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Patent landscape, scope, and claims: |
United States Patent 6,372,780 (US6372780): What Is Claimed and How It Sits in the Drug-Patent Landscape
US 6,372,780 is a US method-of-treatment patent that claims using a defined chemical scaffold (Formula (I) with a highly variable substituent system) to treat “abnormal cell proliferation” in a mammal, explicitly where the target cell line expresses multidrug resistance P-glycoprotein (mdr1). The claims then narrow by specifying tumor type (colon cancer), administration routes, and combinations with other antineoplastic modalities. The enforcement value sits in the breadth of Formula (I) plus the functional tether to mdr1-positive disease biology.
Claim backbone: what the patent actually covers
The independent claim (Claim 1) is a method claim with the following gating elements:
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Indication / disease biology
- “abnormal cell proliferation”
- the relevant “cell line” is one “expressing a multidrug resistance P-glycoprotein (mdr1)”.
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Therapeutic act
- “administering … an effective amount” of a compound of Formula (I) (or a “pharmaceutically acceptable salt or solvate”).
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Chemical scope
- Formula (I) is expressed through variables Z, R1, R2, R3, R4, R5 with broad substitution definitions.
- The patent’s substituent language covers many families of substituents:
- R1 includes benzoyl, thenoyl, furoyl, and acyl-like groups and a broad R2–O–CO– motif.
- R3 includes diverse alkyl/alkenyl/alkynyl, cycloalkyl, phenyl/naphthyl, and aromatic heterocycles with substitution rules.
- R4 and R5 include alkoxy/alkenyloxy/alkynyloxy/cycloalkoxy variants, thioethers, carbamoyl and cyano-containing options, plus heterocycle-linked N-substituents.
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Dependent claim narrowing
- Several dependent claims narrow Z/side-group definitions and provide a specific exemplar compound.
How broad is the chemical language in Claim 1?
Claim 1 uses a classic “Markush” style approach: large combinatorial sets of substituents connected to Formula (I). The practical breadth is in two places:
- Z variable: “hydrogen” or a radical of Formula (II).
- R-group combinatorics: multiple substituent positions each allow wide classes (alkyl 1 to 8 carbons in some positions; aryl and heteroaryl options; halogen, alkoxy, cyano, carboxyl; and several heterocyclic variants).
Even without reconstructing the full structure from the text, the claim language is structured to capture:
- broad acyl or acyloxy-related groups at R1 (and at the R2–O–CO– component),
- broad hydrocarbon/aromatic/heteroaromatic substitution at R3,
- broadly substituted ether or related linkers at R4 and R5.
What is the single explicit compound called out?
Claim 5 identifies a specific compound of Formula (I) as an exemplar within the claimed scope:
- 4α-acetoxy-2α-benzoyloxy-5β,20-epoxy-1β-hydroxy-7β,10β-dimethoxy-9-oxo-11-taxen-13α-yl
- (2R,3S)-3-tert-butoxycarbonylamino-2-hydroxy-3-phenyl-propionate
- plus salts/solvates.
This matters because it acts like an anchor for claim construction and claim charting: enforcement can target that exemplar compound even if proving the full Markush permutations is harder than proving embodiment-specific infringement.
What do dependent claims add (coverage expansion vs narrowing)?
Z narrowing and substituent tightening
Claims 2 to 4 progressively narrow what Z, R1, R2–O–CO–, R3, R4, and R5 can be.
Net effect: dependent claims provide narrower slices that can support enforcement even if accused products map more cleanly to a subset.
Taxen-based exemplar and administration route
- Claim 10 again ties back to the exemplar compound from Claim 5 under narrowed substituent conditions.
- Claims 11–14 address parenteral and specific injection routes:
- Claim 11: “administered parenterally.”
- Claim 12: “intravenously, intraperitoneally, intramuscularly, or subcutaneously.”
- Claim 14: ties route language into a narrower exemplar (notably with a typographical inconsistency in the text you provided: “R4 and R6” and “2(2R,3S)” appear where the numbering suggests “R4 and R5” and a consistent stereochemical listing; claim construction in court would follow the printed patent text).
The coverage value of these dependent claims is practical: they can preserve enforceability when an accused program uses a different delivery route than an independent claim would otherwise require.
Disease and combination-therapy scope
Colon cancer as a target indication
- Claim 6 specifies: “abnormal cell proliferation is colon cancer.”
This is important because it creates a narrower method claim that can cover a targeted clinical use even if mdr1-positive expression is established only in colon cancer cell lines.
Combination therapy with standard oncology modalities
- Claim 7: method “performed concurrently with at least one additional therapeutic treatment.”
- Claim 8: additional therapy includes:
- “at least one antineoplastic drug”
- “monoclonal antibody”
- “immunotherapy”
- “radiotherapy”
- “biological response modifier”
Thus, the patent supports combination-therapy labeling-style infringement arguments: a regimen that includes the claimed Formula (I) compound plus any of these modalities “concurrently” can fit dependent claims.
Patent landscape implications for US6372780
1) This is a method-of-treatment patent with a defined chemical core
US6372780 is not a “composition of matter” claim in the text shown; it is a method claim tied to administering a compound of Formula (I) for mdr1-expressing abnormal proliferation. That shapes the landscape:
- The patent tends to be highly relevant for combination regimens and clinical protocols rather than for bulk chemical manufacturing.
- It can still be important if the relevant competing products are identical or closely equivalent in active ingredient structure and dosing, because method claims can be asserted regardless of how the composition is manufactured.
2) The mdr1 tether drives a narrower biological hypothesis
Most oncology method claims are generic (“treat cancer”). Here, the claim explicitly requires that the cell line expresses P-glycoprotein (mdr1). That can do two things:
- It limits the claim to patients or contexts where mdr1 expression in the relevant cell line is present.
- It increases the evidentiary burden on the patentee to tie the claimed biology to the treated disease context, but it can also make the claim more defensible by distinguishing from generic cytotoxicity patents.
Business implication: for competitors, the existence of this patent creates friction in trials that target MDR1-positive settings unless they can design around the Formula (I) compound or change the claimed biological context.
3) The Markush breadth of Formula (I) creates a “design-around pressure”
Even though a single exemplar is stated, the claim is written to cover broad variation across substituent sets. Competitors attempting to design around face two layers:
- avoid the Formula (I) chemical space (substituent permutations),
- and avoid the method framing (mdr1-expressing cell lines with “effective amount” administration).
4) Route and concurrence dependent claims strengthen enforcement optionality
Route-specific dependent claims matter if an accused program argues non-infringement by route (e.g., oral vs parenteral). Here the claim covers multiple parenteral routes:
- intravenous, intraperitoneal, intramuscular, subcutaneous.
And combination-therapy depends on “concurrently” using a wide definition of oncology adjuncts. That makes the patent less vulnerable to “we used standard-of-care but not in the same way” arguments, as long as concurrency is met.
Practical claim-scope map (what to check in an accused product)
Infringement checklist against Claim 1
- Is the active pharmaceutical ingredient (API) within Formula (I)?
- Map substitutions at Z, R1, R3, R4, R5 to the claimed definitions.
- Is it administered to treat abnormal cell proliferation in a context where the treated cell line expresses mdr1 (P-glycoprotein)?
- Is dosing framed as an “effective amount” for that purpose?
- If not a straight shot, do dependent claims cover the exact use:
- colon cancer (Claim 6),
- parenteral route (Claims 11–13),
- concurrency with oncology modalities (Claims 7–8).
Infringement checklist against dependent claim emphasis
- If a product is used in colon cancer, Claim 6 becomes a direct anchor.
- If the product is dosed by IV or other parenteral route, Claims 11–13 tighten coverage.
- If used in combinations with monoclonals, immunotherapy, radiotherapy, or traditional antineoplastic drugs, Claims 7–8 strengthen regimen-based infringement.
Key Takeaways
- US 6,372,780 is a method-of-treatment patent centered on administering Formula (I) compounds to treat mdr1 (P-glycoprotein)-expressing abnormal cell proliferation.
- The claim language is broad on chemistry via Markush-defined substituent classes at Z, R1, R3, R4, R5, with a specific taxen-based exemplar explicitly named.
- Dependent claims add colon cancer, parenteral routes, and concurrent combination therapy across multiple oncology modality classes.
- The enforcement focus is clinical regimens (including combination protocols) in mdr1-positive contexts, not manufacturing of a composition.
FAQs
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Is US 6,372,780 a composition-of-matter patent or a method patent?
It is a method-of-treatment patent in the provided claim set, directed to administering a Formula (I) compound for treating abnormal proliferation with mdr1-expressing cell lines.
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What biological marker does the independent claim require?
The cell line must express multidrug resistance P-glycoprotein (mdr1).
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What cancer indication is explicitly included in dependent claims?
Colon cancer is explicitly recited (Claim 6).
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Does the patent cover combination therapy?
Yes. Dependent claims require the method be performed concurrently with additional therapeutic treatments such as antineoplastic drugs, monoclonal antibodies, immunotherapy, radiotherapy, or biological response modifiers.
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Which administration routes are covered?
The patent includes parenteral administration and specifies routes: intravenous, intraperitoneal, intramuscular, and subcutaneous.
References
- US 6,372,780. (n.d.). United States Patent: Method for treating abnormal cell proliferation using mdr1-expressing cell lines and compounds of Formula (I).
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