US Patent 9,226,931: Scope, Claims, Expiration Risk, and Bimatoprost Patent Landscape

US Patent No. 9,226,931 covers the use of bimatoprost to prevent or treat chemotherapy-associated hair loss, with its strongest protection directed to eyelash preservation and regrowth. The patent is a method-of-treatment patent, not a composition patent. Its core claims do not require a particular concentration, dosage form, frequency, or treatment duration. Those limitations appear in dependent claims.

The principal commercial risk is an indication-specific use restriction. A generic bimatoprost product could potentially enter for an approved ophthalmic indication while creating patent exposure if its labeling, promotion, distribution, or clinical use supports chemotherapy-related eyelash treatment. The patent does not create biosimilar risk because bimatoprost is a small-molecule active ingredient.

What does US Patent 9,226,931 cover?

The patent covers applying bimatoprost to selected hair-bearing sites in patients receiving chemotherapy or recovering from chemotherapy.

Claim group	Covered subject matter	Key limitations
Claims 1-11	Increasing hair growth in chemotherapy patients	Bimatoprost applied to the eyelids, eyebrows, or scalp before, during, or after chemotherapy
Claims 12-20	Preventing eyelash loss during chemotherapy	Bimatoprost applied to the eyelids before, during, or after chemotherapy
Claims 2-9	Specific eyelash-growth regimen	0.03% bimatoprost, once or twice daily, with treatment extending six or 12 months after chemotherapy
Claims 11	Combination treatment	Bimatoprost administered with minoxidil or Propecia
Claim 19	Dosage form	Bimatoprost in a solution or emulsion
Claim 20	Application site	Upper eyelid, lower eyelid, or both

The two independent claims define the commercial center of gravity:

Claim 1 addresses increasing hair growth.
Claim 12 addresses preventing eyelash loss.

The claims cover treatment before, during, and after chemotherapy. The temporal language is broad and does not limit protection to a particular chemotherapy agent, cancer type, dosing regimen, or chemotherapy cycle.

How broad is claim 1 of US 9,226,931?

Claim 1 is broad in treatment timing, patient population, and application site. It requires:

A chemotherapy patient.
A method of increasing hair growth.
Application of bimatoprost.
Application to the eyelids, eyebrows, or scalp.
Application before, during, or after chemotherapeutic treatment.

The claim does not require 0.03% bimatoprost. It does not require once-daily or twice-daily dosing. It does not require a solution, emulsion, applicator, or particular treatment duration.

The claim therefore reaches a range of regimens beyond the Latisse-style once-daily 0.03% upper-eyelid regimen. A product or clinical protocol using a different bimatoprost concentration could still fall within claim 1 if it is used to increase hair growth in a chemotherapy patient at one of the specified sites.

The principal limiting element is the intended treatment result: increasing hair growth. A purely cosmetic use unrelated to chemotherapy would not satisfy the chemotherapy-patient limitation, although intent and labeling would be evaluated from the totality of the facts.

How broad is claim 12 on preventing eyelash loss?

Claim 12 is the second independent claim and may be more commercially significant than claim 1. It covers applying bimatoprost to the eyelids of a patient undergoing chemotherapy to prevent loss of eyelashes.

Unlike claim 1, claim 12 is directed specifically to prevention. It does not require that the patient already have hair loss. It also does not require a particular concentration, dosage frequency, formulation, or eyelid location.

The claim reaches application:

Before chemotherapy;
During chemotherapy; or
After chemotherapy.

Claims 17 and 18 narrow this protection by specifying use before chemotherapy, including a three-month pretreatment period. Claims 14-16 add the result of less eyelash loss compared with untreated post-chemotherapy patients and treatment for at least six or 12 months after chemotherapy.

What formulations and dosing regimens are protected?

The patent does not broadly claim a new bimatoprost molecule or a new ophthalmic formulation. Claim 19 expressly covers bimatoprost in solution or emulsion form, but that claim remains tied to prevention of eyelash loss in chemotherapy patients.

The most commercially relevant dependent regimen is:

0.03% w/v bimatoprost;
Applied at least once daily;
Applied to the eyelids;
Used for at least six months, and in a narrower claim, at least 12 months after chemotherapy.

Claim 8 covers twice-daily use. Claim 9 specifies application to the upper and lower eyelid margins of each eye.

The claims do not require the branded Latisse applicator, a single-use brush, a preservative system, a particular pH, or a specific package configuration. A solution or emulsion containing bimatoprost could satisfy claim 19 if the chemotherapy-related use limitations are met.

What is the relationship to Latisse and generic bimatoprost?

Latisse contains bimatoprost 0.03% and is FDA-approved for hypotrichosis of the eyelashes. Its approved labeling generally directs once-daily application to the upper eyelid margins. It does not establish an FDA-approved chemotherapy-related indication. [2]

Product or use	Active ingredient	FDA status	Relevance to US 9,226,931
Latisse	Bimatoprost 0.03%	Approved for eyelash hypotrichosis	Label does not establish chemotherapy use
Lumigan	Bimatoprost ophthalmic solution	Approved for reduction of elevated intraocular pressure	Ophthalmic formulation and ingredient overlap
Generic bimatoprost ophthalmic solution	Bimatoprost	Approved through abbreviated or related pathways for ophthalmic indications	Potential off-label use and induced-use issues
Proposed chemotherapy indication	Bimatoprost	No approval established by the patent claims	Direct subject matter of US 9,226,931

The patent does not prevent all sales of bimatoprost. It targets a specific use in chemotherapy patients. That distinction is important for generic entry analysis. A generic applicant may seek approval for a non-chemotherapy indication while omitting the patented use from labeling, subject to the scope of the applicable regulatory pathway and the patent certifications required for listed patents.

When does US Patent 9,226,931 lose exclusivity?

The patent issued on January 5, 2016. Its enforceable term is generally calculated as 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, terminal disclaimers, and any other term modifications recorded by the USPTO. The patent’s expiration cannot be established from the claim text alone.

For commercial diligence, the operative date is the expiration date shown in the USPTO patent record after accounting for:

Patent-term adjustment;
Any terminal disclaimer;
Continuation or divisional relationships;
Patent-term extension, if applicable;
Reexamination or post-grant changes.

A chemotherapy-use patent normally does not receive Hatch-Waxman patent-term extension merely because the underlying product has FDA approval. Patent-term extension under 35 U.S.C. § 156 is tied to regulatory review of the patented product or method and requires satisfaction of statutory conditions. [3]

The patent’s practical exclusivity may end earlier than its statutory expiration if the claims are invalidated, narrowed, disclaimed, or rendered commercially irrelevant by a label design that avoids the claimed use.

Is US 9,226,931 listed in the Orange Book?

The Orange Book lists patents submitted for approved drug products and used in the Hatch-Waxman patent-certification framework. A use patent is not automatically listed merely because it covers a potential use of an active ingredient.

The relevant questions are:

Whether US 9,226,931 was submitted to FDA for an approved bimatoprost product;
Whether FDA accepted the submission for Orange Book listing;
Whether the listed patent claims an approved method of use;
Whether the approved labeling includes the chemotherapy-related use.

The patent claims a chemotherapy-related use that is distinct from the approved Latisse eyelash-hypotrichosis indication. Unless FDA accepted the patent for listing against an approved product and approved use, it would not necessarily create a conventional Orange Book Paragraph IV barrier.

FDA’s Orange Book database is the controlling source for current listing status. [1]

What Paragraph IV challenges are possible?

A Paragraph IV certification is relevant only when a generic applicant references an NDA with a listed patent. The applicant asserts that the patent is invalid, unenforceable, or will not be infringed by the proposed product.

Potential Paragraph IV theories against US 9,226,931 include:

Noninfringement

A generic applicant could omit the chemotherapy-related use from its proposed labeling. The resulting case would turn on whether the labeling nevertheless encourages or makes the patented use reasonably foreseeable.

A label limited to glaucoma or non-chemotherapy eyelash hypotrichosis would present a stronger noninfringement position than a label mentioning chemotherapy-associated eyelash loss, cancer patients, or prevention of chemotherapy-induced alopecia.

Anticipation and obviousness

Bimatoprost was known to affect eyelash growth before the patent. The relevant validity question is whether prior art disclosed or made obvious the use of bimatoprost for preventing or treating chemotherapy-associated hair loss.

Potential prior-art categories include:

Earlier bimatoprost eyelash-growth studies;
Prostaglandin analog treatment of hair growth;
Chemotherapy-induced alopecia treatments;
Clinical or patent disclosures combining chemotherapy with hair-growth agents;
Use of minoxidil or finasteride in chemotherapy-related hair loss.

The chemotherapy-specific patient population and prevention objective provide the principal distinction from ordinary eyelash-growth prior art. The strength of that distinction depends on the patent’s prosecution history and the evidence available before its priority date.

Written description and enablement

The claims cover eyelids, eyebrows, and scalp, as well as treatment before, during, and after chemotherapy. A validity challenge could argue that the specification did not adequately support the full breadth of these combinations, particularly scalp or eyebrow treatment, prevention before chemotherapy, or extended treatment for 12 months.

The claims also use comparative and functional language, including "increasing hair growth," "less eyelash loss," and "effectively treats post-chemotherapeutic hair loss." Those terms may be construed in light of the specification and may create factual disputes over the required clinical result.

Indefiniteness

The phrase "before, during, or after chemotherapeutic treatment" is broad but generally understandable. Greater risk may attach to result language such as "effectively treats" if the specification does not provide an objective boundary for that term.

How strong is the patent estate?

The estate appears strongest against a product or service that expressly promotes bimatoprost for chemotherapy-related eyelash preservation or regrowth. The strongest claim features are:

Explicit chemotherapy-patient limitation;
Express prevention and treatment theories;
Coverage before, during, and after chemotherapy;
No requirement for a particular chemotherapy drug;
Dependent claims aligned with the established 0.03% bimatoprost eyelash regimen.

The estate is weaker against:

A generic product labeled only for intraocular pressure reduction;
A product labeled only for ordinary eyelash hypotrichosis;
Use outside chemotherapy patients;
A formulation that does not contain bimatoprost;
A treatment protocol using a different active ingredient;
Clinical use that lacks evidence of intent to prevent or treat chemotherapy-associated hair loss.

Because the patent is a single US method patent based on the supplied claims, it does not create a broad composition, formulation, manufacturing, or device monopoly.

What patent litigation and settlements affect the patent?

The patent document itself does not establish litigation, settlement, licensing, or Paragraph IV activity. No litigation outcome can be attributed to US 9,226,931 without a docket-specific review of district court, Federal Circuit, USPTO, and FDA records.

A complete freedom-to-operate review should distinguish this patent from:

Earlier bimatoprost composition patents;
Latisse formulation or delivery patents;
Ophthalmic formulation patents;
Manufacturing-process patents;
Patents covering prostaglandin analogs for hair growth;
Foreign counterparts and national-phase applications.

A settlement involving a different bimatoprost patent would not automatically resolve the claims of US 9,226,931.

What generic launch scenarios exist?

Launch scenario	Patent exposure
Generic bimatoprost labeled only for glaucoma-related use	Lower direct exposure to the chemotherapy method claims
Generic labeled for ordinary eyelash hypotrichosis	Potential exposure if chemotherapy use is included or encouraged
Product with chemotherapy-related eyelash language	High risk under claims 1 and 12
Physician-directed off-label chemotherapy use without manufacturer promotion	Case-specific inducement and contributory-infringement risk
New formulation without bimatoprost	Outside the literal claims
Bimatoprost for scalp hair loss in chemotherapy patients	Potential claim 1 exposure
Bimatoprost used before chemotherapy for three months	Directly aligned with claims 17 and 18

FDA approval and patent freedom are separate questions. Approval of a generic bimatoprost product does not eliminate infringement risk under a valid method-of-use claim.

Does the patent create biosimilar risk?

No. Bimatoprost is a chemically synthesized small molecule. The relevant competitors are generic drug manufacturers, branded ophthalmic companies, specialty pharmacies, and potential oncology-supportive-care developers. The FDA Purple Book biosimilar framework does not govern ordinary bimatoprost products. [4]

What geographic coverage does the patent provide?

US 9,226,931 provides rights in the United States only. Patent protection in Europe, Canada, Japan, or other markets requires separate granted national patents. A PCT application, if one exists, does not itself create enforceable rights in every country.

Foreign commercial diligence should separately evaluate:

National-phase filings;
Granted claims;
Local patent-term rules;
Supplementary protection certificates;
Opposition or revocation proceedings;
Local use and indirect-infringement standards.

Key Takeaways

US 9,226,931 is a chemotherapy-specific bimatoprost method-of-use patent.
Claims 1 and 12 are the principal independent claims.
The patent covers prevention and treatment, not only post-treatment regrowth.
The claims reach eyelids, eyebrows, and, under claim 1, the scalp.
The broad independent claims do not require 0.03% bimatoprost or a specific formulation.
Dependent claims specifically cover once-daily and twice-daily eyelid use, solution or emulsion formulations, and six- or 12-month post-chemotherapy treatment.
Latisse’s FDA approval for eyelash hypotrichosis does not establish approval for chemotherapy-associated hair loss.
Generic bimatoprost entry may be possible with a non-chemotherapy label, but promotion or labeling directed to chemotherapy patients creates greater infringement risk.
No biosimilar pathway applies.
Orange Book status must be confirmed from FDA’s current listing for the relevant bimatoprost NDA.
The patent’s statutory expiration depends on the earliest effective nonprovisional filing date and USPTO term adjustments.

FAQs

Can bimatoprost be used for chemotherapy hair loss without infringing US 9,226,931?

The risk depends on the product, prescriber conduct, promotion, and facts showing intent to practice the claimed method. Use directed to chemotherapy-associated eyelash prevention or regrowth maps closely to claims 1 and 12.

Does claim 1 cover scalp hair regrowth after chemotherapy?

Yes. Claim 1 expressly includes the scalp. The claim requires bimatoprost application to a chemotherapy patient for increasing hair growth.

Does the patent cover latanoprost or travoprost?

No. The supplied claims require bimatoprost. Other prostaglandin analogs are outside the literal scope, although separate patents could apply.

Is twice-daily treatment required for infringement?

No. Twice-daily application appears in dependent claim 8. The independent claims do not require a particular dosing frequency.

Does claim 19 cover every bimatoprost solution?

No. Claim 19 remains limited to the chemotherapy-related eyelash-loss prevention method of claim 12. It does not claim every bimatoprost solution regardless of use.

References

U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2008). Latisse (bimatoprost ophthalmic solution) 0.03% prescribing information. Allergan, Inc.
United States Code. 35 U.S.C. §§ 154, 156, and 271.
U.S. Food and Drug Administration. (n.d.). Purple Book: Lists of licensed biological products with reference product exclusivity and biosimilarity or interchangeability evaluations.
United States Patent and Trademark Office. (2016). U.S. Patent No. 9,226,931: Methods of treating hair loss associated with chemotherapy.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2003207843	⤷ Start Trial
Australia	2008203212	⤷ Start Trial
Australia	2010227111	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,226,931

Summary for Patent: 9,226,931