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Patent landscape, scope, and claims: |
Executive summary
US Patent 11,072,586 claims solid-state crystalline polymorphs of eltrombopag choline (Forms A, B, and C) defined by XRPD peak positions (and optional additional peaks), plus composition, formulation, and medical-use claims that track those polymorphs. The claim scope is tightly anchored to crystal identity by diffraction fingerprint rather than general “polymorph-yield” language. Enforceability is therefore most sensitive to (1) whether an accused product contains the claimed polymorph (or a closely overlapping XRPD pattern that still falls within the ±0.2° window), and (2) whether it satisfies the claim’s “one or more of” XRPD criteria plus the optional additional-peak limits.
US Patent 11,072,586 scope: what crystalline forms of eltrombopag choline are actually claimed?
What is claimed in plain terms
Claims 1–7 are directed to solid-state crystalline forms of eltrombopag choline selected from:
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Form A (Claim 1(A); dependent Claims 2–3)
- Core XRPD peak set includes peaks at 11.3, 14.7, 15.4, 16.0, 24.1 degrees 2θ with ±0.2° tolerance.
- Claim 1 also permits an alternative definition using “XRPD pattern as depicted in FIG. 1.”
- Dependent Claim 3 adds: Form A is also characterized by the core set plus one to seven additional peaks chosen from 12.0, 12.7, 14.1, 20.3, 20.9, 24.8, 27.0 (each ±0.2°), depending on selection.
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Form B (Claim 1(B); dependent Claims 4–5)
- Core XRPD peak set includes peaks at 7.0, 10.2, 13.9, 14.9, 18.3, 21.6, 26.0 degrees 2θ with ±0.2° tolerance.
- Also defined by “XRPD pattern as depicted in FIG. 2.”
- Dependent Claim 5 adds: core set plus one to four additional peaks chosen from 7.4, 16.7, 19.9, 23.9 (±0.2°).
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Form C (Claim 1(C); dependent Claims 6–7)
- Core XRPD peak set includes peaks at 10.9, 14.2, 15.5, 21.9, 26.9 degrees 2θ with ±0.2° tolerance.
- Also defined by “XRPD pattern as depicted in FIG. 5.”
- Dependent Claim 7 adds: core set plus one to four additional peaks chosen from 11.3, 15.0, 21.2, 22.5, 25.6 (±0.2°).
Claim 1: how broad is it in practice?
Claim 1 uses “selected from” (A/B/C) and for each form it accepts:
- Either one or more of the listed XRPD numeric peak criteria and/or the figure-based pattern definition,
- with “combinations of any i–ii.”
This drafting generally makes Claim 1 more inclusive than a claim that would require the full numeric set and a full figure match simultaneously. If an accused material shows enough of the listed features under “one or more of the following” and/or matches the figure-defined pattern, it can fit.
How the ±0.2° tolerance affects infringement and design-around
Each listed peak position has a ±0.2° band. That window matters for:
- XRPD instrumental variability (sample prep, preferred orientation, background handling)
- peak shifting due to micronization, humidity, hydrate/solvate interconversions, and thermal history
- mixture effects (minor polymorph coexisting with claimed form)
For enforceability, the patent’s “fingerprint” approach can be attacked or supported based on whether the claimed peak positions land within those tolerances after normalization and smoothing.
Which XRPD peak sets define Form A, Form B, and Form C, and how do the dependent claims narrow them?
Key XRPD definitions by claim
| Claimed polymorph |
Claim(s) |
Core peaks (2θ, degrees) |
Tolerance |
| Form A |
1(A), 2 |
11.3, 14.7, 15.4, 16.0, 24.1 |
±0.2° |
| Form B |
1(B), 4 |
7.0, 10.2, 13.9, 14.9, 18.3, 21.6, 26.0 |
±0.2° |
| Form C |
1(C), 6 |
10.9, 14.2, 15.5, 21.9, 26.9 |
±0.2° |
Dependent narrowing: additional-peak constraints
Form A additional peaks (Claim 3)
- Allowed additional peaks (choose 1–7): 12.0, 12.7, 14.1, 20.3, 20.9, 24.8, 27.0 (±0.2°)
Form B additional peaks (Claim 5)
- Allowed additional peaks (choose 1–4): 7.4, 16.7, 19.9, 23.9 (±0.2°)
Form C additional peaks (Claim 7)
- Allowed additional peaks (choose 1–4): 11.3, 15.0, 21.2, 22.5, 25.6 (±0.2°)
Implication: dependent claims are not “stricter” by excluding other peaks; they are “stricter” by specifying that the pattern includes the core plus at least a minimal number of additional peaks selected from a defined set. That creates two practical litigation questions:
- does the accused pattern contain the core peaks within tolerance; and
- does it include at least the required number of “additional” peaks from the allowed list.
What composition, formulation, and method-of-use claims are tied to the crystalline forms?
Composition and formulation claims
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Claim 8: “A pharmaceutical composition comprising the crystalline form according to claim 1.”
Scope: product that includes Form A/B/C material as claimed crystalline form; does not require an explicit excipient list (that is Claim 10).
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Claim 10: “A pharmaceutical formulation comprising the crystalline form according to claim 1, and at least one pharmaceutically acceptable excipient.”
Scope: formulation with excipients; still anchored to the crystalline form.
Medical use and treatment claims
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Claim 9: “Use of the crystalline form according to claim 1 in the preparation of pharmaceutical compositions and/or formulations.”
This is a classic “manufacturing/use” tether claim.
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Claim 11: “The crystalline form according to claim 1, for use as a medicament.”
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Claim 12: “The crystalline form according to claim 1, for use in the treatment of Idiopathic thrombocytopenic purpura, Thrombocytopenia and Aplastic anemia.”
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Claim 13: “A method of treating Idiopathic thrombocytopenic purpura, Thrombocytopenia and Aplastic anemia comprising administering a therapeutically effective amount…” of the claimed crystalline form.
Litigation-relevant claim structure
The dataset creates a typical infringement map:
- Polymorph identity is the gating issue for Claims 1–7.
- If polymorph identity is established, then Claims 8–13 generally fall if the accused product also performs the “composition/formulation/use/treatment” functions.
For challenging validity, the strongest pressure points typically target the novelty and non-obviousness of the claimed polymorph(s) and the sufficiency/clarity of XRPD-based identification.
How strong is the patent estate likely to be based on the claim architecture of US 11,072,586?
Strength drivers
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Definite crystallinity definition
The claims identify polymorphs by explicit XRPD peaks and figure references. That supports “objective boundaries” for claim scope.
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Tight numerical peak sets
Core peak lists have 5 peaks (Form A), 7 peaks (Form B), and 5 peaks (Form C). That increases the probability that a truly different polymorph will not accidentally satisfy all required (or “one or more,” depending on interpretation) core features.
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±0.2° tolerance
The fixed window is a concrete claim term that can be tested and litigated.
Vulnerability drivers
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“One or more of the following” plus figure options
Claim 1’s use of “data selected from one or more of the following” can broaden scope. If the numeric criteria require only partial compliance, an accused pattern may argue it does not meet the intended full fingerprint. Conversely, the patentee will argue that enough features fall within the claim language.
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Optional additional peaks are permissive, not exclusive
Dependent Claims 3/5/7 require inclusion of core plus at least one to several additional peaks chosen from a list, but do not clearly state limits on other peaks outside the list. This can complicate infringement analytics because real-world XRPD patterns can have many peaks.
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Mixtures and processing effects
If an accused product contains a mixture, the infringement question becomes whether the accused polymorph is present at an interpretable level and whether the measured pattern still satisfies the claim-defined peaks within tolerance.
What generic entry risks exist if a filer attempts to launch eltrombopag choline using a different crystal form?
Risk profile based on claim tethering
Any generic or authorized alternative that uses eltrombopag choline as API must ensure that the API’s solid form does not infringe Claims 1–7.
- If the generic uses a different polymorph not matching the Form A/B/C XRPD fingerprint, it can try to avoid Claims 1–7.
- If it uses a mixture including the claimed form, the measured XRPD may still capture the core peaks, and Claim coverage can attach.
Practical design-around constraints
Given the narrow peak lists, a design-around typically needs a polymorph that shifts key peaks outside the ±0.2° bands. Milling, recrystallization solvents, drying conditions, and storage RH can all drift form populations and peak positions, so a “paper” form change can fail under product-specific testing.
How do these claims map to Paragraph IV, ANDA, or 505(b)(2) litigation theories?
Likely infringement theories
- Plaintiffs will test accused API and drug product XRPD against the claim-defined peak sets.
- Plaintiffs will argue that the accused form is Form A/B/C if peaks fall within tolerance and optional additional peak requirements are met.
Likely defense theories
- “Different polymorph” argument using XRPD patterns that miss at least one core peak within tolerance.
- “Non-infringement of dependence” arguments: if Form A requires core plus additional peaks under dependent claims, and the pattern lacks enough qualifying additional peaks from the allowed list.
- Claim construction battles over “data selected from one or more of” and the meaning of “XRPD pattern as depicted in FIG. 1/2/5.”
Because XRPD interpretation is a technical and evidentiary issue, the case outcome often depends on expert alignment on instrument settings, preprocessing, and peak picking.
Which jurisdictions’ regulatory status matters, given the US patent claims are solid-state polymorph claims?
This specific prompt contains only the US patent number and claim text, without the Orange Book listing, FDA drug approval, or the patent’s listed expiration. With only the claim scope provided, the key US regulatory implication is:
- If US eltrombopag products list this patent in Orange Book as covering a specific drug product and strength/dosage form, ANDA filers face risk of a patent challenge and potential 30-month stay depending on the filing type and challenge timing.
- If not listed, the scope still matters for general enforcement but not necessarily for Orange Book-driven 505(j) timelines.
No Orange Book status details can be asserted from the supplied information.
What does the claim language imply about manufacturing controls for eltrombopag choline crystallization?
Manufacturing sensitivity implied by the claims
Because identity is determined by XRPD peaks, manufacturing controls that affect:
- nucleation and crystallization temperature-time profile
- solvent system and antisolvent choice
- drying endpoint and residual solvent/solvate risk
- humidity exposure and solid-state stability
- milling and particle size changes that can shift peak intensities and apparent positions
are directly relevant to whether the produced API matches Form A/B/C.
Key Takeaways
- US 11,072,586 claims eltrombopag choline crystalline Forms A, B, and C defined primarily by XRPD peak positions with ±0.2° tolerance, plus optional additional peaks in dependent claims.
- Claim 1 is the broad anchor; Claims 2/4/6 define core peak sets for each form, while Claims 3/5/7 add mandatory minimum inclusion of additional peaks from defined lists.
- Claims 8–10 cover compositions and formulations containing the claimed crystalline form(s).
- Claims 11–13 cover medicament use and treatment of ITP, thrombocytopenia, and aplastic anemia, tethered to the crystalline forms.
- In litigation or design-around strategy, the primary battleground is whether the accused API or product exhibits the claimed XRPD fingerprint within the tolerances and meets any dependent additional-peak requirements.
FAQs
1) Can a mixture of polymorphs infringe a crystalline form claim defined by XRPD peak positions?
Yes, if the measured XRPD contains the claimed core peaks within ±0.2° (and satisfies the dependent additional-peak constraints where applicable), claim language permits matching to the claimed crystalline form.
2) Does the presence of extra XRPD peaks outside the listed additional-peak sets automatically avoid infringement?
Not on its own, because the dependent claims specify inclusion of required peaks but do not clearly disclaim other peaks.
3) How do the “XRPD pattern as depicted in FIG. 1/2/5” terms affect scope?
They add an alternative identification path that can reduce reliance on exact numeric lists, raising claim construction and expert-evidence issues.
4) What is the most direct way to assess infringement risk for a generic eltrombopag choline product?
Compare XRPD peak positions (with consistent instrument settings) for the accused API and/or final product against the core peak lists and dependent additional-peak thresholds.
5) Are medical-use claims likely to be easier to enforce than the polymorph claims?
They typically depend on proving the claimed crystalline form is present, since the treatment/manufacturing/use claims are tethered to the crystalline forms defined in Claims 1–7.
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