Details for Patent: 9,901,539

Which drugs does patent 9,901,539 protect, and when does it expire?

Patent 9,901,539 protects BELBUCA and is included in one NDA.

This patent has thirty-two patent family members in seventeen countries.

Summary for Patent: 9,901,539

Title:	Transmucosal drug delivery devices for use in chronic pain relief
Abstract:	Provided herein are methods for treating chronic pain by administering low doses of buprenorphine twice daily (or once daily) via a transmucosal drug delivery device. The methods and devices efficiently treat chronic pain without significant side effects.
Inventor(s):	Andrew Finn, Niraj Vasisht
Assignee:	Bpcr LP , Biodelivery Sciences International Inc
Application Number:	US13/724,959
Patent Litigation and PTAB cases:	See patent lawsuits and PTAB cases for patent 9,901,539
Patent Claim Types: see list of patent claims	Use; Delivery; Device;

U.S. Patent 9,901,539: Buprenorphine Buccal Film Claims, Scope, Expiration and Patent Landscape

U.S. Patent No. 9,901,539 protects clinical use of a buffered, mucoadhesive, bioerodable buprenorphine delivery device for opioid-experienced patients with chronic pain. The broadest claim combines device structure, dosing frequency, pharmacokinetic exposure, patient population and opioid adverse-event outcomes. The patent is directed primarily to the Belbuca buprenorphine buccal-film platform marketed by BioDelivery Sciences International, now part of Collegium Pharmaceutical.

The strongest infringement risk concerns an oral buprenorphine film that has the claimed pH profile, lacks an opioid antagonist in its backing layer, is administered once or twice daily to opioid-experienced patients, and produces the claimed plasma-exposure parameters. A generic or competing product may avoid literal infringement by using a different dosage form, a different buffer system, a different backing layer, or a different dosing and pharmacokinetic profile.

What does U.S. Patent 9,901,539 cover?

Patent 9,901,539 covers methods of treating chronic pain with a mucoadhesive bioerodable buprenorphine device applied to an oral mucosal surface. The claimed device is not defined merely by the presence of buprenorphine. It must satisfy multiple structural and clinical limitations.

Core claim elements

Claim element	Requirement
Active ingredient	Buprenorphine
Dosage form	Mucoadhesive, bioerodable drug-delivery device
Administration	Once or twice daily under claim 1; twice daily under claim 9
Route	Oral mucosal administration
Mucoadhesive layer	Buffered, bioerodable layer containing approximately 100 micrograms to 0.9 mg buprenorphine
Mucoadhesive-layer pH	Approximately 4.0 to 6.0
Backing layer	Buffered to approximately pH 4.0 to 4.8
Backing-layer composition	No opioid antagonist
Patient population	Opioid-experienced subject
Indication	Chronic pain, including chronic low back pain, neuropathic pain and osteoarthritic pain
Pharmacokinetics	Claim 1 requires steady-state Cmax of approximately 0.156 to 0.364 ng/mL
Clinical outcome	Mild or moderate common opioid adverse effects, or no common opioid adverse effects

The claims are method-of-treatment claims. They do not broadly claim every buprenorphine buccal film or every buprenorphine formulation. Infringement generally requires performance of the claimed treatment method, either directly by a healthcare provider or patient, or indirectly through a product and labeling that encourages the claimed use.

How broad is the independent claim 1?

Claim 1 is technically broad in its indication language but narrow in its combined limitations. It covers “chronic pain” without restricting the disease to low back pain, neuropathic pain or osteoarthritis. The claim does, however, require all of the following:

1. A mucoadhesive bioerodable device.
2. A buprenorphine-containing mucoadhesive layer.
3. A specified acidic pH range for that layer.
4. A backing layer with a narrower acidic pH range.
5. No opioid antagonist in the backing layer.
6. Once- or twice-daily administration.
7. An opioid-experienced patient.
8. A specified steady-state Cmax range.
9. Mild or moderate opioid adverse effects, or none.

The pharmacokinetic limitation is important. A product may have the same active ingredient and a similar film but fall outside claim 1 if its steady-state Cmax is below or above the claimed range. That limitation also creates proof issues because infringement may depend on clinical or pharmacokinetic data rather than solely on product testing.

The supplied claim text uses “about 100 g” and similar expressions. In the buprenorphine context, these quantities are understood as microgram quantities, not grams. A gram-level buprenorphine dose would be commercially and clinically inconsistent with the claimed product class.

What do dependent claims 2 through 22 add?

The dependent claims create narrower positions around dosing, indications, pharmacokinetics and adverse-event rates.

Indication and dosing claims

Claims 2 through 7 and 10 through 13 narrow the treatment method as follows:

• Claim 2 requires once-daily administration.
• Claim 3 covers chronic low back pain.
• Claim 4 covers moderate to severe chronic low back pain.
• Claims 5 and 6 require treatment without significant constipation or nausea.
• Claim 7 lists specific total daily doses from 200 micrograms to 1,800 micrograms.
• Claim 10 covers neuropathic pain.
• Claim 11 covers osteoarthritic pain.
• Claim 12 lists individual device strengths from 100 micrograms to 180 micrograms.
• Claim 13 covers a total daily dose from 200 micrograms to approximately 1,800 micrograms.

Claim 9 is a separate independent claim. It requires twice-daily administration for moderate to severe chronic low back pain and requires the buprenorphine to be disposed in a buffered polymeric diffusion environment. Claim 9 does not recite the specific Cmax limitation appearing in claim 1, but it retains the patient, backing-layer, pH and adverse-effect limitations.

Pharmacokinetic claims

Claim	Pharmacokinetic limitation
1	Steady-state Cmax of approximately 0.156 to 0.364 ng/mL
14	Steady-state Tmax of approximately 2.00 to 2.90 hours
15	Cmin of approximately 0.0157 to 0.0862 ng/mL
16	Steady-state AUClast of approximately 0.4085 to 5.033 h·ng/mL

These claims may be valuable against a product that uses a similar film but attempts to distinguish itself through dose strength or labeling. The ranges are vulnerable to disputes over assay methodology, fed or fasting conditions, patient population, steady-state definition and statistical treatment of pharmacokinetic results.

Adverse-event claims

Claims 17 through 22 recite ranges for treatment-emergent adverse events:

Claim	Event rate
17	Headache: approximately 2.4% to 6.9%
18	Dizziness: approximately 3.0% to 6.9%
19	Nausea: approximately 2.6% to 27.9%
20	Constipation: approximately 1.5% to 8.5%
21	Vomiting: approximately 0.9% to 3.0%
22	Total mild or moderate treatment-emergent adverse events: approximately 7.7% to 33.9%

These limitations are narrower and more difficult to use in a product case because they require population-level clinical evidence. A product label alone may not establish that the claimed event range is met. Conversely, clinical-trial data, regulatory submissions or comparative pharmacology reports could support infringement if the relevant population and treatment conditions correspond to the claims.

What formulation features are protected by Patent 9,901,539?

The patent protects a specific multilayer buccal-film architecture when used in the claimed treatment method.

Mucoadhesive layer

The mucoadhesive layer must be bioerodable and contain buprenorphine in a buffered environment with a pH of approximately 4.0 to 6.0. This limitation links formulation chemistry to mucosal delivery and drug release.

The claims do not require a particular polymer by name in claim 1. A competing product therefore may infringe even if it uses a different mucoadhesive polymer, provided the resulting device meets the structural and functional limitations.

Backing layer

The backing layer must be buffered to approximately pH 4.0 to 4.8 and cannot include an opioid antagonist. This limitation distinguishes the claimed delivery device from combination products containing naloxone or another antagonist.

A product with naloxone in a separate layer, backing layer or integrated formulation could create a noninfringement position, although the precise location and function of the antagonist would matter. A formulation that omits an antagonist but uses a different backing-layer pH may also avoid literal infringement.

Barrier and diffusion layer

Claim 8 adds a polymeric barrier environment adjacent to the mucoadhesive layer. The layer creates a unidirectional gradient intended to move buprenorphine across the buffered polymeric diffusion environment and into the mucosal surface.

This limitation is directed to controlled directionality of delivery. A competing film that produces substantial bidirectional diffusion, uses a different barrier arrangement, or does not contain the claimed adjacent polymeric environment may have a stronger noninfringement position.

What product is most closely associated with Patent 9,901,539?

The claimed technology corresponds closely to Belbuca, a buprenorphine buccal film approved by the U.S. Food and Drug Administration for the management of pain severe enough to require a daily, around-the-clock, long-term opioid analgesic when alternative treatment options are inadequate.

Belbuca is available in multiple microgram strengths and is applied to the buccal mucosa. Its approved labeling identifies buprenorphine as the active ingredient and describes opioid-experienced and opioid-naive dosing considerations. The product does not use naloxone in its commercial buccal film formulation [2].

Commercial product	Active ingredient	Dosage form	Primary U.S. sponsor
Belbuca	Buprenorphine	Buccal film	BioDelivery Sciences International, now associated with Collegium Pharmaceutical
Butrans	Buprenorphine	Transdermal system	Organon and predecessor companies
Subutex	Buprenorphine	Sublingual tablet	Various authorized and generic sponsors
Suboxone	Buprenorphine/naloxone	Sublingual film or tablet	Indivior
Generic buprenorphine products	Buprenorphine, with or without naloxone depending on product	Sublingual tablet, film or other dosage forms	Multiple sponsors

Butrans, Subutex and Suboxone are not automatically within the claims because the patent requires a mucoadhesive bioerodable oral device with the claimed pH and backing-layer characteristics. Transdermal and sublingual dosage forms generally present materially different structures.

What is the patent expiration date for U.S. Patent 9,901,539?

U.S. Patent 9,901,539 issued on February 27, 2018. Its term is generally tied to the earliest effective nonprovisional filing date in the relevant patent family and may be affected by patent-term adjustment, terminal disclaimers, patent-term extension and any Orange Book listing.

The patent is associated with the Belbuca patent estate, which has been reported as extending into the late 2020s. A working commercial assumption is that the relevant patent protection runs to approximately June 2027, subject to the official USPTO term calculation and any applicable adjustment. The precise enforceable expiration date should be determined from the USPTO patent-term data and current Orange Book listing rather than from the issue date alone [1, 3].

Exclusivity timeline

Event	Date or period
FDA approval of Belbuca	2015
U.S. Patent 9,901,539 issued	February 27, 2018
Expected core patent-estate horizon	Approximately 2027, subject to official term calculation
Generic entry before expiry	Requires invalidity, noninfringement, settlement or other legal pathway
Regulatory exclusivity	Separate from patent term and generally does not control the full commercial exclusivity period

FDA regulatory exclusivity and patent protection are separate. A product may lose New Drug Application exclusivity while remaining protected by Orange Book-listed patents. Conversely, expiration of a patent does not eliminate any remaining regulatory exclusivity.

What is the Orange Book status of Patent 9,901,539?

Patent 9,901,539 is associated with the Belbuca patent estate and should be evaluated with the Orange Book entries for buprenorphine buccal film. Orange Book listings can change through patent delisting, corrections, pediatric exclusivity, litigation certifications and FDA administrative updates.

A complete Orange Book analysis should distinguish:

• Patents listed against the Belbuca NDA.
• Whether the patent claims the drug substance, drug product, formulation or method of use.
• The use code submitted for each method-of-use patent.
• Whether a generic applicant filed a Paragraph IV certification.
• Whether the NDA holder initiated litigation within the statutory 45-day period.
• Whether a 30-month stay was triggered.
• Whether any settlement permits an earlier launch.

The patent’s method-of-treatment character makes its use code and approved-label overlap central to any Paragraph IV dispute. A generic applicant may argue that its label does not encourage the patented chronic-pain use, or that the product does not satisfy the buccal-film and pharmacokinetic limitations.

Which companies are challenging the Belbuca patent estate?

The relevant competitive group includes generic manufacturers developing buprenorphine oral films, sublingual products or alternative opioid formulations. A company developing a non-buccal dosage form would face a different infringement analysis from a company seeking an AB-rated generic equivalent to Belbuca.

Known market participants in buprenorphine products include:

• Indivior, particularly in buprenorphine/naloxone products.
• Hikma Pharmaceuticals.
• Sandoz and other generic manufacturers.
• Organon and predecessor companies in transdermal buprenorphine.
• Collegium Pharmaceutical, through its ownership of the Belbuca commercial business.

A confirmed list of Paragraph IV challengers, filing dates, district court actions and settlement terms requires review of current Orange Book certifications, court dockets and FDA paragraph IV notification records. Patent 9,901,539 should not be treated as challenged merely because generic buprenorphine products exist. A generic sublingual tablet or buprenorphine/naloxone film is not necessarily a Paragraph IV challenge to the Belbuca claims.

What litigation risks affect a generic buprenorphine buccal film?

A generic buccal-film developer faces four principal risk categories.

Literal infringement

Literal infringement risk is highest where the proposed product:

• Uses a bioerodable mucoadhesive buccal film.
• Contains buprenorphine at Belbuca-like strengths.
• Uses an acidic buffer in the 4.0 to 6.0 range.
• Uses a backing layer buffered near pH 4.0 to 4.8.
• Omits naloxone or another opioid antagonist.
• Is labeled for chronic pain in opioid-experienced patients.
• Is administered once or twice daily.

Induced infringement

A product label that recommends the patented use may support an induced-infringement theory. Label language concerning chronic low back pain, opioid-experienced patients, daily or twice-daily administration and long-term opioid treatment would be particularly relevant.

Doctrine of equivalents

A small change in pH, polymer composition or barrier-layer arrangement may not eliminate risk if the accused element performs substantially the same function in substantially the same way to obtain substantially the same result. The no-opioid-antagonist limitation may be more difficult to address through equivalence because it is an express compositional limitation.

Validity challenges

Potential validity issues include:

• Written-description support for broad chronic-pain and adverse-event ranges.
• Enablement of the full dose and pharmacokinetic ranges.
• Obviousness based on prior buprenorphine buccal films, opioid pharmacokinetics and chronic-pain clinical protocols.
• Indefiniteness of terms such as “opioid-experienced,” “common opioid adverse effects,” “significant constipation” and “about.”
• Whether the clinical outcome limitations impose sufficiently definite claim boundaries.
• Whether the pharmacokinetic ranges are inherent properties of a known formulation or an unexpected result.

The strongest validity attack would likely combine prior buprenorphine mucosal delivery technology with clinical evidence showing predictable treatment of chronic pain. The patent owner would respond that the claimed pH, multilayer construction, exposure profile and tolerability results produce a non-obvious clinical combination.

How strong is the patent estate for Belbuca?

The patent estate is strongest against a product that is structurally and clinically close to Belbuca. It is weaker against products that use a different route, a different dosage form or a different active-ingredient combination.

Competing product type	Risk under Patent 9,901,539	Principal reason
Direct generic buprenorphine buccal film	High	Likely overlap in structure, route and indication
Different buprenorphine buccal polymer system	Moderate to high	Depends on pH, backing layer and pharmacokinetics
Buprenorphine sublingual tablet	Low to moderate	Different dosage form and mucosal delivery architecture
Buprenorphine/naloxone film	Low to moderate	Opioid-antagonist limitation may support noninfringement
Transdermal buprenorphine	Low	Different route and device
Abuse-deterrent buprenorphine formulation	Variable	Depends on buccal-film structure and chronic-pain labeling
Compounded oral mucosal product	Fact-specific	May raise direct or induced-infringement issues

The estate’s commercial value depends more on the claims covering an FDA-substitutable buccal film than on the broad chronic-pain language alone. A generic applicant seeking an AB rating for Belbuca would face greater exposure than a sponsor launching a non-substitutable buprenorphine product for opioid-use disorder.

What generic launch scenarios exist?

Three launch scenarios are commercially plausible.

Launch after ordinary patent expiry

This is the lowest-risk pathway. The generic sponsor waits until the relevant Orange Book patents expire and any regulatory exclusivity ends. Market entry would then depend on FDA approval and any remaining nonlisted patent rights.

Paragraph IV launch

A generic sponsor may certify that the listed patent is invalid, unenforceable or not infringed. The NDA holder may sue within 45 days, potentially triggering a 30-month stay of approval under the Hatch-Waxman framework [4].

A Paragraph IV case would likely focus on claim construction of the pH ranges, “opioid-experienced” status, backing-layer composition, pharmacokinetic limitations and whether the generic label induces the claimed chronic-pain use.

At-risk launch

A generic may launch before final resolution of the patent dispute. That approach creates potential damages, injunctive relief and commercial disruption. It is more attractive where the challenger has a strong noninfringement position or where the remaining patent term is short relative to litigation duration.

Are biosimilar risks relevant to Patent 9,901,539?

No. Buprenorphine is a small-molecule active pharmaceutical ingredient, not a biologic. Biosimilar approval under the Public Health Service Act is not the relevant pathway. Generic competition would proceed primarily under the Abbreviated New Drug Application framework, with patent certifications governed by Hatch-Waxman procedures.

What licensing and ownership issues affect the patent?

The technology originated with BioDelivery Sciences International and its buccal-film platform. Collegium Pharmaceutical acquired BioDelivery Sciences and its commercial and development assets, including Belbuca. Ownership, assignment and enforcement authority should be checked in the USPTO assignment database and the patent’s current ownership records.

Licensing analysis should distinguish:

• Ownership of Patent 9,901,539.
• Rights to the underlying BEMA or buccal-film delivery technology.
• Rights to clinical data and the Belbuca NDA.
• Manufacturing licenses for film production.
• Any settlement or supply agreement involving a generic challenger.
• Rights outside the United States.

A technology license covering the film platform does not necessarily grant rights to the chronic-pain method claims, and a product commercialization agreement does not necessarily transfer patent enforcement authority.

What manufacturing and geographic barriers remain?

The key manufacturing barrier is reproducible multilayer-film production with controlled drug loading, adhesive behavior, dissolution, pH and backing-layer performance. A competitor must also demonstrate consistent pharmacokinetics across strengths and manufacturing lots.

Geographic protection is separate by jurisdiction. U.S. Patent 9,901,539 has no direct effect in Canada, Europe, Japan or other markets. Foreign counterparts require separate validity, term and enforcement analysis. Regulatory approval of an equivalent buprenorphine film in another country does not establish freedom to operate in the United States.

Key Takeaways

• U.S. Patent 9,901,539 is a method-of-treatment patent centered on buffered buprenorphine buccal films.
• The broadest claim requires both formulation structure and clinical-use conditions.
• The principal protected features are the acidic mucoadhesive layer, acidic antagonist-free backing layer, oral mucosal administration, opioid-experienced population and specified pharmacokinetic exposure.
• Claims 9 and 13 are commercially important because they cover moderate to severe chronic low back pain and daily dose ranges relevant to Belbuca.
• The adverse-event and pharmacokinetic claims create narrower fallback positions but may be difficult to enforce without patient-level or clinical-trial evidence.
• The patent is associated with the Belbuca patent estate, which has a late-2020s commercial protection horizon, commonly estimated around 2027 subject to official term calculations.
• Generic sublingual, transdermal or buprenorphine/naloxone products do not automatically infringe.
• The highest litigation risk is a direct generic buprenorphine buccal film with Belbuca-like labeling, composition and pharmacokinetics.
• Biosimilar procedures are not relevant because buprenorphine is a small molecule.
• Orange Book listings, Paragraph IV certifications, litigation and settlements must be evaluated at the patent-family and NDA level.

FAQs About U.S. Patent 9,901,539

Does Patent 9,901,539 cover all buprenorphine products?

No. It is directed to specified mucoadhesive bioerodable oral delivery devices and methods of treating chronic pain. Transdermal systems, sublingual tablets and products containing naloxone may avoid one or more claim limitations.

Does a buprenorphine/naloxone film infringe this patent?

Not necessarily. The claims require a backing layer that does not include an opioid antagonist. A buprenorphine/naloxone product may therefore have a substantial literal noninfringement argument, depending on the location and function of naloxone.

Is chronic low back pain required by every independent claim?

No. Claim 1 covers chronic pain generally, while claim 9 specifically requires moderate to severe chronic low back pain. Dependent claims separately address low back pain, neuropathic pain and osteoarthritic pain.

Can a generic avoid infringement by changing the buprenorphine dose?

Possibly, but not automatically. Claims 7, 12 and 13 cover broad sets of individual and total daily doses. A dose change must be evaluated against every limitation, including pH, device structure, administration frequency and pharmacokinetic exposure.

Is FDA approval enough to establish freedom to operate?

No. FDA approval addresses regulatory requirements. It does not resolve patent infringement, validity, Orange Book disputes, induced infringement or the effect of a generic label on method-of-use claims.

References

1. United States Patent and Trademark Office. (2018). U.S. Patent No. 9,901,539, methods of treating pain using buprenorphine buccal film. U.S. Department of Commerce.

2. U.S. Food and Drug Administration. (2023). Belbuca prescribing information. FDA.

3. U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. FDA.

4. U.S. Food and Drug Administration. (2024). Hatch-Waxman amendments and abbreviated new drug applications. FDA.

Drugs Protected by US Patent 9,901,539

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Bdsi	BELBUCA	buprenorphine hydrochloride	FILM;BUCCAL	207932-001	Oct 23, 2015		RX	Yes	No	9,901,539					MANAGEMENT OF PAIN SEVERE ENOUGH TO REQUIRE DAILY, AROUND-THE-CLOCK, LONG-TERM OPIOID TREATMENT AND FOR WHICH ALTERNATIVE TREATMENT OPTIONS ARE INADEQUATE
Bdsi	BELBUCA	buprenorphine hydrochloride	FILM;BUCCAL	207932-002	Oct 23, 2015		RX	Yes	No	9,901,539					MANAGEMENT OF PAIN SEVERE ENOUGH TO REQUIRE DAILY, AROUND-THE-CLOCK, LONG-TERM OPIOID TREATMENT AND FOR WHICH ALTERNATIVE TREATMENT OPTIONS ARE INADEQUATE
Bdsi	BELBUCA	buprenorphine hydrochloride	FILM;BUCCAL	207932-003	Oct 23, 2015		RX	Yes	No	9,901,539					MANAGEMENT OF PAIN SEVERE ENOUGH TO REQUIRE DAILY, AROUND-THE-CLOCK, LONG-TERM OPIOID TREATMENT AND FOR WHICH ALTERNATIVE TREATMENT OPTIONS ARE INADEQUATE
Bdsi	BELBUCA	buprenorphine hydrochloride	FILM;BUCCAL	207932-004	Oct 23, 2015		RX	Yes	No	9,901,539					MANAGEMENT OF PAIN SEVERE ENOUGH TO REQUIRE DAILY, AROUND-THE-CLOCK, LONG-TERM OPIOID TREATMENT AND FOR WHICH ALTERNATIVE TREATMENT OPTIONS ARE INADEQUATE
Bdsi	BELBUCA	buprenorphine hydrochloride	FILM;BUCCAL	207932-005	Oct 23, 2015		RX	Yes	No	9,901,539					MANAGEMENT OF PAIN SEVERE ENOUGH TO REQUIRE DAILY, AROUND-THE-CLOCK, LONG-TERM OPIOID TREATMENT AND FOR WHICH ALTERNATIVE TREATMENT OPTIONS ARE INADEQUATE

International Family Members for US Patent 9,901,539

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2012358308
Australia	2017258916
Australia	2019202602
Australia	2021202042
Brazil	112014015329