United States Patent 7,981,938: Colchicine Gout-Flare Treatment Scope, Expiration, Litigation, and Generic Risk

U.S. Patent No. 7,981,938 protects a specific colchicine rescue regimen for a patient who is already taking colchicine prophylactically. The claimed sequence is 1.2 mg oral colchicine at flare onset, 0.6 mg one hour later, followed by resumption of 0.6 mg or 1.2 mg daily prophylaxis after a 12-hour interval.

The patent does not broadly cover colchicine, gout treatment, prophylaxis, or all acute-flare dosing. Its enforceability depends on proving every element of the method, including the patient’s existing prophylaxis, the exact dose sequence, the timing, the oral route, and continuation of prophylaxis after 12 hours. The patent was listed for Colcrys in the FDA Orange Book and has an estimated expiration date in 2029, subject to the applicable patent-term calculation and regulatory records. [1, 2]

What does U.S. Patent 7,981,938 protect?

The patent protects a method of treating an acute gout flare in a patient undergoing colchicine prophylaxis. The supplied claim requires the following sequence:

Claim element	Required limitation
Disease	Gout flare
Patient status	Patient is already undergoing colchicine prophylactic treatment of gout flares
First dose	1.2 mg oral colchicine at onset of the acute flare
Second dose	0.6 mg oral colchicine about one hour later
Waiting period	No continuation of prophylaxis until after waiting 12 hours
Maintenance	Resume 0.6 mg or 1.2 mg oral colchicine daily
Claim format	Method claim using “consisting of”

The practical invention is a low-dose acute-flare regimen integrated with ongoing prophylaxis. It avoids the older high-dose colchicine regimen, which historically involved repeated dosing over several hours and produced greater gastrointestinal toxicity.

The FDA-approved Colcrys labeling describes a low-dose acute treatment regimen of 1.2 mg followed by 0.6 mg one hour later, with a maximum recommended acute-treatment dose of 1.8 mg over one hour. The label also addresses prophylaxis and dosing limitations. [3]

How broad is the claim scope?

The claim is narrower than a general patent on colchicine for gout. It requires a defined clinical context and dosing sequence.

Required patient condition

The patient must have an acute gout flare while already receiving colchicine prophylaxis. A patient treated for a first gout flare without prior prophylactic colchicine use may not meet this limitation.

The claim also requires that the prophylaxis be directed to prevention of gout flares. A patient taking colchicine for another indication, such as familial Mediterranean fever, would not inherently satisfy the claim.

Required dosing sequence

The first dose must be 1.2 mg orally, followed by 0.6 mg orally about one hour later. A regimen using 0.6 mg followed by 0.6 mg, a single 1.8 mg dose, or repeated 0.6 mg doses may fall outside the literal claim.

The total acute dose is 1.8 mg. The claim is directed to timing and sequencing, not merely to the total amount administered.

Required continuation of prophylaxis

After the acute treatment, the patient must wait 12 hours and then continue daily prophylaxis at 0.6 mg or 1.2 mg. The claim therefore reaches beyond the first two doses. A product label or clinical protocol that instructs patients to resume daily colchicine prophylaxis after the specified interval can create infringement exposure.

“About” and clinical timing

The terms “about one hour” and “after waiting 12 hrs” provide some timing flexibility. They do not necessarily require administration at exactly 60 minutes or exactly 12 hours. The scope would depend on claim construction, specification support, prosecution history, clinical practice, and the facts of the accused regimen.

What does the “consisting of” language mean?

“Consisting of” is a closed transitional phrase. It generally excludes additional method steps that materially change the claimed regimen, while permitting incidental actions that do not alter the required treatment sequence.

The claim therefore presents two issues:

The accused method must include all stated steps.
Additional active dosing steps may create a noninfringement argument if they materially alter the claimed regimen.

A regimen that includes the claimed 1.2 mg dose and 0.6 mg dose but adds another colchicine dose before the 12-hour interval could raise both infringement and claim-construction questions. The answer would depend on whether the added dose is viewed as inconsistent with the closed claim or as an incidental step that does not remove the method from the claim.

What are the key infringement elements?

A patent owner would need to establish that the accused method satisfies each limitation, directly or through induced infringement theories.

Direct method infringement

For direct infringement, the relevant actor must perform the claimed method. In pharmaceutical cases, the prescribing physician, healthcare provider, or patient may be relevant depending on the theory and evidence. A generic manufacturer ordinarily does not itself administer the drug, so induced infringement under 35 U.S.C. § 271(b) can become central.

Induced infringement risk

A generic manufacturer may face risk if its labeling instructs physicians and patients to perform the patented regimen. Evidence may include:

The approved prescribing information.
Patient instructions.
Dosage tables.
Promotional material.
Medication guides.
Pharmacy counseling materials.
Statements in an ANDA or regulatory submission.

The Supreme Court’s decision in GlaxoSmithKline LLC v. Teva Pharmaceuticals USA, Inc. illustrates the importance of labeling language in induced-infringement disputes involving pharmaceutical methods. [4]

Elements that create design-around opportunities

A potential design-around could attempt to change:

The prophylactic drug or dose.
The first acute dose.
The one-hour interval.
The 12-hour waiting interval.
The daily maintenance dose.
The route of administration.
The instruction to resume prophylaxis.

The commercial viability of a design-around is limited where the FDA-approved regimen itself tracks the patented dosing sequence.

What is the patent’s expiration date?

The patent was issued on July 19, 2011. Public patent records and Orange Book listings associate the patent with an expiration date in 2029, commonly reported as October 29, 2029. [1, 2]

Event	Date or status
Patent issued	July 19, 2011
Patent number	U.S. 7,981,938
Product association	Colcrys, colchicine
FDA Orange Book status	Listed method-of-use patent
Reported expiration	October 29, 2029
Relevant product	Oral colchicine tablets
Regulatory pathway	NDA 022352

Patent term must be determined from the USPTO patent record, including any patent-term adjustment, terminal disclaimer, patent-term extension, or later legal event. The Orange Book provides the principal commercial reference for listed drug patents, but it is not a substitute for reviewing the underlying patent file and term calculation. [1, 2]

What is the Orange Book status of U.S. 7,981,938?

The patent was listed for Colcrys, the colchicine product approved under NDA 022352. The listing is directed to a method of use rather than a composition-of-matter claim covering colchicine itself.

The Orange Book distinction matters because an ANDA applicant may be required to address the listed patent through:

Paragraph I certification, if the patent information is not applicable.
Paragraph II certification, if the patent has expired.
Paragraph III certification, accepting approval after patent expiration.
Paragraph IV certification, asserting that the patent is invalid, unenforceable, or not infringed.

A Paragraph IV certification can trigger notice and patent litigation under the Hatch-Waxman framework. [5]

When does colchicine lose regulatory exclusivity?

Colcrys received FDA approval in July 2009. The product’s principal regulatory exclusivity periods expired before the reported 2029 patent expiration. Regulatory exclusivity and patent exclusivity are separate.

Protection type	Practical effect
NDA approval	Established FDA-approved oral colchicine product
New-drug exclusivity	Expired before the principal patent term
Orange Book patent	Can delay or complicate ANDA approval
Paragraph IV litigation	Can impose a 30-month stay if statutory requirements are met
Patent expiration	Removes the listed patent as a continuing Hatch-Waxman barrier

The 30-month stay is not an automatic extension of the patent term. It is a regulatory approval stay triggered by timely patent litigation after a qualifying Paragraph IV notice. [5]

Which companies have challenged Colcrys patents?

Generic colchicine companies have pursued ANDA filings and patent challenges involving Colcrys patents, including manufacturers such as Hikma Pharmaceuticals, Zydus Pharmaceuticals, Amneal Pharmaceuticals, and Rising Pharmaceuticals. The specific patents asserted, settlement terms, and launch rights have varied by defendant and time period.

Colchicine litigation has also produced antitrust and market-access disputes concerning the transition from older unapproved colchicine products to FDA-approved Colcrys. In In re Colchicine Antitrust Litigation, plaintiffs challenged conduct involving the withdrawal of older products and market exclusivity strategies. The case illustrates the commercial significance of Colcrys patent listings beyond a single infringement action. [6]

A company-by-company assessment requires separating:

ANDA filing date.
Paragraph IV notice date.
Patents asserted.
Court district.
Litigation outcome.
Settlement date.
Authorized or licensed launch date.
Whether the settlement covered 7,981,938 specifically.

What patent litigation affects U.S. 7,981,938?

The principal litigation risk concerns whether a generic label directs the patented regimen. The patent owner may argue that the label encourages physicians to use the exact 1.2 mg-plus-0.6 mg regimen in patients already receiving prophylaxis and instructs patients to resume prophylaxis after 12 hours.

The generic applicant may respond that:

The label does not require prophylactic use before the flare.
The label permits treatment in patients outside the claim.
The label does not require resumption after 12 hours.
The phrase “about one hour” is not met.
The patent is invalid for anticipation or obviousness.
The claimed regimen was disclosed in the prior art.
The method lacks adequate written description or enablement.
The label contains a legally sufficient carve-out.

The patent’s strongest infringement theory is likely a label-based inducement case where the generic label reproduces the claimed sequence without a meaningful carve-out. Its principal validity risk is whether prior art disclosed low-dose colchicine treatment in a prophylaxis patient with substantially the same timing and continuation instructions.

How strong is the patent estate around Colcrys?

U.S. 7,981,938 is one component of a broader colchicine patent and regulatory estate. The commercial protection has included method-of-use patents directed to acute-flare treatment, prophylaxis, dosing, and related administration protocols.

Estate component	Protection focus
U.S. 7,981,938	Acute flare treatment during colchicine prophylaxis
Other Colcrys method patents	Acute dosing and prophylactic use
FDA labeling	Approved indications, dose restrictions, contraindications
Manufacturing controls	Product quality, formulation, and supply continuity
Trademark rights	Colcrys brand identity
Regulatory history	NDA approval and product-specific labeling

The estate is stronger against a generic that adopts the branded label without modification. It is weaker against a product whose label omits the patented prophylaxis-resumption instruction and does not encourage the full claimed sequence.

What formulations are protected by the patent?

The claim is directed to administration of oral colchicine. It does not require a particular tablet formulation, excipient system, release profile, coating, particle size, or manufacturing process.

Accordingly, the claim can potentially cover different oral colchicine tablet formulations if they are used according to the claimed regimen. It does not, on its face, cover:

Intravenous colchicine.
A transdermal colchicine product.
A non-colchicine anti-inflammatory.
A formulation used outside the claimed dosing sequence.
Manufacturing of colchicine tablets as such.

The absence of a formulation limitation increases the method claim’s potential reach across conventional immediate-release oral tablets. It also means that a formulation patent and this method patent present different infringement questions.

Are biosimilar risks relevant?

No. Colchicine is a small-molecule drug, not a biologic. The relevant competitive pathway is an ANDA for a generic drug under section 505(j) of the Federal Food, Drug, and Cosmetic Act, not a biosimilar application under the Biologics Price Competition and Innovation Act.

The main regulatory issues are therapeutic equivalence, labeling, patent certifications, and potential substitution under state pharmacy laws. [5, 7]

What generic launch scenarios exist?

Launch after patent expiry

A generic can launch after the listed patent expires, assuming FDA approval and satisfaction of other patent and regulatory requirements. This is the lowest litigation-risk scenario.

Launch after successful Paragraph IV litigation

A generic may launch before the reported patent expiration if the patent is held invalid, unenforceable, or not infringed, or if the parties resolve the dispute on terms permitting launch.

Authorized generic or settlement launch

A settlement may establish an agreed launch date, license, or authorized-generic arrangement. The commercial value depends on how much time remains before the patent expiration date and whether multiple generic entrants can launch simultaneously.

Label carve-out

A generic may seek approval with a section viii statement or other labeling strategy that omits the patented use. The strategy is difficult where the same dosing instructions are clinically central to the approved indication and cannot be removed without undermining the product’s approved use.

How does this patent compare with a composition patent?

Issue	U.S. 7,981,938	Composition-of-matter patent
Subject matter	Treatment method	Chemical compound or active ingredient
Claim dependence	Depends on patient behavior and dosing	Usually depends on product identity
Proof burden	Must prove each treatment step	Must prove product contains claimed compound
Label relevance	Very high	High but usually more direct
Design-around potential	Often greater	Usually lower
Colchicine coverage	Specific regimen	Broad compound coverage if valid
Generic risk	Label and induced infringement	Product-level infringement

The patent does not prevent all colchicine sales. It targets a particular clinical protocol.

Key Takeaways

U.S. Patent 7,981,938 covers a specific colchicine rescue regimen for patients already receiving colchicine prophylaxis.
The required sequence is 1.2 mg orally at flare onset, 0.6 mg orally about one hour later, then resumption of 0.6 mg or 1.2 mg daily after 12 hours.
The “consisting of” language makes the claimed regimen comparatively closed and limits the role of additional treatment steps.
The patent is a method-of-use patent, not a broad colchicine composition or manufacturing patent.
Colchicine is a small molecule, so biosimilar law is not relevant. Generic applicants use the ANDA pathway.
The patent was listed for Colcrys and is commonly reported to expire on October 29, 2029.
The principal generic risk is induced infringement based on an ANDA label that instructs the patented dosing sequence.
The principal validity issues are likely anticipation, obviousness, written description, enablement, and the scope of the clinical prior art.
A label carve-out may reduce risk, but its availability depends on whether the patented use can be omitted without undermining the approved labeling.
Patent-specific settlement terms and launch rights must be assessed defendant by defendant.

FAQs About U.S. Patent 7,981,938

Does U.S. 7,981,938 cover all use of colchicine for gout?

No. It covers the specified acute-flare regimen in a patient already receiving colchicine prophylaxis, followed by delayed resumption of daily prophylaxis.

Is the patent directed to Colcrys tablets only?

No. The claim requires oral colchicine but does not appear limited to the Colcrys brand or to a particular excipient or tablet formulation.

Can a generic sell colchicine before October 2029?

Yes, in principle, if it obtains FDA approval through an approved patent certification, defeats the patent, reaches a settlement permitting earlier launch, or otherwise avoids infringement. The commercial outcome depends on the applicable Orange Book patents and litigation.

Does a patient’s failure to follow the regimen eliminate patent risk?

It may affect proof of direct or induced infringement, but patient adherence is only one part of the analysis. Prescribing instructions, pharmacy communications, and manufacturer labeling can be material.

Is U.S. 7,981,938 still commercially important after Colcrys exclusivity ended?

Yes. Regulatory exclusivity and patent protection are separate. A listed method patent can delay or restrict generic approval even after the product’s statutory exclusivity has expired.

References

United States Patent and Trademark Office. (2011). U.S. Patent No. 7,981,938.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
U.S. Food and Drug Administration. (2009). Colcrys prescribing information, NDA 022352.
GlaxoSmithKline LLC v. Teva Pharmaceuticals USA, Inc., 7 F.4th 1320 (Fed. Cir. 2021), vacated and remanded, 143 S. Ct. 661 (2023).
Federal Food, Drug, and Cosmetic Act, 21 U.S.C. § 355(j).
In re Colchicine Antitrust Litigation, 2015 WL 1038326 (E.D. Pa. Mar. 10, 2015).
U.S. Food and Drug Administration. (2024). Abbreviated new drug application process.

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Takeda Pharms Usa	COLCRYS	colchicine	TABLET;ORAL	022352-001	Jul 29, 2009		DISCN	Yes	No	⤷ Start Trial	⤷ Start Trial				A METHOD FOR TREATMENT OF GOUT FLARES DURING PROPHYLAXIS	⤷ 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

Details for Patent: 7,981,938

Which drugs does patent 7,981,938 protect, and when does it expire?

Summary for Patent: 7,981,938