United States Patent 8,741,929: Lenalidomide Mantle Cell Lymphoma Claims, Exclusivity, Litigation, and Generic Risk
U.S. Patent No. 8,741,929 protects a dosing regimen for lenalidomide, marketed as Revlimid, in patients with relapsed or refractory mantle cell lymphoma. The core limitation is 5 mg to 25 mg once daily for 21 consecutive days followed by seven days of rest in a 28-day cycle, repeated for additional cycles. The patent also covers oral capsules or tablets, selected dose levels, rituximab combinations, corticosteroids, proteasome inhibitors, and other second active agents.
The patent is a method-of-use patent, not a basic composition-of-matter patent. Its commercial significance depends on the relationship between the patented mantle cell lymphoma indication, FDA labeling, Orange Book listings, generic carve-outs, and separate lenalidomide composition and formulation patents.
What drug and disease are covered by U.S. Patent 8,741,929?
The claimed active ingredient is lenalidomide, identified in the claims by its chemical name:
3-(4-amino-1-oxo-1,3-dihydro-isoindol-2-yl)-piperidine-2,6-dione.
The claims cover treatment of mantle cell lymphoma, particularly disease that is:
- Relapsed;
- Refractory to conventional therapy; or
- Both relapsed and refractory.
The covered regimen corresponds closely to the approved Revlimid dosing schedule for mantle cell lymphoma: 25 mg orally once daily on Days 1 through 21 of repeated 28-day cycles, generally continued until disease progression or unacceptable toxicity, subject to dose modification.[1]
The patent does not broadly claim every use of lenalidomide in every cancer. It is directed to a specific hematologic malignancy, a defined dose range, a defined intermittent schedule, and specified combination therapies.
What are the independent claims in Patent 8,741,929?
The patent has two principal independent method claims.
| Claim |
Core subject matter |
Principal limitations |
| 1 |
Lenalidomide monotherapy |
Relapsed, refractory, or relapsed and refractory mantle cell lymphoma; 5 mg to 25 mg per day; 21 days on and seven days off; repeated cycles |
| 11 |
Lenalidomide combination therapy |
Same lenalidomide regimen plus a second active agent administered in repeated treatment and rest periods |
Claim 1 is the principal monotherapy claim. Claim 11 is broader in one respect because it expressly covers combination therapy with a defined class of second agents.
Claim 11 identifies the following categories of second active agents:
- Hematopoietic growth factors;
- Cytokines;
- Anticancer agents;
- Antibiotics;
- COX-2 inhibitors;
- Corticosteroids;
- Rituximab; and
- Combinations of those agents.
Claim 11 does not require a specific second agent. Claims 12 through 14 narrow the combination to rituximab, dexamethasone, or prednisone. Claim 24 further narrows the anticancer agent to a proteasome inhibitor.
How do the dependent claims narrow the patent scope?
The dependent claims create multiple overlapping positions around the core regimen.
| Claims |
Limitation |
| 2 |
Dose of approximately 5, 10, 15, 20, or 25 mg per day |
| 3 |
Dose of approximately 10, 15, 20, or 25 mg per day |
| 4 |
Dose of approximately 25 mg per day |
| 5-7 |
Enantiomerically pure lenalidomide, including S or R enantiomer |
| 8-9 |
Oral administration in capsule or tablet form |
| 10 |
Rituximab at 375 mg/m² by weekly intravenous infusion |
| 12-14 |
Rituximab, dexamethasone, or prednisone as the second active agent |
| 15-20 |
Specific dose levels from 5 mg through 25 mg per day |
| 21-22 |
Oral capsule or tablet administration |
| 23 |
Rituximab at 375 mg/m² by weekly intravenous infusion |
| 24 |
A proteasome inhibitor as the anticancer agent |
The narrower claims may be more commercially relevant than the broad claims because the FDA-approved mantle cell lymphoma regimen uses 25 mg daily on Days 1 through 21 of a 28-day cycle. Claims 4 and 20 directly target that dose.
What regimen does Patent 8,741,929 cover?
The core regimen has four required components:
- A human patient with mantle cell lymphoma;
- Relapsed, refractory, or relapsed and refractory disease;
- Lenalidomide at approximately 5 mg to 25 mg per day; and
- Treatment for 21 days followed by seven days of rest in a 28-day cycle, with the cycle repeated.
The schedule is narrower than a general claim to administering lenalidomide. A use involving continuous daily administration, a different cycle length, or a materially different treatment schedule would require separate infringement analysis.
The claims use “about,” which gives the dose limitations some tolerance around the stated amounts. The precise scope would depend on claim construction, the specification, prosecution history, and the evidence concerning clinically meaningful dose variation.
What formulations are protected by Patent 8,741,929?
The patent includes claims directed to oral administration and administration in capsule or tablet form. These claims are formulation-adjacent method claims rather than claims to a particular excipient system, particle size, coating, dissolution profile, or manufacturing process.
The patent therefore protects use of an oral lenalidomide capsule or tablet when it is administered under the claimed mantle cell lymphoma regimen. It does not, based on the supplied claims, independently claim:
- A specific capsule shell;
- A particular excipient combination;
- A defined dissolution profile;
- A sustained-release formulation;
- A specific polymorph;
- A manufacturing process;
- A particular packaging system; or
- A standalone pharmaceutical composition.
Separate lenalidomide composition, formulation, process, and distribution-control patents may create additional barriers.
What method-of-use claims are protected?
Patent 8,741,929 contains several method-of-use layers.
Disease-specific use
The claims are limited to mantle cell lymphoma. The disease limitation is central. Use in multiple myeloma, myelodysplastic syndromes, diffuse large B-cell lymphoma, or another cancer would not fall within the literal scope of the supplied claims solely because lenalidomide was administered.
Disease-status limitation
The patient must have relapsed, refractory, or relapsed and refractory disease to conventional therapy. This limitation narrows the claims relative to an indication covering newly diagnosed or treatment-naive patients.
Schedule limitation
The 21-days-on, seven-days-off schedule is required. The repeated-cycle requirement also matters. A single 21-day treatment course without repetition could raise a noninfringement argument, depending on the claim construction and facts.
Combination-use limitations
Claims 10 through 14, 23, and 24 cover combinations with rituximab, corticosteroids, and proteasome inhibitors. The rituximab claims specify 375 mg/m² by weekly intravenous infusion. Claim 24 reaches combination use with a proteasome inhibitor without identifying a particular proteasome inhibitor in the supplied claim text.
What is the patent expiration date?
The patent is generally associated with a December 28, 2027 expiration date based on its priority and patent-term framework. The precise enforceable expiration must be confirmed against the USPTO patent-term adjustment record, any patent-term extension, terminal disclaimer, and Orange Book data.
The patent was granted on June 3, 2014. A grant date does not determine expiration. For a U.S. utility patent filed after June 8, 1995, the ordinary term is generally 20 years from the earliest effective nonprovisional filing date, subject to adjustments under 35 U.S.C. §§ 154 and 156.[2]
| Event |
Date or status |
| Patent |
U.S. Patent No. 8,741,929 |
| Grant date |
June 3, 2014 |
| Subject |
Lenalidomide treatment of mantle cell lymphoma |
| Expected nominal expiration |
December 28, 2027 |
| Patent category |
Method-of-use |
| Key product |
Revlimid |
| Relevant FDA indication |
Relapsed or refractory mantle cell lymphoma after prior therapy, including bortezomib |
What is the Orange Book status of Patent 8,741,929?
The patent has been associated with the Revlimid regulatory and patent estate. Orange Book treatment of method-of-use patents depends on whether the patent is submitted for an approved indication and how FDA assigns the corresponding use code.
A method-of-use listing can affect an abbreviated new drug application even when composition patents have expired or are subject to settlement-based launch dates. An ANDA applicant may attempt to avoid the method patent through:
- Paragraph IV certification and patent litigation;
- A section viii statement, also called a skinny label, omitting the patented indication; or
- A non-infringement or invalidity position based on the proposed label and product use.
The practical value of the patent depends on whether the generic label includes mantle cell lymphoma treatment and whether the generic manufacturer can reasonably prevent its product from being used for the patented indication.
When does lenalidomide lose exclusivity?
Lenalidomide exclusivity is controlled by several overlapping rights, not by Patent 8,741,929 alone.
| Exclusivity layer |
Commercial function |
| Composition-of-matter patents |
Protect lenalidomide itself and can delay broad generic entry |
| Method-of-use patents |
Protect particular diseases, doses, schedules, or combinations |
| Formulation patents |
Protect dosage-form or release characteristics |
| FDA orphan exclusivity |
May protect a specific rare-disease indication for a defined period |
| Pediatric exclusivity |
May add six months to eligible listed patents and exclusivity |
| Settlement agreements |
Can establish agreed generic launch dates before patent expiration |
| REMS and distribution controls |
May complicate generic market entry and product access |
Revlimid generic entry began in the United States under settlement and license arrangements rather than through unrestricted market entry across all indications. Generic lenalidomide availability therefore does not establish freedom to market for the patented mantle cell lymphoma indication.
Which companies have challenged or licensed Revlimid patents?
The Revlimid patent estate has been challenged by multiple generic manufacturers, including companies such as Natco, Teva, Dr. Reddy’s Laboratories, and Cipla. The principal commercial disputes involved the core lenalidomide patent estate and negotiated launch dates.
Natco and Celgene entered into a settlement and license arrangement that allowed limited generic lenalidomide entry before expiration of major patent rights, subject to volume and timing restrictions.[3] Other generic manufacturers entered related agreements or pursued ANDA litigation involving Revlimid patents.
The existence of a generic settlement does not mean that every Revlimid method patent was invalidated. Settlements commonly preserve patent rights while authorizing entry under defined conditions.
What Paragraph IV risks apply to Patent 8,741,929?
A Paragraph IV challenge would assert that the patent is invalid, unenforceable, or not infringed. The principal risk categories are as follows.
Anticipation
A challenger could argue that prior art disclosed lenalidomide treatment of mantle cell lymphoma using the claimed dose and schedule. The defense would focus on whether a single prior-art reference disclosed all limitations, including:
- Relapsed or refractory mantle cell lymphoma;
- The 5 mg to 25 mg dose range;
- The 21/7 cycle;
- Repeated cycles; and
- Any claimed combination therapy.
Obviousness
Obviousness is likely the more important validity issue. A challenger could combine prior art concerning:
- Lenalidomide pharmacology;
- Earlier multiple myeloma dosing;
- Mantle cell lymphoma biology;
- Conventional 21/7 dosing schedules;
- Rituximab combinations; and
- Proteasome inhibitor therapy.
The patent holder would likely argue that the specific regimen produced clinically meaningful results in a difficult-to-treat population and that the prior art did not provide a reasonable expectation of success.
Written description and enablement
The claims cover a broad 5 mg to 25 mg dose range and multiple second-agent categories. A challenger could test whether the specification adequately supports and enables the full range, each listed combination, and both enantiomers.
Claim construction
The meaning of “about,” “conventional therapy,” “relapsed,” “refractory,” “for a period of time followed by a period of rest,” and “repeating” could materially affect infringement and validity.
Induced infringement
Even if an ANDA label omits mantle cell lymphoma, a patent holder could assess whether promotional materials, treatment protocols, distribution practices, or physician instructions encourage use for the patented indication. The risk is fact-specific and generally greater when the generic product is actively promoted for the indication.
How strong is the patent estate?
Patent 8,741,929 has a focused but commercially relevant claim set.
| Strength factor |
Assessment |
| Clinical alignment |
Strong, because the 25 mg, 21/7 schedule aligns with the approved MCL regimen |
| Disease limitation |
Narrows enforcement to mantle cell lymphoma |
| Dose coverage |
Strong for the approved 25 mg regimen; broader range creates more validity exposure |
| Combination coverage |
Broad in claim 11, but vulnerable to enablement and obviousness arguments |
| Formulation coverage |
Limited to oral capsule or tablet use under the method |
| Composition protection |
None in the supplied claims |
| Generic work-around |
Possible through label carve-out, off-label-use controls, or noninfringement |
| Expiration value |
Material through approximately December 2027, subject to official term verification |
The strongest commercial claims are likely claims 1, 4, 8, 9, 11, 12, 20, 21, 22, and 24 when a generic product is labeled for relapsed or refractory mantle cell lymphoma and the label reflects 25 mg oral dosing on a 21/7 schedule.
The broadest claims are not necessarily the strongest. Claim 11 covers a wide universe of second agents, but its breadth can create greater exposure to prior-art, written-description, enablement, and obviousness challenges.
What generic launch scenarios exist?
Scenario 1: Full indication label
A generic applicant includes mantle cell lymphoma in its label. This creates the clearest infringement exposure for claims 1 and 4, especially if the label specifies 25 mg on Days 1 through 21 of each 28-day cycle.
Scenario 2: Skinny label
The applicant omits mantle cell lymphoma under a section viii statement. This may reduce direct inducement exposure, although it does not eliminate all litigation risk.
Scenario 3: Licensed entry
The applicant launches under a Celgene or Bristol Myers Squibb settlement license. Entry timing, volume, and permitted indications would be controlled by the agreement.
Scenario 4: Alternative regimen
The generic label uses a different dose or schedule. This may avoid literal infringement but could create clinical and regulatory disadvantages if the alternative regimen is not aligned with the reference product label.
Scenario 5: Post-expiration entry
After expiration, the patent no longer blocks the claimed MCL regimen, but other valid patents, regulatory exclusivities, contractual restrictions, or product-supply requirements could remain relevant.
What manufacturing and intellectual-property barriers remain?
Patent 8,741,929 itself does not create a major manufacturing barrier because it is a treatment-method patent. Manufacturing risk is more likely to arise from separate rights involving:
- Lenalidomide synthesis;
- Polymorphs and solid-state forms;
- Pharmaceutical compositions;
- Capsule or tablet manufacture;
- Purity specifications;
- Process impurities;
- Packaging and distribution controls; and
- REMS-related supply procedures.
Lenalidomide is a small molecule, so biosimilar approval is not relevant. Generic applicants use the ANDA pathway rather than the biosimilar pathway. The principal regulatory questions are bioequivalence, labeling, patent certification, and any applicable risk-management requirements.
What is the revenue exposure from this patent?
Revlimid generated multibillion-dollar annual revenue for Celgene and later Bristol Myers Squibb. Bristol Myers Squibb reported Revlimid revenue of approximately $6.1 billion in 2023, with continued decline expected as generic competition expanded.[4]
Public company reporting generally does not isolate revenue attributable solely to mantle cell lymphoma. The MCL portion of Revlimid revenue is therefore not separately quantifiable from standard financial disclosures.
The patent’s commercial value is greater than the MCL indication’s standalone sales contribution because the patent can affect:
- The permitted scope of generic labels;
- ANDA litigation strategy;
- Settlement economics;
- Indication-specific market segmentation; and
- The timing of broad substitution in hematologic oncology.
How does Patent 8,741,929 compare with the broader Revlimid patent estate?
| Patent category |
Scope |
Strategic importance |
| Composition patents |
Lenalidomide molecule and related compounds |
Highest importance for broad generic entry |
| MCL method patent |
5-25 mg, 21/7 schedule, relapsed or refractory MCL |
Important for indication-specific labeling |
| Formulation patents |
Tablets, capsules, excipients, release, or composition |
Can delay or complicate product design |
| Combination patents |
Lenalidomide with rituximab, corticosteroids, or proteasome inhibitors |
Relevant to treatment protocols |
| Manufacturing patents |
Synthesis and purification |
Can require process redesign or licensing |
| Distribution rights and agreements |
Supply, REMS, and settlement restrictions |
Can affect practical launch timing |
Patent 8,741,929 is not a substitute for the composition patent estate. It is a targeted indication patent that can retain value after some broader rights have expired, particularly where the reference label includes the patented MCL regimen.
Key Takeaways
- U.S. Patent 8,741,929 claims lenalidomide treatment of relapsed or refractory mantle cell lymphoma.
- The central regimen is 5 mg to 25 mg daily for 21 days followed by seven days of rest in a repeated 28-day cycle.
- The 25 mg dose claims closely track the FDA-approved Revlimid MCL regimen.
- The patent covers monotherapy and combinations with rituximab, dexamethasone, prednisone, proteasome inhibitors, and other agents.
- Claims 8, 9, 21, and 22 cover oral capsule or tablet administration, but not a specific excipient or manufacturing platform.
- The expected patent expiration is December 28, 2027, subject to confirmation from the USPTO and Orange Book records.
- Generic risk is greatest when an ANDA label includes mantle cell lymphoma and the 25 mg, 21/7 dosing schedule.
- A section viii carve-out or licensed launch may reduce direct infringement exposure.
- The patent does not cover biosimilars because lenalidomide is a small-molecule drug regulated through the generic pathway.
- The principal validity risks are obviousness, written description, enablement, anticipation, and construction of the dose and treatment-schedule terms.
FAQs About U.S. Patent 8,741,929
Does Patent 8,741,929 cover lenalidomide for multiple myeloma?
No. The supplied claims are limited to mantle cell lymphoma. Use in multiple myeloma would require analysis of other Revlimid patents and regulatory claims.
Does the patent cover lenalidomide doses below 5 mg?
Not under the supplied independent claims. The claimed range begins at approximately 5 mg per day.
Does a generic lenalidomide product automatically infringe this patent?
No. Infringement depends on the approved label, promotional conduct, actual use, and whether the product is authorized or encouraged for the claimed MCL regimen.
Is rituximab required for infringement?
No. Claim 1 covers lenalidomide monotherapy. Rituximab is a limitation in dependent claim 10 and in combination claims such as claims 11, 12, and 23.
Does the patent claim the manufacture of Revlimid capsules?
No. The supplied claims are treatment-method claims. They cover administering oral lenalidomide in a capsule or tablet under the specified MCL regimen, not manufacturing the dosage form itself.
Sources
- U.S. Food and Drug Administration. (2024). Revlimid (lenalidomide) prescribing information.
- United States Patent and Trademark Office. (2014). U.S. Patent No. 8,741,929, Methods of treating mantle cell lymphoma.
- U.S. District Court, District of New Jersey. (2015). Celgene Corp. v. Natco Pharma Ltd., settlement and patent litigation materials concerning lenalidomide.
- Bristol Myers Squibb. (2024). 2023 annual report.
