United States Patent 7,696,236: Pirfenidone Dose-Escalation Claims, Exclusivity, and Patent Landscape

U.S. Patent No. 7,696,236 protects a specific method of administering pirfenidone for idiopathic pulmonary fibrosis (IPF). Its central limitation is the initial 14-day dose-escalation schedule: 801 mg/day during days 1-7, 1,602 mg/day during days 8-14, and 2,403 mg/day from day 15 onward, with administration with food. The patent does not broadly claim pirfenidone, all IPF treatment, or every dosing schedule.

The patent was assigned to InterMune, Inc., the developer of Esbriet. It issued on April 13, 2010, from an application filed December 20, 2007, and has a listed expiration date of December 20, 2027, subject to the controlling patent-term records and any applicable adjustments.[1]

What does U.S. Patent 7,696,236 protect?

The patent protects a clinical dosing protocol for pirfenidone treatment of IPF. The independent claims require the following elements:

Claim element	Required limitation
Drug	Pirfenidone
Disease	Idiopathic pulmonary fibrosis
Dosage form	Oral capsules
Capsule strength	267 mg pirfenidone per capsule
Days 1-7	One capsule three times daily, totaling 801 mg/day
Days 8-14	Two capsules three times daily, totaling 1,602 mg/day
Day 15 onward	Three capsules three times daily, totaling 2,403 mg/day
Administration instruction	Take the doses with food
Claimed benefit in dependent claims	Reduced photosensitivity reactions, approximately 12% incidence in claims 3, 5, and 7

Claim 1 is the principal treatment-method claim. Claims 4 and 6 independently restate the regimen in the context of reducing photosensitivity events and improving treatment of IPF. Claims 2, 3, 5, and 7 narrow the claims by adding the photosensitivity-reduction limitation and, in some cases, the approximately 12% result.

The patent therefore protects a regimen rather than the active pharmaceutical ingredient itself.

How broad are the claims of Patent 7,696,236?

The claims are commercially important but structurally narrow. A potentially infringing regimen generally must satisfy all material limitations of an asserted claim.

Claim 1 scope

Claim 1 requires:

Treatment of a patient with IPF.
Pirfenidone administration.
The precise 267-mg capsule strength.
The three-step escalation schedule.
The relevant calendar periods.
Administration with food.

A product label that instructs patients to follow the same schedule creates the clearest infringement risk. A label that omits the schedule, uses a different titration period, or does not instruct administration with food may create a noninfringement position, although actual prescribing and promotional conduct could remain relevant.

The phrase "at least day fifteen" means that the third dosing stage begins on day 15 and continues thereafter. It does not require the patient to receive exactly three capsules three times daily for a fixed endpoint.

Claims 2 and 3 scope

Claim 2 depends on claim 1 and adds the stated purpose or result of reducing photosensitivity reactions. Claim 3 further recites an incidence of approximately 12%.

The "about 12%" limitation may be difficult to apply as a precise numerical boundary. Courts generally assess numerical terms in context, including the specification, experimental data, and the meaning a skilled person would assign to "about." The limitation may also raise proof issues because the incidence rate can vary with patient population, exposure to sunlight, adherence, concomitant medication, and study design.

Claims 4 and 6 scope

Claims 4 and 6 are independent method claims directed to reducing photosensitivity reactions or improving treatment of IPF. They repeat the same dosing schedule and food instruction.

Their practical scope is similar to claim 1, but their stated therapeutic objective may affect infringement analysis. A defendant could argue that a product label instructs the regimen for IPF treatment without expressly directing treatment for the purpose of reducing photosensitivity. A patent owner could respond that the claimed result is inherent in, or necessarily achieved by, the prescribed regimen.

Claims 5 and 7 scope

Claims 5 and 7 add the approximately 12% incidence limitation. These are narrower than claims 4 and 6 and may be harder to establish if the clinical data do not consistently produce a result within the claimed range.

What is the patent’s prosecution and expiration timeline?

Event	Date
Earliest priority date identified in the patent family	December 21, 2006
U.S. nonprovisional filing	December 20, 2007
U.S. publication	June 25, 2009
Patent grant	April 13, 2010
Patent term measured from nonprovisional filing	December 20, 2027
FDA approval of Esbriet for IPF	October 15, 2014
Orphan-drug exclusivity for the original approval	Through October 15, 2021
Listed patent expiry	December 20, 2027

Patent 7,696,236 is a pre-URAA utility patent application filed after June 8, 1995. Its ordinary term is 20 years from the earliest effective U.S. nonprovisional filing date, rather than 17 years from grant.[1]

The FDA’s seven-year orphan-drug exclusivity for Esbriet expired in 2021. That exclusivity blocked approval of another sponsor’s same drug for the same indication during the protected period, but it did not extend the patent term.[2]

What is the Orange Book status of Patent 7,696,236?

Patent 7,696,236 has been listed in the FDA Orange Book for Esbriet, the Roche/Genentech product containing pirfenidone. The listing is a method-of-use patent associated with the approved IPF indication and the patented administration regimen.[3]

An Orange Book listing does not establish that every claim is valid or infringed. It requires an ANDA applicant to address the listed patent through one of the statutory certification pathways:

Paragraph I: no patent information has been submitted;
Paragraph II: the patent has expired;
Paragraph III: the applicant will wait until patent expiration; or
Paragraph IV: the patent is invalid, unenforceable, or will not be infringed.

A Paragraph IV certification can trigger patent litigation if the NDA holder or patent owner files suit within the statutory 45-day period. The filing of litigation generally creates a 30-month stay of final ANDA approval, subject to statutory exceptions and court action.[4]

When does pirfenidone lose patent exclusivity?

The principal listed patent expiration date for Patent 7,696,236 is December 20, 2027. That date is distinct from the expiration of regulatory exclusivity.

Protection	Type	Relevant date
Patent 7,696,236	Dose-escalation and food-administration method	December 20, 2027
Esbriet orphan exclusivity	FDA regulatory exclusivity	Expired October 15, 2021
Pirfenidone active-ingredient protection	Earlier compound protection	Expired before the Esbriet approval
Generic entry	Subject to applicable listed patents and litigation	Potentially before or after December 20, 2027, depending on certifications and settlement terms

Because the patent claims a method of use, an ANDA applicant may seek approval with a section viii statement omitting the patented method from the proposed labeling if the remaining approved uses are legally separable. If the patented method is inseparable from the approved IPF use, the applicant may need to challenge the patent through a Paragraph IV certification or wait until expiration.[4]

What patents are associated with the Esbriet and pirfenidone patent estate?

The commercial estate is broader than Patent 7,696,236. It includes patents directed to treatment methods, dosing, formulations, and related pharmaceutical uses. The exact enforceability of each patent depends on claim construction, prosecution history, Orange Book listing, and any terminal disclaimers.

Patent or protection category	Subject matter	Commercial significance
U.S. 7,696,236	Initial dose escalation, food administration, and reduced photosensitivity	Directly targets the marketed initiation regimen
Related U.S. method patents	Pirfenidone treatment of pulmonary fibrosis and dosing protocols	May create overlapping method-of-use barriers
Formulation patents	Tablet or capsule composition, excipients, release properties, or dosage forms	Can affect substitution with a materially different product
Manufacturing patents	Processes for producing pirfenidone or pharmaceutical compositions	May restrict particular manufacturing routes but not necessarily all generic manufacture
Regulatory exclusivity	Orphan-drug exclusivity for Esbriet	Expired in 2021 and separate from patent rights

Patent 7,696,236 is most relevant where a competitor proposes the same 267-mg capsule schedule used in the Esbriet labeling. A formulation or manufacturing patent would present a different infringement question and would not automatically extend the reach of the regimen claims.

What formulations are protected by Patent 7,696,236?

The claims expressly require capsules comprising 267 mg of pirfenidone. They do not claim every pirfenidone formulation.

The patent’s practical formulation limitations include:

oral administration;
capsule delivery;
267 mg of pirfenidone per capsule;
one, two, or three capsules per administration depending on the escalation phase; and
administration with food.

A generic using 267-mg capsules and copying the same titration instructions would face the strongest claim risk. A product using 801-mg tablets could raise a literal-scope issue because the claims describe 267-mg capsules. That distinction would not necessarily eliminate infringement risk under the doctrine of equivalents, particularly if the product performs the same function in substantially the same way with substantially the same result. The equivalence analysis would depend on prosecution history and the scope surrendered during examination.

An 801-mg tablet product also could be subject to separate formulation or method patents, even if it avoids the literal capsule limitation in Patent 7,696,236.

How strong is the patent estate for pirfenidone?

Patent 7,696,236 has meaningful commercial strength because it corresponds closely to the FDA-approved Esbriet initiation schedule. Its strength is reduced by the narrowness of its limitations.

Strengthening factors

The claim recites an operational regimen that can be copied directly in an ANDA label.
The schedule is specific and readily identifiable.
The food instruction is included in the approved product labeling.
The patent covers the principal clinical initiation sequence rather than an abstract treatment objective.
Claims 1, 4, and 6 provide multiple independent claim theories.

Limiting factors

The patent does not claim pirfenidone itself.
The patent does not cover every IPF regimen.
The capsule-strength and food-instruction requirements provide potential design-around arguments.
Claims tied to an approximately 12% photosensitivity incidence may present proof and construction issues.
A generic may attempt a section viii carve-out or use a different dosage form and labeling strategy.
Patent expiration is fixed in 2027 absent a legally effective term adjustment.

The strongest enforcement scenario is a generic label that reproduces the Esbriet label’s 14-day titration instructions and food administration language. The weaker scenario is a product with a materially different dosage form, different titration schedule, or labeling that omits the patented use.

Which companies are challenging pirfenidone patents?

Pirfenidone is a small-molecule drug, so competitive entry occurs through ANDAs rather than biosimilar applications. Publicly identified generic applicants and litigation records must be matched to the specific patent, NDA, dosage form, and certification at issue.

The relevant competitive groups are:

Generic pharmaceutical companies filing ANDAs for 267-mg capsules or tablets.
Companies pursuing 801-mg tablets, which may seek to avoid the capsule-specific language.
Applicants relying on section viii labeling carve-outs.
Manufacturers using alternative excipient systems or production processes.
Authorized or licensed generic suppliers, if established under private settlement arrangements.

The Orange Book certification for an ANDA is not equivalent to a judicial finding. A Paragraph IV assertion means the applicant has alleged invalidity, unenforceability, or noninfringement. It does not determine the outcome.[4]

What patent litigation affects Patent 7,696,236?

The principal litigation risk arises when an ANDA applicant certifies that Patent 7,696,236 is invalid, unenforceable, or not infringed. The NDA holder or patent owner may then file a Hatch-Waxman action in federal district court.

The central litigation issues would likely include:

Issue	Likely dispute
Claim construction	Meaning of “providing,” “initial dose escalation regimen,” “at least day fifteen,” and “with food”
Infringement	Whether the proposed label directs every claimed step
Therapeutic-purpose language	Whether treatment of IPF inherently satisfies the photosensitivity-reduction claims
Numerical limitation	Meaning and proof of “about 12%”
Validity	Written description, enablement, obviousness, and anticipation
Inducement	Whether label instructions encourage physicians and patients to perform the claimed method
Carve-out strategy	Whether the patented method can be removed from the proposed labeling
Patent-term defense	Whether the patent has expired or has a different effective expiration date

A settlement could provide an agreed generic launch date before December 20, 2027, but settlement terms are often confidential. A license, authorized-generic arrangement, or delayed-entry agreement could materially change commercial exposure without invalidating the patent.

Are biosimilar risks relevant to pirfenidone?

No. Pirfenidone is a chemically synthesized small molecule, not a biologic. Competitors file ANDAs under section 505(j) of the Federal Food, Drug, and Cosmetic Act, not abbreviated biologics license applications under the biosimilar pathway.

The relevant risks are generic substitution, Paragraph IV litigation, section viii carve-outs, formulation design-arounds, and potential authorized-generic competition. The FDA Purple Book is not the relevant exclusivity database for pirfenidone.[5]

What generic launch scenarios exist for pirfenidone?

Scenario 1: Full-label generic launch after patent expiry

A generic applicant waits until December 20, 2027, or the legally controlling expiration date, and markets a product with the full IPF indication and the same dose-escalation instructions.

Scenario 2: Paragraph IV launch after a favorable judgment

The applicant challenges Patent 7,696,236 and launches before expiration if the patent is invalidated, held unenforceable, or found not infringed, subject to any other applicable patents.

Scenario 3: Carved-out labeling

The applicant removes the patented method from its labeling under section viii. This strategy depends on whether the FDA-approved indication and dosing instructions can be separated from the patented regimen.

Scenario 4: Alternative dosage form

The applicant markets an 801-mg tablet or another dosage form that does not literally satisfy the 267-mg capsule limitation. This reduces literal infringement exposure but does not eliminate potential equivalents or separate formulation-patent risk.

Scenario 5: Licensed early entry

The generic enters under a confidential or public license, potentially through an authorized-generic structure or negotiated launch date.

What is the revenue exposure from Patent 7,696,236?

The patent protects an important initiation regimen, but it does not independently protect all sales of pirfenidone. Its revenue impact depends on whether a competing label must reproduce the patented dosing instructions to obtain approval for IPF.

Esbriet is approved in 267-mg capsules and 801-mg tablets. The 267-mg capsule schedule is particularly relevant to Patent 7,696,236 because the claims expressly require that strength and capsule format. A competitor able to launch an 801-mg tablet with legally distinct labeling could reduce the patent’s practical control over the market even before the listed expiration date.

Revenue exposure therefore depends on:

the number of valid and enforceable Orange Book patents;
the ability to obtain a section viii carve-out;
whether generic applicants use 267-mg capsules or 801-mg tablets;
the outcome of Paragraph IV litigation;
the existence of settlement or license agreements;
payer substitution practices; and
the commercial availability of authorized generics.

Key Takeaways

U.S. Patent 7,696,236 claims a specific pirfenidone initiation schedule for IPF.
The schedule is 801 mg/day for days 1-7, 1,602 mg/day for days 8-14, and 2,403 mg/day from day 15 onward.
The claims require 267-mg oral capsules and administration with food.
The patent does not claim pirfenidone generally or every IPF treatment method.
Claims 3, 5, and 7 add an approximately 12% photosensitivity-incidence limitation.
The listed patent expiration date is December 20, 2027.
Esbriet’s orphan-drug exclusivity expired October 15, 2021.
Generic risk is governed by ANDA strategy, Paragraph IV certifications, section viii carve-outs, and possible formulation design-arounds.
Biosimilar law does not apply because pirfenidone is a small-molecule drug.
The highest infringement risk arises from a generic label copying the marketed 267-mg capsule titration regimen and food instructions.

FAQs

Does Patent 7,696,236 cover 801-mg pirfenidone tablets?

Not literally on the face of the provided claims. The claims require 267-mg capsules. An 801-mg tablet could still face risk under the doctrine of equivalents or separate patents, but the capsule limitation provides a potential noninfringement argument.

Can a generic sell pirfenidone before December 20, 2027?

Potentially. Early entry could occur through a successful Paragraph IV challenge, a section viii carve-out, a license, an authorized-generic arrangement, or a settlement with an agreed launch date.

Does the patent protect the 2,403-mg maintenance dose?

It protects the method only when that dose follows the claimed first and second escalation periods and is administered as three 267-mg capsules three times daily. It does not broadly claim every way of administering 2,403 mg/day.

Is the “about 12%” photosensitivity limitation required for infringement?

It is required for claims 3, 5, and 7, but not for claims 1, 2, 4, or 6. The numerical limitation does not narrow every claim in the patent.

Is pirfenidone subject to biosimilar substitution?

No. Pirfenidone is a small-molecule drug approved through the NDA pathway. Generic applicants use ANDAs, and pharmacy substitution is governed by applicable state law and FDA therapeutic-equivalence determinations.

References

United States Patent and Trademark Office. (2010). U.S. Patent No. 7,696,236, Methods for treating pulmonary fibrosis. https://patents.google.com/patent/US7696236B2/en
U.S. Food and Drug Administration. (2014). FDA approves Esbriet to treat idiopathic pulmonary fibrosis. https://www.fda.gov/news-events/press-announcements/fda-approves-esbriet-treat-idiopathic-pulmonary-fibrosis
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book. https://www.accessdata.fda.gov/scripts/cder/ob/
Legal Information Institute. (n.d.). 21 U.S.C. § 355: New drugs. Cornell Law School. https://www.law.cornell.edu/uscode/text/21/355
U.S. Food and Drug Administration. (2024). Purple Book: Database of licensed biological products. https://purplebooksearch.fda.gov/

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Legacy	ESBRIET	pirfenidone	CAPSULE;ORAL	022535-001	Oct 15, 2014	AB	RX	Yes	Yes	⤷ Start Trial	⤷ Start Trial				DOSE ESCALATION OVER 14 DAYS FOR TREATMENT OF IDIOPATHIC PULMONARY FIBROSIS	⤷ Start Trial
>Applicant	>Tradename	>Generic Name	>Dosage	>NDA	>Approval Date	>TE	>Type	>RLD	>RS	>Patent No.	>Patent Expiration	>Product	>Substance	>Delist Req.	>Patented / Exclusive Use	>Submissiondate

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	E506060	⤷ Start Trial
Canada	2667654	⤷ Start Trial
Cyprus	1111699	⤷ Start Trial
Germany	602007014113	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 7,696,236

Which drugs does patent 7,696,236 protect, and when does it expire?

Summary for Patent: 7,696,236