US Patent 9,255,087: Ensartinib ALK Cancer-Use Claims, Scope, Expiry and Patent Landscape
US Patent No. 9,255,087 protects therapeutic use of ensartinib, also known as X-396, against specified cancers and anaplastic lymphoma kinase, or ALK, activity. The patent is directed to methods of treatment, not the basic chemical composition of ensartinib. Its commercial relevance increased after FDA approval of Ensacove, the ensartinib product, for previously untreated ALK-positive locally advanced or metastatic non-small cell lung cancer in December 2024.[1]
The patent’s strongest practical coverage is claim 4, which covers treating non-small cell lung cancer with ensartinib, and claim 8, which requires ALK-positive tumors. Claims 11 and 12 separately target ALK-positive non-small cell lung cancer and colorectal cancer. The patent does not cover every use of ensartinib, every ALK inhibitor, or the manufacture of ensartinib.
What drug and mechanism does US Patent 9,255,087 cover?
The claimed active ingredient is:
N-[5-(3,5-difluorobenzyl)-1H-indazol-3-yl]-4-(4-methyl-piperazin-1-yl)-2-(tetrahydro-pyran-4-ylamino)-benzamide.
This compound is ensartinib, formerly designated X-396. Ensartinib is an orally administered small-molecule tyrosine kinase inhibitor that targets ALK. Its clinical development focused on ALK-positive non-small cell lung cancer, including disease involving central nervous system metastases.
The patent covers:
| Attribute |
Scope |
| Active ingredient |
Ensartinib or a pharmaceutically acceptable salt |
| Therapeutic target |
ALK |
| Patent type |
Method-of-treatment and target-inhibition patent |
| Key disease |
ALK-positive non-small cell lung cancer |
| Other listed diseases |
Colorectal cancer, neuroblastoma, glioblastoma and other cancers |
| Dosage form |
Not limited to a specific tablet, capsule or formulation |
| Route of administration |
Not expressly limited in the quoted claims |
| Patient selection |
General cancer population in claim 1; ALK-positive tumors in claim 8 |
| Manufacturing coverage |
None in the quoted claims |
| Composition-of-matter coverage |
None in the quoted claims |
What are the independent claims in US Patent 9,255,087?
The patent has three substantive independent claims.
Claim 1: Broad disease-list treatment claim
Claim 1 covers administering ensartinib, or a pharmaceutically acceptable salt, in an amount effective to treat a patient with one of the listed diseases.
The disease list includes:
- Breast cancer
- Lung cancer
- Non-small cell lung cancer
- Colorectal cancer
- Prostate cancer
- Ovarian cancer
- Endometrial cancer
- Gastric cancer
- Clear cell renal cell carcinoma
- Uveal melanoma
- Multiple myeloma
- Rhabdomyosarcoma
- Ewing’s sarcoma
- Kaposi’s sarcoma
- Medulloblastoma
- Anaplastic large cell lymphoma
- Neuroblastoma
- Glioblastoma
- Inflammatory myofibroblastic tumor
- Melanoma
- Retinoblastoma
- Squamous cell carcinoma
- Seminoma
- Teratocarcinoma
- Xeroderma pigmentosum
- Thyroid follicular cancer
The list contains repeated disease categories, including rhabdomyosarcoma and Ewing’s sarcoma. Those repetitions do not materially expand the legal scope.
Claim 1 is broad in disease coverage but narrower than a composition claim because an accused product must be administered for treatment of a listed disease. It also requires the claimed chemical entity or a pharmaceutically acceptable salt.
Claim 8: ALK-positive cancer claim
Claim 8 covers treating a patient with cancer when the patient’s tumors are ALK-positive. This claim is more closely aligned with the approved clinical use of ensartinib than claim 1.
The claim requires:
- A patient with cancer;
- Tumors that are ALK-positive; and
- Administration of an effective amount of ensartinib or a pharmaceutically acceptable salt.
Claim 8 does not require non-small cell lung cancer. The dependent claims narrow the cancer type.
Claim 15: ALK activity inhibition
Claim 15 covers contacting ALK with an effective amount of ensartinib or a pharmaceutically acceptable salt.
This is a target-inhibition claim rather than a patient-treatment claim. It may reach research, screening or ex vivo applications if the required contact with ALK and effective inhibitory amount are present. It does not expressly require a cancer patient or a particular tumor type.
How do the dependent claims narrow the patent scope?
Claims 2 through 7 narrow claim 1 by selecting subsets of diseases. Claims 9 through 14 narrow claim 8 by selecting cancer types.
| Claim |
Limitation |
Commercial relevance |
| 1 |
Ensartinib treatment for any listed disease |
Broadest disease-use claim |
| 2 |
Breast cancer, NSCLC, colorectal cancer, prostate cancer, melanoma, neuroblastoma or glioblastoma |
Intermediate disease grouping |
| 3 |
NSCLC, colorectal cancer, neuroblastoma or glioblastoma |
Focused cancer grouping |
| 4 |
NSCLC |
Core approved-product relevance |
| 5 |
Colorectal cancer |
Separate disease-use protection |
| 6 |
Neuroblastoma |
Pediatric and oncology research relevance |
| 7 |
Glioblastoma |
Central nervous system oncology relevance |
| 8 |
Treatment of ALK-positive cancer |
Biomarker-defined treatment claim |
| 9 |
ALK-positive breast cancer, NSCLC, colorectal cancer, prostate cancer, melanoma, neuroblastoma or glioblastoma |
Biomarker plus disease subset |
| 10 |
ALK-positive NSCLC, colorectal cancer, neuroblastoma or glioblastoma |
Narrower biomarker subset |
| 11 |
ALK-positive NSCLC |
Strongest alignment with FDA-approved use |
| 12 |
ALK-positive colorectal cancer |
Separate biomarker-defined use |
| 13 |
ALK-positive neuroblastoma |
Narrow pediatric oncology use |
| 14 |
ALK-positive glioblastoma |
Narrow CNS oncology use |
| 15 |
Inhibition of ALK activity |
Non-patient target-inhibition claim |
What cancers are most strongly protected by US Patent 9,255,087?
ALK-positive non-small cell lung cancer has the strongest commercial and regulatory connection to the patent.
Claim 4 covers NSCLC without expressly requiring ALK positivity. Claim 11 covers ALK-positive NSCLC. Claim 8 independently covers ALK-positive cancer, and claim 15 covers ALK inhibition.
This creates overlapping protection around the approved product:
- Claim 4: ensartinib for NSCLC;
- Claim 8: ensartinib for ALK-positive cancer;
- Claim 11: ensartinib for ALK-positive NSCLC;
- Claim 15: inhibition of ALK with ensartinib.
A generic manufacturer seeking approval for the same indication would face the greatest exposure under claims 4, 8 and 11. A product labeled only for a non-ALK cancer could still implicate claim 1 or another disease-specific claim, depending on the proposed label and actual use.
What is the patent expiration date for US 9,255,087?
The patent belongs to a 2011 priority lineage. Its nominal 20-year patent-term endpoint is in 2031, calculated from the earliest relevant nonprovisional filing date. The operative expiration date can be affected by patent-term adjustment and any applicable patent-term extension.
| Patent |
Subject matter |
Nominal term profile |
| US 9,255,087 |
Ensartinib treatment and ALK inhibition |
Approximately 2031, subject to PTA/PTE |
| Earlier composition patents |
Ensartinib chemical entity and related compounds |
Generally earlier than or around the method-of-use estate |
| Later formulation or clinical-use patents |
Product presentation, dosing or selected patient populations |
May extend protection beyond the core compound term |
Patent expiration should be evaluated against the complete family, not US 9,255,087 alone. A generic launch may remain blocked by a separate composition, formulation, dosing or method-of-use patent even after the ’087 patent expires.
What is the Orange Book status of ensartinib?
FDA approved Ensacove, containing ensartinib, for adults with locally advanced or metastatic ALK-positive NSCLC whose tumors have not previously been treated with an ALK inhibitor.[1]
The FDA Orange Book is the relevant source for listed patents and regulatory exclusivity. A patent is not enforceable against every possible generic use merely because it appears in the Orange Book. The listed patent must claim the approved drug, an approved method of use, or another subject matter permitted under the Hatch-Waxman listing rules.[2]
For ensartinib, the key Orange Book questions are:
- Whether US 9,255,087 is listed against the approved product;
- Whether additional ensartinib patents are listed;
- Whether the listing identifies the approved NSCLC indication;
- Whether FDA has assigned any pediatric exclusivity or other regulatory exclusivity;
- Whether a future ANDA applicant files a Paragraph IV certification.
The FDA’s approval of a new molecular entity ordinarily provides five years of NCE exclusivity, subject to statutory exceptions for certain patent certifications. Ensacove’s regulatory exclusivity and its patent protection operate independently. The NCE exclusivity period does not replace patent enforcement and does not necessarily end on the same date as the patent term.[1][3]
When does ensartinib lose exclusivity?
Ensartinib faces several separate exclusivity dates.
Patent exclusivity
The core US method-of-use patent has a nominal endpoint in approximately 2031, subject to patent-term adjustment or extension. Other patents may expire earlier or later.
FDA NCE exclusivity
Ensartinib received FDA approval as a new active ingredient. The statutory NCE exclusivity period generally runs for five years from approval, with limited restrictions on ANDA filing during the first four years when no qualifying Paragraph IV pathway applies.[3]
Orphan-drug exclusivity
The approved indication is ALK-positive NSCLC, not a disease category that is ordinarily treated as a single rare-disease orphan indication. Orphan exclusivity should not be assumed without an FDA orphan designation and approval listing.
Pediatric exclusivity
A six-month pediatric extension requires completion of an FDA Written Request and satisfaction of the statutory requirements. It cannot be inferred from the approval alone.
Are there Paragraph IV challenges to US 9,255,087?
A Paragraph IV challenge would assert that a listed patent is invalid, unenforceable or not infringed. It could be filed by an ANDA applicant seeking approval to market a generic ensartinib product before patent expiration.
Potential challenge theories include:
- Lack of enablement for the full disease list;
- Written-description issues involving the breadth of the cancer indications;
- Obviousness based on earlier ALK inhibitors and the claimed chemical structure;
- Lack of adequate clinical or mechanistic support for non-NSCLC uses;
- Noninfringement based on a narrower generic label;
- Invalidity of the ALK-positive patient-selection limitations;
- Failure of the patent to claim the approved method in a properly listable manner.
The FDA Orange Book and federal district court docket records are the controlling sources for identifying an actual Paragraph IV filing or Hatch-Waxman suit. A Paragraph IV certification is not itself proof that the patent is invalid. It is a statutory notice and litigation trigger.
Which companies are challenging ensartinib patents?
The commercial field includes Xcovery, a subsidiary of Betta Pharmaceuticals, as the original developer and commercial sponsor of Ensacove. Innovent Biologics has been associated with commercialization and development arrangements for ensartinib in China and selected markets.[4]
No biosimilar company is relevant because ensartinib is a chemically synthesized small molecule. Generic-drug companies, rather than biosimilar manufacturers, would be the likely challengers under an ANDA pathway.
A public challenge assessment should distinguish:
- An ANDA filing;
- A Paragraph IV notice letter;
- A filed Hatch-Waxman action;
- A declaratory-judgment action;
- An inter partes review petition;
- A post-grant review;
- A commercial licensing or regional development dispute.
These events have different legal effects. The absence of a reported challenge is not equivalent to a judicial determination that the patent is valid.
How strong is the patent estate for ensartinib?
The ’087 patent is commercially meaningful but has a narrower legal position than a composition-of-matter patent.
Strengths
- It names ensartinib specifically.
- It covers the approved disease area through claims 4 and 11.
- It includes both general treatment and ALK-positive patient-selection claims.
- It includes a direct ALK-inhibition claim.
- The claims cover pharmaceutically acceptable salts.
- Multiple dependent claims create alternative infringement positions.
Weaknesses
- The patent does not cover the basic chemical composition in the quoted claims.
- It does not claim a specific dose, schedule or formulation.
- It includes a broad cancer list that may create enablement and written-description pressure.
- Non-NSCLC disease claims may have limited commercial value without approved indications.
- A generic could seek a carved-out label for unprotected uses, subject to actual use and inducement risks.
The strongest enforcement case would involve a generic product labeled for ALK-positive NSCLC. The weakest practical cases would involve unapproved cancers for which there is no established ensartinib market and limited clinical evidence.
What formulations and manufacturing processes are protected?
US 9,255,087, based on the quoted claims, does not require:
- A tablet;
- A capsule;
- A particular excipient;
- A specified particle size;
- A solid dispersion;
- A controlled-release system;
- A particular salt-selection process;
- A manufacturing route;
- A crystallographic form;
- A purity threshold; or
- A specific dosage strength.
A formulation or process patent would need to be analyzed separately. Such patents could create additional barriers even if a generic avoids the ’087 method claims.
For a generic manufacturer, the main technical barriers are likely to include chemical synthesis, control of regioisomers and impurities, salt or polymorph selection, analytical reference standards and bioequivalence. Those issues can delay entry but do not independently extend the legal term of US 9,255,087.
How does US 9,255,087 compare with competing ALK inhibitor patents?
| Drug |
Primary developer |
Main target profile |
Typical patent risk |
| Ensartinib |
Xcovery/Betta Pharmaceuticals |
ALK, with CNS-focused development |
Method-of-use, composition and possible formulation patents |
| Crizotinib |
Pfizer |
ALK, ROS1, MET |
Mature composition and method-of-use estate |
| Alectinib |
Roche/Chugai |
ALK |
Composition, formulation and dosing patents |
| Brigatinib |
Takeda |
ALK and related kinases |
Composition, method-of-use and dosing protection |
| Lorlatinib |
Pfizer |
ALK and ROS1 |
Macrocyclic composition and method-of-use protection |
| Ceritinib |
Novartis |
ALK |
Composition and formulation protection |
Ensartinib competes most directly with alectinib, brigatinib and lorlatinib in ALK-positive NSCLC. Its patent estate is commercially less diversified if protection depends heavily on one method-of-use patent rather than a long chain of composition, formulation and dosing patents.
What generic launch scenarios exist for ensartinib?
Scenario 1: Launch after patent expiry
The lowest-litigation scenario is an ANDA approval after expiration of all relevant listed patents and regulatory exclusivities.
Scenario 2: Paragraph IV launch
An ANDA applicant may challenge the listed patents and launch after a favorable court decision, settlement, dismissal or statutory litigation stay expiration.
Scenario 3: Skinny-label launch
A generic could omit patented indications from its label. This strategy would be difficult if the only commercially valuable use is ALK-positive NSCLC and the generic is expected to be prescribed for that indication.
Scenario 4: Authorized generic or settlement
The sponsor could license an authorized generic or settle with a challenger under an agreed entry date. Any settlement involving a Hatch-Waxman dispute would be subject to applicable FTC and DOJ scrutiny.[5]
What is the geographic coverage of the ensartinib patent estate?
US 9,255,087 has effect only in the United States. Foreign protection depends on corresponding national patents and their individual status.
Relevant jurisdictions include:
- United States;
- European Patent Convention states;
- China;
- Japan;
- South Korea;
- Canada;
- Australia; and
- Other markets where ensartinib is developed or commercialized.
A US patent does not block manufacture, sale or use outside the United States. Cross-border supply can still create US infringement issues where an infringing product is imported into, sold in or used in the United States.
Key Takeaways
- US 9,255,087 is an ensartinib method-of-treatment and ALK-inhibition patent.
- Claims 4 and 11 provide the clearest protection for ALK-positive NSCLC, the FDA-approved Ensacove indication.
- Claim 15 covers contacting ALK with ensartinib and is broader in activity than the patient-treatment claims.
- The patent does not, based on the quoted claims, protect the chemical composition, formulation or manufacturing process.
- The patent’s nominal term runs into approximately 2031, subject to patent-term adjustment or extension.
- Ensartinib is a small molecule, so generic ANDA litigation applies; biosimilar pathways do not.
- A Paragraph IV challenge could target breadth, enablement, written description, obviousness or noninfringement.
- The commercial strength of the patent depends on the complete ensartinib family, FDA Orange Book listings and any later formulation or dosing patents.
FAQs About US Patent 9,255,087 and Ensartinib
Does US 9,255,087 cover all ALK inhibitors?
No. It covers the specifically identified ensartinib molecule or a pharmaceutically acceptable salt. It does not cover crizotinib, alectinib, brigatinib, lorlatinib or other unrelated ALK inhibitors.
Can a generic sell ensartinib for colorectal cancer after omitting NSCLC from its label?
Potentially, but the answer depends on the Orange Book patents, the approved labeling, the proposed carve-out and evidence of induced infringement. Omitting one indication does not automatically eliminate liability under other method claims.
Does claim 15 cover laboratory research using ensartinib?
Claim 15 is drafted around contacting ALK with an effective amount of ensartinib. Its application to a particular research activity would depend on the activity, the identity of the ALK material and whether the claim limitations are met.
Is Ensacove protected by a biologic exclusivity period?
No. Ensacove contains ensartinib, a chemically synthesized small molecule. Biologics Price Competition and Innovation Act biosimilar exclusivity does not apply.
Can patent expiry alone permit immediate generic launch?
No. Generic entry also depends on FDA regulatory exclusivity, other Orange Book-listed patents, litigation outcomes, settlement terms and any patent-term adjustment or extension.
References
-
U.S. Food and Drug Administration. (2024). FDA approves ensartinib for ALK-positive non-small cell lung cancer. https://www.fda.gov/
-
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/
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U.S. Code, 21 U.S.C. § 355(j). Abbreviated new drug applications and patent certifications.
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Innovent Biologics. (2024). Ensartinib development and commercialization information. https://www.innoventbio.com/
-
Federal Trade Commission. (2023). Agreements filed with the Federal Trade Commission under the Medicare Prescription Drug, Improvement, and Modernization Act. https://www.ftc.gov/
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United States Patent and Trademark Office. (2016). U.S. Patent No. 9,255,087: Methods of treating cancer using inhibitors of ALK. https://patents.google.com/patent/US9255087B2/en
