courts construe what is “BH55.” If BH55 is not sharply defined as a complete sequence, infringement and validity arguments can turn on whether motif-based definitions meet novelty/enablement standards.
• Motif claims with wildcards: Xaa wildcards can create overlap with other enzymes that share similar conserved regions. This can matter in both novelty and nonobviousness disputes, and in doctrine-of-equivalents analysis.

US patent landscape: where does 5,827,721 likely sit?

Landscape segment A: hyaluronidase gene cloning and recombinant expression

For hyaluronidase enzymes, US filings over many years typically cover:

• isolated nucleic acids encoding hyaluronidases (animal or microbial sources),
• vectors and expression constructs,
• recombinant production and purification,
• sometimes broad claims over hyaluronidase variants.

Where 5,827,721 fits: It is an enzyme-specific claim family anchored on bovine BH55 and its sequence motifs. That positioning matters: it is less likely to be blocked by generic “any hyaluronidase gene” prior art if the prior art does not disclose BH55 or the specific motif-defined BH55 identity.

Landscape segment B: cysteine/hyaluronidase-like enzymes and sequence-homology claiming

Many hyaluronidase patents rely on sequence identity ranges, degenerate variants, and motifs within enzyme catalytic domains. The BH55 claims resemble that style:

• “degenerate variants”
• motif-based amino-acid limitations

Implication: Even if another patent discloses recombinant bovine hyaluronidase genes, 5,827,721’s enforceability will hinge on whether the prior art discloses “BH55” as defined by the patent, not just “a hyaluronidase from bovine.”

Landscape segment C: vectors and transformed cell claims

Vector/cell claims in the US often face:

• overlapping earlier vector systems,
• obviousness based on standard cloning and expression techniques,
• and questions of novelty if the vector is conventional and only the insert is novel.

Implication: Claims 3-5 likely derive patentability from the specificity of the BH55 nucleic acid rather than from the vector itself.

Landscape segment D: manufacturing method claims

Process claims like Claim 6 are usually:

• easier to map to practice,
• but also vulnerable if the expression and purification steps are routine and the claimed novelty resides only in the BH55 DNA.

Implication: If a competitor practices recombinant expression of a BH55-like hyaluronidase, Claim 6 is often the most directly asserted pathway.

Critical view: likely claim construction and litigation friction points

1) What is “bovine BH55 hyaluronidase” as a legal entity?

Your provided claim text uses BH55 as a reference label, then provides peptide motifs (SEQ ID NOs) to define the enzyme. In infringement, a court will require that the accused protein “encodes” to an enzyme that satisfies the motif-based “comprises” limitations.

Key friction points:

• Whether motif presence is determined by linear sequence only or also by processed form and post-translational modifications (not explicitly in your claim list).
• Whether the wildcards (Xaa) expand the scope enough to cover near-homologs.

2) “Degenerate variants” and codon substitutions

If an accused construct encodes an amino-acid sequence that matches the BH55 motif set, Claim 2 will tend to capture codon substitutions. The practical boundary becomes whether the amino-acid sequence is still “BH55” under the motif definition.

3) Operably linked promoter requirement (Claim 3)

An accused expression system could argue that its regulatory architecture does not meet the claim limitation if promoters are absent or replaced by non-promoter control elements. Claim 3 requires a “promoter” as part of the regulatory sequences, so that is an explicit technical element.

4) Motifs as partial sequence constraints

Claims 7 and 8 do not require the full-length protein sequence in your list. If the specification defines BH55 by full-length sequence and the claims only require motifs, there may be broader scope than necessary, but that is generally favorable to the patentee. It also increases the chance of prior art proteins sharing the same motifs, which can create validity risk.

Business implications: where to attack or de-risk freedom-to-operate

If you are evaluating infringement risk

Focus on mapping these elements:

• Does the accused construct encode a protein that contains the motif set in Claim 8?
• Does the accused expression system use a promoter (Claim 3)?
• Are vectors or transformed cells involved (Claims 4-5)?
• Is the enzyme produced by culturing transformed cells and isolating the enzyme (Claim 6)?

A risk assessment should not treat BH55 as a vague label. It must be treated as a sequence-constrained entity through the motif set.

If you are designing around

The most realistic design-around levers in this claim set are:

• remove one or more motif features from the expressed enzyme sequence while preserving hyaluronidase function (hard biologically),
• avoid promoter-linked constructs if you can structure expression via promoter-like elements is difficult without falling into Claim 3,
• produce the enzyme via a non-transformed-cell pathway (difficult if the competitor uses recombinant expression).

Key Takeaways

• US 5,827,721 protects a bovine hyaluronidase “BH55” through an isolated DNA encoding BH55 (Claims 1-2), expression constructs (Claims 3-5), and a recombinant manufacturing process (Claim 6).
• The strongest identity anchor is Claim 8’s multi-motif amino-acid limitations with wildcard residues, supported by a single additional motif in Claim 7.
• Enforcement leverage comes from multiple claim categories (DNA, vector, transformed cell, method) and “degenerate variants” that reduce DNA-level design-around.
• Litigation friction likely centers on claim construction of “BH55” and whether an accused protein satisfies the motif-defined “comprises” limitations.

FAQs

1) Does US 5,827,721 claim the BH55 protein itself?

Your claim set as provided claims DNA molecules, vectors, transformed cells, and a method producing BH55 hyaluronidase. It does not present a standalone composition-of-protein claim in the text you supplied. Motifs define the BH55 hyaluronidase that the DNA encodes.

2) What is the practical difference between Claim 1 and Claim 2?

Claim 1 covers isolated DNA encoding BH55. Claim 2 extends that to “degenerate variants,” capturing codon-level sequence changes that preserve the same BH55 amino-acid identity.

3) Which claim most directly maps to a manufacturing operation?

Claim 6: culturing transformed cells under expression conditions and isolating BH55 hyaluronidase.

4) Are the motif-based claims broad or narrow?

They are narrower than “any bovine hyaluronidase,” but broader than full-length sequence claims because Claim 8 uses multiple motif constraints with Xaa wildcards rather than requiring a complete amino-acid sequence.

5) How does Claim 3 constrain expression system designs?

Claim 3 requires that the BH55-encoding DNA is operably linked to regulatory sequences including a promoter. Expression systems without a promoter element in the claimed arrangement can be a design-around path, though functionally “promoter-like” regulation may still be argued as a promoter.

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References

[1] US Patent No. 5,827,721. (n.d.). United States Patent and Trademark Office.

Details for Patent 5,827,721

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Bausch & Lomb Incorporated	VITRASE	hyaluronidase	Injection	021640	May 05, 2004		2017-08-27
Bausch & Lomb Incorporated	VITRASE	hyaluronidase	Injection	021640	December 02, 2004		2017-08-27
Amphastar Pharmaceuticals, Inc.	AMPHADASE	hyaluronidase	Injection	021665	October 26, 2004		2017-08-27
Akorn, Inc.	HYDASE	hyaluronidase	Injection	021716	October 25, 2005		2017-08-27