U.S. Patent 10,966,984: Trilaciclib Combination-Therapy Claims, Exclusivity, and Patent Landscape
U.S. Patent No. 10,966,984 protects the use of a selective CDK4/6 inhibitor, understood from the claimed structure and the associated Cosela product to be trilaciclib, immediately before cytotoxic chemotherapy. The central limitation is timing: the CDK4/6 inhibitor must be administered no more than 24 hours before chemotherapy, with narrower claims covering four hours and 30 minutes or less.
The patent is a method-of-treatment patent, not a composition-of-matter patent. It does not prevent all manufacture, sale, or use of trilaciclib. Its commercial value depends on whether a competing product, clinical protocol, label, or treatment practice directs administration of trilaciclib within the claimed pre-chemotherapy windows.
What does U.S. Patent 10,966,984 protect?
The patent protects sequential administration of a selective CDK4/6 inhibitor followed by a chemotherapeutic agent in a human cancer patient.
The claimed sequence has four core elements:
- A human patient has cancer.
- The patient receives an effective amount of the claimed selective CDK4/6 inhibitor or a pharmaceutically acceptable salt.
- The patient receives chemotherapy.
- The CDK4/6 inhibitor is administered no more than 24 hours before chemotherapy.
The structure reproduced in the claims corresponds to trilaciclib, the active ingredient in G1 Therapeutics' Cosela. Cosela is an intravenous CDK4/6 inhibitor used to reduce the frequency of chemotherapy-induced myelosuppression in specified settings, rather than as a conventional antitumor cytotoxic agent.[1]
The patent therefore targets a treatment regimen in which trilaciclib is used as a transient cell-cycle inhibitor before chemotherapy. The commercial theory is that temporary CDK4/6 inhibition protects normal hematopoietic progenitor cells and immune cells from chemotherapy-associated damage while allowing the cytotoxic agent to treat the tumor.
How are the independent claims structured?
| Claim |
Protected subject matter |
Key timing limitation |
| 1 |
Human cancer treatment with the claimed CDK4/6 inhibitor plus chemotherapy |
No more than 24 hours before chemotherapy |
| 19 |
Treatment of triple-negative breast cancer with the same combination |
No more than 24 hours before chemotherapy |
Claim 1 is broad across cancer types and includes the chemotherapeutic agents listed in claim 3. Claim 19 is narrower as to disease because it is limited to triple-negative breast cancer, but it creates a separate independent infringement pathway.
The claims do not expressly require:
- A particular dose of trilaciclib.
- A particular route of administration.
- A particular chemotherapy dose or schedule.
- A demonstrated reduction in myelosuppression.
- A specific order of administration beyond the CDK4/6 inhibitor preceding chemotherapy.
- A particular treatment cycle or number of cycles.
- A particular tumor biomarker, except where the disease-dependent claims specify triple-negative breast cancer or HPV-positive head and neck cancer.
The absence of a dosing limitation expands the literal scope of the claims. The timing limitation remains the principal boundary.
What timing windows are protected?
Claims 1 and 19 establish the broadest timing window: administration of the CDK4/6 inhibitor about 24 hours or less before chemotherapy.
Claims 2 and 20 narrow that interval to about four hours or less. Claims 21 and 27 narrow it further to about one-half hour or less.
| Timing claim |
Practical scope |
| Claims 1 and 19 |
About 24 hours or less before chemotherapy |
| Claims 2 and 20 |
About four hours or less |
| Claims 21 and 27 |
About 30 minutes or less |
The nested structure is important. If the 24-hour limitation in claim 1 were challenged, claims 2 and 27 could remain relevant if the accused regimen falls within the narrower windows. A protocol using trilaciclib 30 minutes before chemotherapy could potentially implicate claims 1, 2, and 27, subject to claim construction and validity.
The term "about" creates a potential dispute at the boundary of each window. A court would likely assess the term in view of the specification, examples, pharmacology, and ordinary meaning in the relevant field. The claims do not define a fixed tolerance around 24 hours, four hours, or 30 minutes.
Which chemotherapy agents are covered?
Claim 3 covers the following agents and combinations:
- Etoposide
- Carboplatin
- Gemcitabine
- Topotecan
- Paclitaxel
- Docetaxel
- Doxorubicin
- Cisplatin
- Fluorouracil
Claims 13 through 18 separately claim etoposide, carboplatin, gemcitabine, topotecan, paclitaxel, and docetaxel. Claims 28 and 29 separately cover cisplatin and 5-fluorouracil.
For triple-negative breast cancer, claim 22 covers:
- Carboplatin
- Gemcitabine
- Paclitaxel
- Doxorubicin
- Cyclophosphamide
- Combinations of those agents
Claims 23 through 26 separately claim carboplatin, gemcitabine, paclitaxel, and doxorubicin. Claim 30 separately claims cyclophosphamide.
The claim set therefore reaches both platinum-based and non-platinum chemotherapy. It also covers combination regimens, which may be commercially significant because many oncology protocols use multi-agent chemotherapy.
Which cancers are covered?
| Claims |
Disease scope |
| Claim 4 |
Lung cancer |
| Claim 5 |
Breast cancer |
| Claim 6 |
HPV-positive head and neck cancer |
| Claim 7 |
Cervical cancer |
| Claim 8 |
Prostate cancer |
| Claim 9 |
Bladder cancer |
| Claim 10 |
Colorectal cancer |
| Claim 11 |
Small-cell lung cancer |
| Claim 12 |
Triple-negative breast cancer |
| Claims 19-30 |
Triple-negative breast cancer with specified chemotherapy |
Claim 1 is not limited to the listed cancers. The disease-specific claims provide narrower alternatives, while claim 19 independently targets triple-negative breast cancer.
The strongest commercial overlap is likely in small-cell lung cancer and triple-negative breast cancer, where chemotherapy regimens have historically created substantial myelosuppression risk and where Cosela's clinical positioning has been concentrated.
What are the strongest and weakest claim limitations?
Strongest scope
The broadest commercial protection comes from the combination of:
- The claimed trilaciclib structure or salt.
- Any human cancer.
- Any effective amount.
- Any chemotherapy agent within the claim language.
- Administration within approximately 24 hours before chemotherapy.
The lack of a dose limitation makes simple regimen redesign difficult. A competitor cannot necessarily avoid the patent by changing the trilaciclib dose while retaining the same sequence and timing.
Narrower but commercially important scope
The narrower claims covering 30 minutes or less may align closely with actual Cosela administration protocols. These claims may be easier to prove when treatment records show a standard infusion immediately before chemotherapy.
The disease-specific claims can also strengthen enforcement when the patient's diagnosis clearly falls within the listed category, particularly triple-negative breast cancer and small-cell lung cancer.
Potentially vulnerable limitations
Several terms may create validity or infringement disputes:
- "Selective CDK4/6 inhibitor"
- "Effective amount"
- "About 24 hours or less"
- "About 4 hours or less"
- "About ½ hour or less"
- The scope of the structural formula and pharmaceutically acceptable salts
- The breadth of the cancer and chemotherapy combinations
A validity challenge could focus on obviousness based on prior knowledge that CDK4/6 inhibition can alter cell-cycle progression and that chemotherapy sequencing affects normal-tissue protection. The patentee's strongest response would be evidence of unexpected results, clinically meaningful protection, or a non-obvious timing relationship.
What is the FDA and Orange Book status?
Cosela, containing trilaciclib, was approved by the FDA on February 12, 2021, under NDA 214837.[1] Its approved use is to decrease the frequency of chemotherapy-induced bone marrow suppression in adult patients when administered before a platinum/etoposide-containing regimen, a topotecan-containing regimen, or a topotecan-containing regimen combined with a platinum agent, and in adults with extensive-stage small-cell lung cancer receiving a platinum/etoposide-containing regimen or topotecan-containing regimen.[1]
| Regulatory item |
Status |
| Product |
Cosela |
| Active ingredient |
Trilaciclib |
| Sponsor |
G1 Therapeutics, Inc. |
| NDA |
214837 |
| FDA approval |
February 12, 2021 |
| Regulatory type |
New molecular entity product approval |
| Primary commercial use |
Myelopreservation before chemotherapy |
Patent listing should be evaluated against the current FDA Orange Book patent record for NDA 214837. U.S. Patent 10,966,984 is a method-of-treatment patent directed to the approved clinical concept of administering trilaciclib before chemotherapy. Its relevance to an abbreviated new drug application depends on the listed patent status, the proposed generic label, and whether the applicant submits a Paragraph IV certification.
When does U.S. Patent 10,966,984 lose exclusivity?
The patent's estimated ordinary expiration is March 3, 2036, based on the patent family's reported priority framework. The effective expiration date must be read with the USPTO patent-term-adjustment calculation and any applicable patent-term extension record.[2]
The regulatory and patent timelines are separate:
| Exclusivity right |
Approximate end date |
| FDA five-year new chemical entity exclusivity |
February 12, 2026 |
| U.S. Patent 10,966,984 |
Approximately March 3, 2036, before any adjustment |
| Earliest ordinary ANDA approval absent Paragraph IV timing |
After NCE exclusivity ends |
| Potential generic launch |
Dependent on patent certifications, litigation, settlement, and claim validity |
NCE exclusivity prevents FDA approval of an ANDA or certain 505(b)(2) applications during the exclusivity period. It does not prevent a Paragraph IV filing after the statutory filing date or prevent patent litigation before the NCE period ends.
What Paragraph IV risks exist?
A generic applicant seeking a trilaciclib product could face several certification issues:
- The applicant could certify that the listed patent has expired.
- It could certify that the patent is not infringed.
- It could assert that the patent is invalid or unenforceable under Paragraph IV.
- It could seek a label that omits the patented method, if a legally sufficient skinny-label strategy is available.
The principal risk is that a generic product label or proposed use could expressly direct administration of trilaciclib within 24 hours, four hours, or 30 minutes before chemotherapy. Such language would closely track the claims.
A non-infringing label would be more difficult if the approved product's clinical use inherently requires pre-chemotherapy administration. The Hatch-Waxman analysis would then turn on the proposed label, prescribing information, marketing activities, and whether the patented method is an approved use that can be carved out.
Which companies are challenging the patent?
The patent number and claim text alone do not establish a Paragraph IV filing, ANDA applicant, district-court complaint, or settlement agreement. No challenger or settlement party should be attributed to this patent without a corresponding FDA, USPTO, PACER, or court record.
The likely competitive set includes generic-drug companies capable of developing an intravenous trilaciclib product and oncology companies developing alternative myeloprotective approaches. The principal branded CDK4/6 competitors, palbociclib, ribociclib, and abemaciclib, are not direct substitutes for Cosela's pre-chemotherapy myelopreservation use. Their labels and dosing schedules are directed primarily to antitumor treatment, especially hormone-receptor-positive, HER2-negative breast cancer.
Is there biosimilar risk?
There is no biosimilar pathway for trilaciclib because trilaciclib is a small-molecule drug. The relevant competitive pathway is an ANDA for a generic drug or a 505(b)(2) application for a modified product or new use.
The key barriers are:
- Injectable product development.
- Demonstration of pharmaceutical equivalence.
- Manufacturing and sterile-fill capability.
- Clinical-use labeling.
- Orange Book patent certifications.
- Potential method-of-use litigation.
- Commercial scale in a specialized oncology market.
The absence of biosimilar risk does not eliminate competition. It shifts the risk toward small-molecule generic entry and label-based patent disputes.
How strong is the patent estate?
U.S. Patent 10,966,984 is commercially meaningful but narrower than a composition-of-matter patent.
| Estate characteristic |
Assessment |
| Patent type |
Method of treatment |
| Product dependence |
High |
| Timing protection |
Strong if treatment occurs within claimed windows |
| Dose protection |
Limited, because claims do not specify a dose |
| Disease coverage |
Broad in claim 1; narrowed disease claims provide fallback positions |
| Chemotherapy coverage |
Broad but expressly enumerated |
| Generic vulnerability |
Moderate to high if a label directs the patented sequence |
| Biosimilar exposure |
None |
| Geographic reach |
United States only |
| Manufacturing protection |
None apparent from the supplied claims |
The patent does not directly protect the chemical composition of trilaciclib, its synthesis, crystalline form, formulation, or manufacturing process. Those rights, if any, must be analyzed separately in the relevant patent family and Orange Book records.
What generic launch scenarios exist?
Scenario 1: Label tracks the patented use
A generic label expressly directs trilaciclib administration before chemotherapy. This creates the highest infringement and litigation risk and could trigger a Paragraph IV notice and a 30-month stay if statutory requirements are met.
Scenario 2: Skinny label
The applicant omits the patented method from the label. The feasibility of this strategy depends on whether the remaining approved uses can be marketed without encouraging the patented administration sequence and whether the FDA permits the carve-out.
Scenario 3: Post-expiration launch
The applicant waits for patent expiry or settlement-based permission. This minimizes litigation risk but may delay entry until approximately 2036, subject to patent-term adjustments and other patents.
Scenario 4: Invalidity or non-infringement challenge
The applicant argues that the proposed regimen falls outside the timing window, uses a different active ingredient, does not satisfy the structural limitation, or that the claims are invalid over prior art.
What patent litigation and settlement issues matter?
The critical litigation questions are likely to be:
- Whether the claimed structure covers the proposed active ingredient and salt.
- Whether "about" includes the accused administration interval.
- Whether a product label induces physicians to practice the patented method.
- Whether administration more than 24 hours before chemotherapy avoids claim 1.
- Whether a treatment protocol using a different CDK4/6 inhibitor avoids the structural limitation.
- Whether prior art disclosed the same drug sequence and timing.
- Whether broad cancer coverage is enabled across all claimed disease categories.
A settlement could establish a licensed launch date before patent expiry, impose label restrictions, or allow launch for selected indications. No settlement terms should be inferred from the patent claims.
What is the geographic coverage?
U.S. Patent 10,966,984 provides U.S. rights only. International protection requires separate analysis of the patent family in jurisdictions such as Europe, Japan, China, Canada, and Australia. Foreign counterparts may differ in:
- Claim scope.
- Patent expiration.
- Patent-term adjustment or supplementary protection.
- National validity.
- Regulatory linkage.
- Generic litigation procedures.
- Enforceability of method-of-treatment claims.
A global launch assessment cannot rely on the U.S. patent alone.
Key Takeaways
- U.S. Patent 10,966,984 protects trilaciclib-based treatment administered before chemotherapy.
- The broadest timing limitation is about 24 hours or less before chemotherapy.
- Narrower claims cover four hours or less and 30 minutes or less.
- The claims cover multiple cytotoxic agents, including etoposide, carboplatin, gemcitabine, topotecan, paclitaxel, docetaxel, doxorubicin, cisplatin, fluorouracil, and cyclophosphamide.
- The patent reaches broad cancer categories, with specific claims for small-cell lung cancer and triple-negative breast cancer.
- The patent is a method patent, not a composition, formulation, or manufacturing patent.
- Cosela was FDA-approved on February 12, 2021, under NDA 214837.
- FDA NCE exclusivity runs approximately through February 12, 2026.
- The patent's estimated ordinary expiration is approximately March 3, 2036, before any patent-term adjustment.
- Generic risk is primarily an ANDA and Paragraph IV issue, not a biosimilar issue.
- The principal commercial vulnerability is a label-based challenge directed to the timing limitation, structural identity, and validity of the treatment claims.
FAQs
Does U.S. Patent 10,966,984 protect Cosela itself?
No. The supplied claims protect specified methods of using the claimed selective CDK4/6 inhibitor before chemotherapy. They do not, by themselves, establish composition-of-matter, formulation, or manufacturing protection for trilaciclib.
Can a competitor avoid the patent by administering trilaciclib more than 24 hours before chemotherapy?
Potentially, if the actual regimen falls outside the properly construed claim timing and does not satisfy another claimed sequence. The clinical and legal effect depends on the full protocol and claim construction.
Does using a different CDK4/6 inhibitor avoid infringement?
The claim requires the specific structural formula shown in the patent. A different CDK4/6 inhibitor would generally avoid literal infringement of the structural limitation, subject to any applicable doctrine-of-equivalents analysis.
Is Cosela protected by a biosimilar exclusivity period?
No. Trilaciclib is a small molecule. Competition would proceed through generic-drug or 505(b)(2) pathways rather than the biosimilar pathway.
What is the most important claim for a generic launch analysis?
Claim 1 is the central claim because it covers any human cancer treatment using the claimed inhibitor and chemotherapy within approximately 24 hours. Claims 2 and 27 may create additional exposure for regimens administered within four hours or 30 minutes.
References
-
U.S. Food and Drug Administration. (2021). Cosela (trilaciclib) prescribing information. FDA.
-
United States Patent and Trademark Office. (2021). U.S. Patent No. 10,966,984, Methods of treating cancer using a CDK4/6 inhibitor. USPTO.
-
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.
-
U.S. Food and Drug Administration. (1984). Drug Price Competition and Patent Term Restoration Act of 1984. FDA.
-
U.S. Food and Drug Administration. (2021). NDA 214837: Cosela, trilaciclib. FDA.
