US Patent 6,133,310: Scope, Claims, Expiration, and Ivermectin Rosacea Patent Landscape

US Patent 6,133,310 covers a historical topical ivermectin treatment regimen for acne rosacea and rosacea. Its claims require specific dosage forms, ivermectin concentrations, treatment intervals, and, for the cream claims, particular carrier ingredients. The patent issued on October 17, 2000, and its enforceable term expired no later than November 13, 2017, based on the underlying nonprovisional filing date. It does not currently block generic or branded ivermectin products.

What does US Patent 6,133,310 cover?

US Patent 6,133,310, titled “Treatment of Rosacea with Ivermectin,” is a method-of-treatment patent. It does not claim ivermectin as a compound, a general topical composition, a manufacturing process, or every use of ivermectin against rosacea.[1]

The claims supplied contain typographical variations such as “invermectin” and “invemectin.” The relevant drug is ivermectin. The patent’s scope is best analyzed using the intended term ivermectin and the patent title and specification.

Patent	Subject	Filing date	Issue date	Earliest priority	Estimated expiration
US 6,133,310	Topical ivermectin treatment of rosacea	Nov. 13, 1998	Oct. 17, 2000	Nov. 13, 1997	Nov. 13, 2017

The patent uses “consisting of” in the principal method claims. That transitional language generally limits the claimed method to the recited steps, although ordinary ancillary acts necessary to perform those steps may not be excluded. The claims also contain “about,” “therapeutically effective amount,” and “several months,” which introduce factual claim-construction issues.

What are the independent claims in US Patent 6,133,310?

The patent has two principal independent method claims.

Claim 1: Ivermectin lotion for acne rosacea

Claim 1 requires all of the following:

Mixing a therapeutically effective amount of ivermectin with water.
Forming a lotion.
Applying the lotion daily to an affected area for about seven days.
Repeating the application two to four times per month for several months.
Optionally applying the lotion about once per month thereafter.

The claim is directed specifically to “acne rosacea,” rather than rosacea in general. A product or treatment that uses a nonaqueous cream would not literally satisfy the “mixing ... with water to thereby form a lotion” limitation.

Claim 3: Ivermectin cream for rosacea

Claim 3 requires:

Mixing a therapeutically effective amount of ivermectin with a pharmaceutically acceptable carrier.
Forming a cream.
Applying the cream daily for about seven days.
Repeating application two to four times per month for several months.
Optionally applying the cream about once per month thereafter.

Claim 3 is broader as to disease terminology because it recites “rosacea,” not “acne rosacea.” It is also broader as to the carrier because the carrier is not limited to the ingredients listed in dependent claim 5.

What concentration does the patent require?

Claims 2 and 4 impose a minimum ivermectin concentration of 750 micrograms per milliliter or per cubic centimeter.

Claim	Concentration limitation	Approximate percentage
Claim 2	At least 750 mcg/mL	At least 0.075% w/v
Claim 4	At least 750 mcg/cc	At least 0.075% w/v

A concentration of 750 mcg/mL equals 0.75 mg/mL. In a formulation with an approximate density of 1 g/mL, this is approximately 0.075% w/w.

Soolantra cream contains 1% ivermectin, or approximately 10 mg/g. That concentration is materially above the minimum concentration in claims 2 and 4. Concentration alone, however, is not enough to satisfy the claims. The formulation and treatment schedule must also meet the other limitations.

What formulations are protected by US Patent 6,133,310?

The patent distinguishes between a lotion and a cream.

Lotion limitations

Claims 1 and 2 require ivermectin to be mixed with water to form a lotion. The claims do not identify a fixed excipient system, a particular pH, a particle size, a viscosity, or a specific percentage of water.

A formulation could therefore fall within the literal wording of these claims if it:

Contains ivermectin;
Uses water to form a lotion;
Meets the minimum concentration in claim 2, if claim 2 is asserted; and
Is used according to the specified application schedule.

The claim does not cover every aqueous ivermectin product independently of the treatment regimen.

Cream limitations

Claims 3 through 5 concern a cream formed with a pharmaceutically acceptable carrier.

Claim 5 narrows the carrier to:

Propylene glycol;
Sodium lauryl sulfate;
Xanthan gum; or
Combinations of those ingredients.

The claim text supplied spells “xanthum gum,” but the conventional ingredient name is xanthan gum. A claim interpretation would likely consider the context and specification when addressing that spelling variation.

Claim 5 is narrow because it requires the concentration limitation from claim 4 and one of the listed carrier systems. It does not claim every cream containing ivermectin.

Does Soolantra fall within the technical scope of the patent?

Soolantra is a 1% ivermectin cream approved by the FDA for the treatment of inflammatory lesions of rosacea in adults.[2] Its 1% concentration exceeds the 0.075% minimum recited in claim 4.

That overlap does not establish infringement of US 6,133,310 because the patent requires a particular method of use. The relevant questions would include:

Whether the product is used as a cream;
Whether the cream uses a carrier covered by claim 5;
Whether the patient applies it daily for about seven days;
Whether the patient repeats treatment two to four times per month for several months; and
Whether any asserted claim remained enforceable during the relevant conduct.

The last issue is dispositive today. US 6,133,310 has expired. The patent cannot support a current patent-infringement claim against Soolantra, a generic ivermectin cream, or another product.

Soolantra’s commercial formulation and regulatory approval are associated principally with later Galderma patent families and regulatory exclusivities, not with continuing enforceability of US 6,133,310.

When did US Patent 6,133,310 lose exclusivity?

The patent term expired in 2017.

For a utility patent filed after June 8, 1995, the basic term is 20 years from the earliest effective nonprovisional filing date, subject to patent-term adjustment, patent-term extension, terminal disclaimers, and other statutory adjustments.[3]

US 6,133,310 identifies a November 13, 1997 priority filing and a November 13, 1998 U.S. nonprovisional filing. On that record, the ordinary 20-year term ran from November 13, 1997 and ended on November 13, 2017. Patent-term adjustment could have moved the date forward, but it could not make the patent commercially relevant today unless an unusual term extension applied. No current enforceable term remains.

Event	Date
Earliest identified priority date	Nov. 13, 1997
U.S. nonprovisional filing	Nov. 13, 1998
Patent issued	Oct. 17, 2000
Ordinary 20-year term endpoint	Nov. 13, 2017
Current enforceable status	Expired

What is the Orange Book status of US Patent 6,133,310?

US 6,133,310 is not a current Orange Book barrier for Soolantra or generic ivermectin cream.

The Orange Book lists patents submitted by an NDA holder for an approved drug product. The FDA’s Orange Book patent listings can include drug-substance, drug-product, and method-of-use patents, but listing status does not extend an expired patent or create rights beyond the patent’s actual scope.[4]

Soolantra was approved under NDA 206255 on December 17, 2014.[2] The relevant Orange Book patent estate for Soolantra consists of later patents associated with the approved product and its formulations or uses. US 6,133,310 is an earlier historical patent and is not a continuing Orange Book exclusivity right.

Are there Paragraph IV challenges to US Patent 6,133,310?

A Paragraph IV certification against US 6,133,310 would have no practical current value because the patent has expired.

Under the Hatch-Waxman framework, an ANDA applicant may certify that a listed patent is invalid, unenforceable, or will not be infringed. A Paragraph IV notice can trigger litigation and, in some circumstances, a 30-month stay. Those consequences depend on a patent having a live regulatory and legal role.[5]

For US 6,133,310:

The patent’s term has expired.
A certification that a generic will not infringe the expired patent would be commercially immaterial.
The patent cannot support a current 30-month stay against approval of an ANDA.
Any present generic challenge would focus on later, unexpired Soolantra-related patents.

Which companies have challenged the Soolantra patent estate?

Generic competition to topical ivermectin cream is directed at later Galderma patents, not at the expired ’310 patent. Public patent disputes involving Soolantra have centered on ANDA applicants and later formulation or method patents associated with Galderma’s product.

The relevant competitive parties may include:

Galderma Laboratories, L.P., the Soolantra sponsor and patent-holder affiliate;
Generic dermatology companies filing ANDAs for ivermectin 1% cream;
Contract manufacturers and specialty generic companies pursuing topical semisolid products.

The critical diligence point is patent-by-patent identification of the ANDA applicant, asserted patent, Paragraph IV notice date, district-court filing, claim-construction rulings, settlement terms, and agreed launch date. Those facts cannot be attributed to US 6,133,310 merely because the patent also concerns topical ivermectin.

How strong is the patent estate for US 6,133,310?

The patent had meaningful historical value as an early method patent but has no present blocking strength.

Strength factor	Assessment
Compound coverage	None
General ivermectin composition coverage	None
Lotion coverage	Yes, but only with the claimed regimen
Cream coverage	Yes, but only with the claimed regimen
Minimum concentration	750 mcg/mL or mcg/cc in dependent claims
Specific excipient coverage	Claims 5 lists propylene glycol, sodium lauryl sulfate, and xanthan gum
Manufacturing protection	None apparent from the supplied claims
Disease coverage	Acne rosacea in claim 1; rosacea in claim 3
Current enforceability	None because the patent expired
Biosimilar relevance	None

The historical claim strength was limited by the treatment schedule. A competitor could potentially design around the claims by using a different dosage form, a different carrier, a different regimen, or a different concentration, subject to the specification and applicable law.

The patent also does not claim the modern standard Soolantra regimen as a standalone product claim. FDA labeling for Soolantra directs once-daily application to affected areas, which differs from the recurring seven-day and monthly schedule recited in US 6,133,310.[2]

Does the patent create biosimilar risk?

No. Ivermectin is a small-molecule drug, not a biologic. The relevant regulatory pathway is an ANDA for a generic drug, not a biosimilar application under the Public Health Service Act.

Generic applicants must address listed patents and exclusivities associated with the reference product. They do not need to overcome an expired method patent as a current barrier. The commercial issues are formulation sameness, bioequivalence, topical product requirements, manufacturing controls, and later unexpired patents.

What licensing deals are associated with US Patent 6,133,310?

No continuing license or royalty obligation can arise solely from an expired patent unless a separate contract contains surviving payment or other obligations. Publicly available product information does not establish that US 6,133,310 imposes a current license requirement on generic ivermectin manufacturers.

The commercial rights relevant to Soolantra are associated with Galderma’s product development, regulatory approvals, trademarks, formulations, and later patent families. An acquisition, collaboration, or license involving Soolantra would not revive the expired term of US 6,133,310.

What generic launch risks remain after expiration?

The ’310 patent creates no current launch risk. Remaining risks may arise from other sources:

Later Orange Book-listed patents for Soolantra.
Patent litigation against an ANDA applicant.
Product-specific formulation differences that prevent an ANDA from qualifying as therapeutically equivalent.
FDA requirements for topical semisolid products.
Trademark, trade dress, manufacturing, and supply-chain issues.
State substitution and pharmacy-market access.

A generic launch analysis should therefore separate:

Expired historical method patents;
Live Orange Book patents;
FDA regulatory exclusivity;
Non-Orange-Book patents;
Litigation settlements; and
Commercial manufacturing capability.

How does US 6,133,310 compare with later ivermectin patents?

Issue	US 6,133,310	Later Soolantra-related patents
Primary protection	Treatment method	Formulation, product, use, or related technical features
Drug	Ivermectin	Ivermectin, generally at or around 1% topical strength
Claim format	Method of treatment	May include composition, formulation, or method claims
Regulatory link	Historical	Directly linked to the approved Soolantra product
Expiration	2017 ordinary term endpoint	Later dates, depending on patent and term adjustments
Current blocking effect	None	Must be reviewed patent by patent
Generic challenge	Not commercially meaningful today	Paragraph IV and litigation may remain relevant
Biosimilar relevance	None	None

Key Takeaways

US Patent 6,133,310 covers topical ivermectin treatment methods for rosacea, not ivermectin itself.
Claims 1 and 2 concern an ivermectin lotion made with water.
Claims 3 through 5 concern an ivermectin cream and, in claim 5, specified carrier ingredients.
Claims 2 and 4 require at least 750 mcg/mL or mcg/cc, approximately 0.075%.
A 1% ivermectin cream is above the claimed minimum concentration, but the patent also requires the specified treatment regimen.
The patent’s ordinary term expired in 2017.
The patent is not a current Orange Book barrier and cannot support a present infringement action.
Ivermectin is a small molecule, so biosimilar rules do not apply.
Current generic-launch risk depends on later Soolantra patents, FDA requirements, and any active litigation or settlement.

FAQs About US Patent 6,133,310

Can a generic manufacturer launch ivermectin cream despite US Patent 6,133,310?

Yes. The patent has expired and does not independently prevent launch.

Does the patent claim 1% ivermectin cream?

No. It claims treatment methods with a minimum concentration in dependent claims. It does not claim a 1% ivermectin cream as a standalone composition.

Is US 6,133,310 listed for Soolantra in the Orange Book?

It is not a current Orange Book barrier for Soolantra. Later patents must be assessed separately.

Does claim 5 cover any ivermectin cream containing propylene glycol?

No. Claim 5 also incorporates the limitations of claims 3 and 4, including the rosacea treatment method, cream format, concentration threshold, and required application schedule.

Can an expired patent still affect a generic’s FDA approval?

An expired patent generally cannot support a current patent stay or block approval. Historical patent status may still matter in litigation records, licensing documents, or damages disputes involving conduct before expiration.

References

United States Patent and Trademark Office. (2000). U.S. Patent No. 6,133,310, Treatment of rosacea with ivermectin.
U.S. Food and Drug Administration. (2014). Soolantra (ivermectin) cream, 1%: Prescribing information. Galderma Laboratories, L.P.
35 U.S.C. § 154. Patent term.
U.S. Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations: Orange Book.
21 U.S.C. § 355(j); 35 U.S.C. § 271(e). Abbreviated new drug applications and patent certification provisions.

Details for Patent: 6,133,310

Summary for Patent: 6,133,310