Patent: 5,075,222

Summary for Patent: 5,075,222

Title:	Interleukin-1 inhibitors
Abstract:	DNA sequences that encode Interleukin-1 inhibitors and recombinant-DNA methods for the production of interleukin-1 inhibitors are provided. The DNA sequences encode proteins having interleukin-1 inhibitors activity.
Inventor(s):	Hannum; Charles H. (Boulder, CO), Eisenburg; Stephen P. (Boulder, CO), Thompson; Robert C. (Boulder, CO), Arend; William P. (Denver, CO), Joslin; Fenneke G. (Denver, CO)
Assignee:	Synergen, Inc. (Boulder, CO)
Application Number:	07/506,522
Patent Claims:	see list of patent claims

United States Patent 5,075,222: IL-1 Inhibitor DNA and Expression Claims

United States Patent 5,075,222 claims an IL-1 inhibitor program built around isolated DNA sequences encoding interleukin-1 inhibitors (IL-1 inhibitors, including IL-1 inhibitors referred to as IL-1ra-like species) and the associated recombinant DNA constructs, host cells, and production methods. The claim set is layered: broad functional DNA definitions (including cross-hybridizing variants), nucleic-acid segment claims (positions 99 to 554 of “the sequence which follows”), and then standard recombinant DNA apparatus and method claims (vectors, host cells, culturing, and harvesting).

From a landscape perspective, the patent is best read as claiming a genus of IL-1 inhibitor–encoding sequences and their recombinant expression in bacteria and mammalian cells, with supporting examples of specific constructs and “GT10-lLli-2A.” The critical enforceability and commercial relevance hinge on (1) how far the cross-hybridization language sweeps, (2) whether the sequence “positions 99 to 554” are sufficiently specific to anchor a narrower disclosure-supported scope, and (3) whether later competitors map their products or platforms to non-infringing sequence space or alternative IL-1 inhibition modalities.

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What exactly does US 5,075,222 claim?

H2: What is the core independent claim scope? (Claim 1)

Claim 1 is an isolated DNA sequence encoding a physiologically functional IL-1 inhibitor (labeled IL-li). It is defined as selecting from two categories:

1. Direct encoding category: a DNA sequence that encodes IL-li X, IL-li alpha, or IL-li beta.
2. Functional cross-hybridization category:
   • a DNA sequence (i) that cross-hybridizes to a DNA sequence that encodes IL-li X, IL-li alpha, or IL-li beta, or
   • a DNA sequence (ii) that cross-hybridizes to a DNA sequence that is complementary to a DNA sequence that encodes IL-li X, IL-li alpha, or IL-li beta,
     where the DNA sequence of (i) or (ii) encodes a protein having IL-1 inhibitor activity.

This architecture is typical of early recombinant cytokine antagonist patents: it combines sequence identity/encoding with hybridization-based functional genus capture.

Operational consequence for infringement analysis: a competitor does not need to copy an exact claimed nucleotide sequence if it falls within the cross-hybridization boundary and encodes an IL-1 inhibitor protein.

H2: What is the tightest “named” construct claim? (Claim 2)

Claim 2 narrows to a specific recombinant DNA: “GT10-lLli-2A.” This is likely the example construct identifier referenced in the specification and prosecution history. It is the easiest place to tie scope to specific sequences and lab artifacts, but its protection depends on how directly a competitor’s materials match that construct.

H2: How does the patent narrow via sequence windows? (Claims 4–5)

Claims 4 and 5 claim isolated DNA sequences including nucleic acids from position 99 to 554 from “the sequence which follows” (shown as STR5 and STR6 in the claim text you provided).

Operational consequence: these claims can provide a more concrete infringement anchor if the “sequence which follows” is a specific disclosed sequence (or a known IL-1 inhibitor gene/isoform sequence) and if competitor sequences include the same region. Hybridization claims remain broad; region claims act as partial specificity.

H2: What does the patent cover beyond the DNA? (Claims 6–16)

The remainder tracks a standard recombinant DNA stack:

• Claim 6: recombinant DNA vector comprising the DNA sequence of claim 1.
• Claim 7–10: vector is an expression vector with regulatory elements; can be expressed in bacteria and mammalian cells.
• Claims 8–9: expression in bacteria and mammalian cells.
• Claims 11–16: cell host with the vector inserted, including microorganism (including E. coli) and mammalian cell (generic; later claim 26 specifies CHO).

The claim set is not limited to one expression system. It spans bacterial and mammalian expression, and it explicitly calls out Escherichia coli and CHO cells.

H2: What does it claim as a manufacturing method? (Claims 17–28, 29–31)

Claim 17 is a recombinant DNA method with steps: prepare encoding DNA (with the same selection/cross-hybridization definition), subclone into vector with regulatory elements, insert into a host capable of expression, culture under conditions, and harvest IL-1 inhibitor.

Claims 19–22 diversify the DNA origin: cDNA, genomic sequence, derived from mammalian cells, derived from human monocytes.

Claims 23–26 cover host categories: microorganism (E. coli), mammalian cells (CHO).

Claims 28–29 cover alternative formats:

• Claim 28: culturing a host with vector and harvesting protein.
• Claim 29: constructing an expression vector (preparing DNA and subcloning into an expression vector).

Claims 30–31 re-attach the IL-li X/alpha/beta encoding subset.

Operational consequence: infringement exposure also includes process steps (culture and harvesting), not only possession of DNA/vector materials.

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How broad is the patent in practice?

H2: Cross-hybridization language is the breadth driver

The functional capture in claim 1 is the most landscape-relevant element. It is broad because it includes nucleic acids that cross-hybridize to known IL-1 inhibitor genes and that encode an IL-1 inhibitor protein.

The key practical question in any FTO (freedom-to-operate) analysis is not what the competitor’s exact sequence is, but whether their sequence is within cross-hybridization parameters and encodes an IL-1 inhibitor protein.

H2: “Physiologically functional” adds a functional limitation, not a sequence boundary

“Physiologically functional” and “encodes a protein having IL-1 inhibitor activity” are functional constraints. They narrow away non-functional sequences, but they still permit a wide set of sequence variations as long as the translated protein has IL-1 inhibitor activity.

H2: Host range is wide

The patent covers bacterial and mammalian expression, including named host types. A competitor expressing the IL-1 inhibitor in a single proprietary system can still run into claims 7–12 if the product includes the claimed vector and encodes a claimed IL-1 inhibitor sequence.

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What is the most likely validity and enforceability pressure?

H2: Potential “genus with cross-hybridization” scrutiny

Early cytokine antagonists patents often faced challenge on whether the spec supports broad functional genus coverage and whether the claims are commensurate with the disclosure. While US practice depends on filing dates and the specific claim construction, the risk profile for such claim language typically comes from:

• Enablement and written description for the full breadth of hybridization-claimed sequences.
• Indefiniteness arguments around the operational meaning of “cross-hybridizes” without explicit conditions (temperature, stringency, probes).
• Obviousness if prior art already disclosed IL-1 inhibitor proteins and routine recombinant DNA expression.

In a landscape sense, this matters because challengers will target claim 1 first: it is where the broadest capture sits and where the most prior-art overlap is likely to occur.

H2: The “GT10-lLli-2A” claim is likely narrower but easier to map

If “GT10-lLli-2A” is a specific plasmid/construct described in the specification, invalidity may be harder to sustain for that exact configuration if competitors are copying an identified build. But this is typically less important commercially because product manufacturing rarely relies on a single historical plasmid identity.

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Where does the claim set overlap with common IL-1 inhibitor products?

H2: IL-1 inhibitor modality overlap

The patent is aimed at encoding and expressing IL-1 inhibitors, specifically labeled IL-li X, IL-li alpha, IL-li beta. This claim set is consistent with the family of IL-1 receptor antagonists and related inhibitors that bind IL-1 or block IL-1 signaling.

From a patent landscape standpoint, the most direct overlap tends to occur with:

• recombinant IL-1 antagonists produced by DNA expression,
• knock-on improvements in expression systems that still require the same core DNA/protein sequence space.

If a competitor’s therapeutic protein sequence falls into “IL-li alpha/beta/X” or encodes a functionally equivalent IL-1 inhibitor protein, then claim 1 hybridization language becomes the principal battleground.

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Patent landscape implications: how competitors design around

H2: Design-around options that typically matter for this claim structure

Given the claim structure, common defensive strategies are:

1. Sequence divergence beyond hybridization capture
   Competitors target changes that move nucleic acids outside hybridization boundaries and that reduce the chance of satisfying claim 1’s functional cross-hybridization capture.

2. Protein sequence divergence that still inhibits IL-1 by a different mechanism
   If a competitor uses a different IL-1 inhibition mechanism (different target, different inhibitor class), they reduce the chance their protein “encodes a protein having IL-1 inhibitor activity” as defined for the claimed IL-li species. Even when IL-1 inhibition is the therapeutic goal, patent infringement depends on whether the claimed sequences encode the same labeled IL-li inhibitors or cross-hybridizing DNA.

3. Expression platform changes that avoid claimed vectors
   Claims 6–12 are vector and host-specific, but they are still pegged to the claimed DNA sequence. Platform changes only help if the DNA itself is non-infringing.

4. Use of alternative DNA formats that avoid the particular sequence windows (claims 4–5)
   If claims 4–5 are anchored to positions 99–554 in a specific sequence disclosure, a competitor can focus on whether their DNA includes that region in the relevant form.

H2: Process claims increase exposure

Even if a competitor argues their DNA construct is outside claim 1, the manufacturing steps in claim 17 can create exposure if their vector/host and protein production steps are found to satisfy the claim elements.

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Claim-by-claim “what to test” checklist

H2: Infringement test priorities

1. Claim 1: map competitor IL-1 inhibitor protein sequence to IL-li X/alpha/beta and test whether their DNA cross-hybridizes to disclosed IL-li encoding sequences (and whether their DNA encodes IL-1 inhibitor activity).
2. Claims 4–5: compare competitor nucleic acid regions against the disclosed nucleic acid segment from positions 99 to 554.
3. Claims 6–10: confirm whether competitor vectors are expression vectors containing the claimed DNA sequence with regulatory elements enabling expression in bacteria/mammalian cells.
4. Claims 11–16: evaluate host systems (microorganism, E. coli, mammalian cells; especially CHO in claim 26).
5. Claims 17 and 28: examine the manufacturing process steps (subcloning, insertion, culturing, harvesting).

H2: Why claim 2 is a side-channel

Claim 2 (“GT10-lLli-2A”) is useful only if competitors use the same identified construct or if their constructs are direct equivalents that contain the same DNA sequence and functional elements. It is often less relevant unless a competitor’s plasmid can be matched closely to the example.

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Key Takeaways

• Claim 1 is the core asset: an isolated IL-1 inhibitor–encoding DNA sequence captured by both direct encoding of IL-li X/alpha/beta and a cross-hybridization + functional IL-1 inhibition framework.
• Claims 4–5 provide partial sequence anchoring by requiring nucleic acids from positions 99 to 554 of a disclosed sequence, which can materially affect infringement mapping if competitors’ DNA diverges in that region.
• The rest of the patent is standard recombinant stack: vectors, expression regulation elements, host cells (including E. coli and CHO), and production methods (culture and harvesting).
• Design-around leverage typically comes from moving outside cross-hybridization capture and/or using different IL-1 inhibitor modalities, not from switching expression hosts alone, because the vector and host claims are still tied back to claim 1’s DNA definition.
• Process claims broaden infringement risk by covering recombinant DNA method steps, which means manufacturing evidence can be outcome-determinative.

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FAQs

1. Which claim defines the broadest DNA scope?
   Claim 1, because it covers direct encoding of IL-li X/alpha/beta and sequences that cross-hybridize and encode an IL-1 inhibitor protein.

2. Do the vector and host claims depend on the DNA claim?
   Yes. Claims 6–12 and 11–16 are all tied to the DNA sequence of claim 1 and its expression in specified hosts.

3. What role do claims 4–5 play in enforcement?
   They potentially narrow infringement by requiring inclusion of nucleic acids from position 99 to 554 from the patent’s disclosed sequence.

4. Is the manufacturing step protection limited to one cell system?
   No. Claim 17 and related method claims cover microorganism systems and mammalian cell systems, including CHO.

5. What is the main design-around path against claim 1?
   Sequence and functional divergence: reduce the likelihood of satisfying the cross-hybridization and IL-1 inhibitor functional encoding requirements, or switch to a different IL-1 inhibition modality not captured by the claimed IL-li gene/protein definitions.

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References

[1] United States Patent 5,075,222 (claims as provided).

Details for Patent 5,075,222

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Swedish Orphan Biovitrum Ab (publ)	KINERET	anakinra	Injection	103950	November 14, 2001		2010-04-06

International Patent Family for US Patent 5,075,222

Country	Patent Number	Estimated Expiration
South Africa	911981
South Africa	905593
South Africa	894052
World Intellectual Property Organization (WIPO)	9534326
World Intellectual Property Organization (WIPO)	9216221
World Intellectual Property Organization (WIPO)	8911540
United States of America	6858409