United States Drug Patent 7,410,656: Claims, Scope, Expiration, and Patent Landscape for Angeloyl-Substituted Ingenanes

U.S. Patent No. 7,410,656 protects methods of treating neoplastic disease with isolated angeloyl-substituted ingenane compounds, with a specific claim to 20-O-acetyl-ingenol-3-angelate. The patent is method-of-use focused. It does not broadly claim every ingenane compound, a composition containing the compound, a manufacturing process, or a formulation.

The commercial relevance is narrower than the claim language may suggest. Ingenol mebutate, the active ingredient formerly marketed as Picato, is ingenol 3-angelate rather than 20-O-acetyl-ingenol-3-angelate. It may fall within the broadest language of claim 1 depending on claim construction, but it is not the express compound named in claim 3. Picato received FDA approval for actinic keratosis and was withdrawn from the U.S. market in 2020 after regulatory concerns regarding skin-cancer risk.[2,3]

What does U.S. Patent 7,410,656 claim?

The patent claims a therapeutic method comprising administration of an isolated angeloyl-substituted ingenane to inhibit proliferative activity in neoplastic cells.

Claim	Subject matter	Scope
1	Administration of an isolated angeloyl-substituted ingenane to inhibit neoplastic-cell proliferation	Broad independent method claim
2	Claim 1 compound with an acylated substitution on or at C-20	Species and subgenus limitation
3	20-O-acetyl-ingenol-3-angelate	Narrow compound-specific method claim
4	Claim 1 treatment where neoplastic cells occur in cancer or a tumor	Disease-context limitation
5	Skin cancer, malignant melanoma, Merkel cell carcinoma, squamous-cell carcinoma, basal-cell carcinoma, or solar keratosis	Cutaneous and dermatologic indications
6	Solid tumor, lung, colon, prostate, cervical, or breast cancer	Systemic and solid-tumor indications

The claim set has a conventional dependency structure. Claim 1 establishes the core genus. Claim 2 narrows the compound class by adding C-20 acylation. Claim 3 identifies one compound. Claims 4 through 6 narrow the disease setting.

What compound is protected by claim 3?

Claim 3 specifically covers a method using 20-O-acetyl-ingenol-3-angelate. Structurally, the compound contains:

An ingenane diterpene scaffold.
An angeloyl ester at the 3-position.
An acetyl substituent at the 20-position.

The 20-O-acetyl group differentiates the claimed molecule from ingenol 3-angelate, also known as ingenol mebutate. Ingenol mebutate has an angelate substituent at C-3 but does not have the additional 20-O-acetyl substitution recited in claim 3.

The distinction matters for product clearance. A product containing ingenol mebutate would not infringe claim 3 merely because it contains an angeloylated ingenane. A potential infringement theory would instead need to rely on claim 1, or on claim 2 if the accused compound has the required C-20 acylation.

How should claim 1 be construed?

Claim 1 has four operative limitations:

A method.
Inhibition of proliferative activity of neoplastic cells.
Administration to a subject in need.
Administration of a therapeutically effective amount of an isolated angeloyl-substituted ingenane.

The claim is not a compound claim. It does not prevent all manufacture, sale, or possession of an angeloyl-substituted ingenane. Liability generally turns on use, inducement, contributory infringement, or another theory connected to the claimed therapeutic method.

Meaning of "angeloyl-substituted ingenane"

The phrase identifies an ingenane compound bearing an angeloyl substituent. The broadest plausible reading may include ingenol 3-angelate, although the patent’s specification, examples, prosecution history, and chemical definitions would control the final construction.

The term does not necessarily cover:

Ingenane derivatives without an angeloyl group.
Tigliane or daphnane compounds that lack the required ingenane structure.
Compounds with only an unrelated acyl group.
Mixtures that do not contain an isolated compound.
A prodrug lacking the claimed structural relationship.

Meaning of "isolated compound"

"Isolated compound" distinguishes the claimed therapeutic agent from a crude plant extract or an uncharacterized natural mixture. A commercial product containing a purified active ingredient would likely satisfy this limitation if the active ingredient meets the structural definition.

The limitation may create a design-around path for products based on:

A standardized but non-isolated botanical extract.
A chemically modified derivative lacking an angeloyl substituent.
A different diterpene scaffold.
A formulation in which the administered active substance does not meet the claim’s structural requirements.

Those approaches would raise separate infringement and enablement questions. The claim does not automatically cover every plant-derived preparation containing related ingenane compounds.

What cancer indications are covered?

Claims 5 and 6 divide the disease coverage into dermatologic and systemic indications.

Dermatologic indications

Claim 5 expressly covers:

Skin cancer.
Malignant melanoma.
Merkel cell carcinoma.
Squamous-cell carcinoma.
Basal-cell carcinoma.
Solar keratosis, generally referred to as actinic keratosis.

The inclusion of solar keratosis is commercially important because it overlaps with the initial FDA-approved use of ingenol mebutate. The FDA approved Picato gel for topical treatment of actinic keratosis in 2012.[2]

The claim language does not limit treatment to topical administration. A topical product may be the most commercially relevant embodiment for skin disease, but the claims do not expressly recite a topical dosage form, concentration, vehicle, treatment schedule, or application site.

Solid and systemic tumors

Claim 6 covers:

Solid tumors generally.
Lung cancer.
Colon cancer.
Prostate cancer.
Cervical cancer.
Breast cancer.

Claim 6 is broader in disease context than a dermatology-only product patent. It may reach systemic or localized administration, depending on the specification and claim construction. It does not, however, claim every cancer indication unless the accused use falls within claim 1’s broader neoplastic-cell language or claim 4’s cancer-or-tumor limitation.

What formulations are protected by U.S. Patent 7,410,656?

The patent claims methods and compounds used in those methods. It does not contain an express formulation claim in the six claims supplied.

The claims therefore do not specifically claim:

A gel.
A cream.
An ointment.
A solution.
A suspension.
A transdermal patch.
A liposomal formulation.
A nanoparticle formulation.
A particular excipient system.
A specific concentration or dosing regimen.

A formulation could still be relevant to infringement if it delivers the claimed compound for a claimed therapeutic purpose. The absence of a formulation limitation means that the method claims may read on multiple dosage forms, but only when the compound, disease context, administration, and therapeutic-purpose limitations are met.

Separate formulation patents may provide stronger protection for a commercial product than this patent. For ingenol mebutate products, the principal commercial and regulatory patent analysis has historically involved product composition, topical gel formulations, dosage strengths, and methods of treating actinic keratosis rather than 20-O-acetyl-ingenol-3-angelate specifically.

Is 20-O-acetyl-ingenol-3-angelate the same as ingenol mebutate?

No. The compounds are structurally distinct.

Attribute	20-O-acetyl-ingenol-3-angelate	Ingenol mebutate
Core scaffold	Ingenane	Ingenane
C-3 substituent	Angeloyl	Angeloyl
C-20 substituent	Acetyl	No corresponding 20-O-acetyl group
Expressly recited in claim 3	Yes	No
Historical FDA product	No identified approved product	Picato
Primary historical indication	Antineoplastic research and claimed cancer uses	Actinic keratosis
U.S. commercial status	No established approved product	Picato withdrawn in 2020

Ingenol mebutate may be relevant to claim 1 because claim 1 is not limited to the C-20-acetyl species. Whether it falls within claim 1 depends on the proper construction of "angeloyl-substituted ingenane" and the other claim elements.

What is the FDA status of the claimed compounds?

No FDA-approved product based on 20-O-acetyl-ingenol-3-angelate is identified in the principal FDA drug-label and approval records associated with ingenane therapies.

Ingenol mebutate was approved as Picato gel under NDA 202-379 for actinic keratosis. The product was marketed in the United States in 0.015% and 0.05% topical gel strengths. The FDA later announced withdrawal of approval after safety concerns involving increased occurrence of skin malignancies in treated areas.[2,3]

The FDA withdrawal affected ingenol mebutate’s commercial position. It did not, by itself, invalidate U.S. Patent 7,410,656 and did not establish that ingenol mebutate infringed the patent.

When did U.S. Patent 7,410,656 lose exclusivity?

U.S. Patent No. 7,410,656 was issued on August 12, 2008. Its term was governed by the 20-year patent-term rule measured from the earliest effective nonprovisional or PCT filing date, subject to patent-term adjustment and any applicable extensions.[1]

The patent’s nominal term ended in the 2023-2024 period, based on its priority and filing chain. It is no longer a live long-term exclusivity asset for new commercial launches. Any enforceability analysis must distinguish:

The original patent term.
Patent-term adjustment.
Patent-term extension.
Terminal disclaimers.
Maintenance-fee status.
Any disclaimer or recorded lapse.
Accrued damages before expiration.

The patent does not appear to provide a current blocking right against a new U.S. product based solely on the original claims. Its historical value was greater during the development and launch period for ingenane-based oncology and dermatology products.

How many patents cover the same commercial territory?

The relevant landscape has several layers:

Layer	Typical protected subject matter	Relevance to 7,410,656
Active compound	Ingenol mebutate or related ingenanes	Overlaps only if the structural definition reaches the accused compound
Method of treatment	Cancer, actinic keratosis, proliferative disorders	Directly overlaps the supplied claims
Formulation	Gel, cream, vehicle, concentration, stability	Not expressly claimed in the supplied claims
Manufacturing	Extraction, purification, esterification, crystallization	Outside the supplied claim set
Combination therapy	Use with chemotherapy, radiation, immune therapy, or other agents	Potentially separate protection
Biomarker or patient selection	Defined patient populations or treatment response	Separate method-of-use territory
Regulatory exclusivity	FDA new-drug, orphan, or pediatric exclusivity	Independent of patent term

The core competitive risk therefore cannot be assessed from Patent 7,410,656 alone. A generic or follow-on developer would need to screen compound, formulation, process, method-of-use, and regulatory records.

What patent landscape surrounds ingenol mebutate?

Ingenol mebutate was developed by Peplin Pty Ltd and later commercialized through LEO Pharma. The product’s relevant intellectual-property estate included patent families covering:

Ingenol derivatives.
Therapeutic uses.
Topical compositions.
Treatment of actinic keratosis.
Production and purification of ingenol compounds.

The commercial product was not a biologic. Biosimilar rules under the Public Health Service Act therefore do not apply. Any follow-on product would proceed through a small-molecule drug pathway, potentially including an abbreviated new drug application if the reference-product and dosage-form requirements were satisfied.

Because Picato was withdrawn rather than replaced by an active U.S. reference-market product, the commercial pathway for a generic substitute is more complicated than a standard ANDA launch against a currently marketed reference product. Regulatory feasibility would depend on FDA treatment of the reference product, current listing status, and the proposed product’s safety and efficacy basis.

Were there Paragraph IV challenges or patent litigation?

The supplied patent was not the principal publicly recognized litigation battleground for Picato’s U.S. commercial history. The more important commercial disputes involving topical ingenol products concerned product rights, market access, safety, and the broader patent estate.

A Paragraph IV certification would have required a generic applicant to challenge listed patents associated with an FDA reference product. Patent 7,410,656 could only support an Orange Book-based Paragraph IV case if it was listed for the relevant approved product and indication. A patent that claims an unapproved compound or an unapproved cancer use would not automatically qualify for Orange Book listing.

The supplied claims do not establish that Patent 7,410,656 was listed in the Orange Book for Picato. Orange Book listing is product-specific and depends on FDA listing records, approved labeling, and the patent’s relationship to the approved drug substance, drug product, or method of use.[4]

What is the Orange Book status of U.S. Patent 7,410,656?

The patent should not be treated as an Orange Book barrier merely because it concerns an ingenane compound.

For Orange Book purposes, the relevant questions are:

Whether the patent was submitted for an approved NDA.
Whether it claims the active ingredient, drug product, or approved method of use.
Whether FDA accepted the listing.
Whether the approved labeling carried the corresponding use code.
Whether the patent remained listed when an ANDA was filed.

Picato’s approved indication was actinic keratosis. Claims directed to broader oncology uses or to 20-O-acetyl-ingenol-3-angelate would not necessarily correspond to that approved indication. A method-of-use patent may be listed only when its claimed use is reflected in the approved labeling.

How strong is the patent estate?

The patent had moderate historical scope but limited current blocking strength.

Strengths

Claim 1 uses a broad structural genus.
The claims cover both dermatologic disease and solid tumors.
Claim 3 identifies a specific compound with clear chemical definition.
The claims are method claims, allowing coverage of therapeutic use without requiring a particular formulation.
Claim 5 reaches actinic keratosis, a commercially relevant dermatologic indication.

Limitations

The patent does not claim the compound per se.
The patent does not claim a formulation, dosage, concentration, or manufacturing process.
Claim 1 may face structural and written-description disputes if applied to compounds not exemplified in the specification.
Claim 3 does not expressly cover ingenol mebutate.
The patent term has ended or reached the end of its enforceable period.
FDA withdrawal of Picato materially reduced the commercial value of the covered therapeutic area.
A competitor could pursue a structurally distinct ingenane, a different diterpene class, or an alternative treatment mechanism.

The most defensible historical asset was claim 3 against a product that actually used 20-O-acetyl-ingenol-3-angelate for a claimed cancer-related purpose. The broadest commercial relevance rested on claim 1, but that claim also presented the greatest claim-construction and validity exposure.

What generic launch risks exist?

A follow-on developer assessing an angeloyl-substituted ingenane would face five principal risks:

Structural overlap with claim 1 if the active ingredient is an angeloylated ingenane.
Method-of-use overlap for actinic keratosis or the listed cancers.
Separate formulation patents covering topical delivery.
Manufacturing patents covering purification or esterification.
FDA safety and clinical-development requirements following Picato’s withdrawal.

A product using ingenol mebutate would present a different risk profile from a product using 20-O-acetyl-ingenol-3-angelate. The former may implicate the broad genus claim but not claim 3. The latter directly implicates the species claim if used for the claimed therapeutic purposes, subject to the patent’s term and enforceability.

Key Takeaways

U.S. Patent 7,410,656 is a method-of-treatment patent, not a broad composition or manufacturing patent.
Claim 1 covers administering an isolated angeloyl-substituted ingenane to inhibit neoplastic-cell proliferation.
Claim 3 specifically covers 20-O-acetyl-ingenol-3-angelate.
Ingenol mebutate is structurally different and is not expressly named in claim 3.
Claims 5 and 6 cover dermatologic cancers, actinic keratosis, solid tumors, and specified cancers.
The patent does not expressly claim topical gels, dosage strengths, excipients, or administration schedules.
Picato was FDA-approved for actinic keratosis and withdrawn in 2020 because of skin-cancer concerns.
The patent’s original term ran out in the 2023-2024 period, eliminating its value as a current long-term blocking patent.
Biosimilar law is not relevant because these are small-molecule ingenane compounds.
A full freedom-to-operate analysis requires review of the broader compound, formulation, manufacturing, use, Orange Book, and regulatory records.

FAQs About U.S. Patent 7,410,656

Does Patent 7,410,656 claim ingenol mebutate itself?

No. The patent claims methods using angeloyl-substituted ingenanes and specifically names 20-O-acetyl-ingenol-3-angelate. Ingenol mebutate is ingenol 3-angelate and lacks the express C-20 acetyl group in claim 3.

Does the patent cover treatment of actinic keratosis?

Yes. Claim 5 expressly includes solar keratosis, the historical terminology for actinic keratosis.

Is Patent 7,410,656 still enforceable against a new generic?

The patent’s 20-year term ended in the 2023-2024 period. It should not be treated as a current primary barrier to launch, although pre-expiration conduct and any recorded term adjustments would require separate legal analysis.

Does the patent cover an ingenane manufacturing process?

No. The supplied claims do not recite extraction, purification, synthesis, esterification, crystallization, or any other manufacturing step.

Are biosimilar applicants relevant to this patent?

No. Ingenane products are small-molecule drugs. Follow-on applicants would use small-molecule regulatory pathways rather than the biosimilar pathway.

References

United States Patent and Trademark Office. (2008). U.S. Patent No. 7,410,656: Use of ingenane derivatives for treating neoplastic diseases.
U.S. Food and Drug Administration. (2012). FDA approves drug for actinic keratosis.
U.S. Food and Drug Administration. (2020). FDA confirms increased risk of skin cancer with Picato (ingenol mebutate) gel.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. Orange Book.
LEO Pharma A/S. (2012). Picato (ingenol mebutate) gel prescribing information.

Foriegn Application Priority Data
Foreign Country	Foreign Patent Number	Foreign Patent Date
Australia	PO 8640	Aug 19, 1997

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
European Patent Office	1015413	⤷ Start Trial	C300592	Netherlands	⤷ Start Trial
European Patent Office	1015413	⤷ Start Trial	CA 2013 00024	Denmark	⤷ Start Trial
European Patent Office	1015413	⤷ Start Trial	92185	Luxembourg	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,410,656

Summary for Patent: 7,410,656