Patent: 10,105,354

Summary for Patent: 10,105,354

Title:	Inhibition of crystal growth of roflumilast
Abstract:	Roflumilast crystals have been shown to increase in size during storage. The size of the roflumilast crystals can affect the bioavailability and efficacy of a pharmaceutical composition. The growth of roflumilast crystals can be inhibited during storage by including hexylene glycol in the composition. The resulting composition has improved bioavailability and efficacy and can be used to inhibit phosphodiesterase 4 in a patient in need of such treatment.
Inventor(s):	Osborne; David W. (Fort Collins, CO)
Assignee:	Arcutis, Inc. (Menlo Park, CA)
Application Number:	15/848,505
Patent Claims:	see list of patent claims

United States Patent 10,105,354 (US10105354): Claim-By-Claim Validity and US Landscape Risk

US 10,105,354 is drafted as a topical, PDE4-inhibition method that combines roflumilast with at least one additional active agent, places the additional agent in a microparticulate pharmaceutical form, and uses hexylene glycol in the composition. The independent claim is structurally anchored on four elements that drive enforceability and obviousness: (i) PDE4 inhibition in a patient, (ii) roflumilast as one active agent, (iii) at least one additional agent as a microparticulate pharmaceutical dispersed in the formulation, and (iv) hexylene glycol as a formulation ingredient.

This analysis focuses on whether those elements are likely to be meaningfully differentiating over prior art, how broadly the claim reads, where the claim is vulnerable on claim construction and written description/enablement, and what the most relevant competitive landscape vectors look like for freedom-to-operate (FTO).

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What is the core inventive structure of Claim 1?

Claim 1 elements (independent claim)

Claim 1 recites a “method for inhibiting phosphodiesterase 4” by topical-style administration (made more explicit in dependent claims) through a composition with:

1. Hexylene glycol in the administered composition.
2. At least two active agents in combination, one of which is roflumilast.
3. Roflumilast is one of the active agents that is dissolved in the composition.
4. At least one other active agent is a microparticulate pharmaceutical dispersed in the composition.
5. The method is “in a patient in need thereof” with implied therapeutic targeting of PDE4-mediated disease states (made explicit in dependent claims).

What the claim covers in functional terms

The claim does not confine:

• disease type in Claim 1 (it is later restricted in dependent claims),
• formulation vehicle beyond hexylene glycol and general “composition,”
• the microparticulate definition (no size range, no polymer, no release kinetics, no surface treatment),
• whether the microparticles are drug-only or drug-in-carrier.

That breadth matters: it converts what may be a narrow formulation observation into a wide method covering any topical PDE4 inhibition achieved with roflumilast + hexylene glycol + a second active agent provided as microparticles.

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How enforceable are the “micro-particulate” and “dissolved roflumilast” limitations?

Micro-particulate pharmaceutical: high uncertainty, high breadth

The claims use “microparticulate pharmaceutical” repeatedly but provide no measurable definition. In practice, such terms invite broad interpretation unless the spec nails down particle size distributions and material composition.

Enforceability impact

• If “microparticulate” is construed broadly (e.g., any suspension/dispersed solid in micron range without a clear cutoff), the limitation becomes easier to meet for many existing topical suspensions or microsphere formulations.
• If “microparticulate” is construed narrowly, then enforceability depends entirely on the patent’s disclosure and prosecution history consistency.

Validity impact

• Even if the term is construed narrowly, the concept of microparticulate delivery for topical actives is a well-established formulation technology. The differentiator is not “microparticles,” it is the combination of roflumilast + hexylene glycol + microparticulate second active for PDE4 inhibition.

Roflumilast dissolved: a design-around lever

Claim 1 requires roflumilast to be “dissolved in the composition.” This creates a potential workaround:

• convert roflumilast from “dissolved” to “dispersed/particulate” (e.g., amorphous dispersion, micronized suspension, solid dispersion) and argue the dissolution limitation is not met.

However, in infringement, the “dissolved” requirement usually turns into:

• what fraction is dissolved vs suspended at dosing,
• whether transient equilibrium counts,
• and whether analytical methods define “dissolved” (solubility limits).

A formulation that contains some roflumilast in solution and some as particles can still arguably satisfy “dissolved,” because the claim does not require 100% solubilization.

Validity impact

• Prior art topical roflumilast work (if it uses solubilizing excipients) can make “dissolved roflumilast” non-distinct.

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What does hexylene glycol contribute to novelty and non-obviousness?

Hexylene glycol is a formulation ingredient used widely as a humectant/preservative and skin-conditioning agent. In claim structure, it is a required component. That helps novelty only if:

1. hexylene glycol is used in an unconventional way for this specific therapeutic intent, or
2. prior art uses different preservatives/humectants or lacks hexylene glycol in comparable roflumilast PDE4 compositions, or
3. hexylene glycol enables unexpected properties such as PDE4 inhibition efficacy via enhanced skin penetration of roflumilast or improved delivery of both dissolved roflumilast and microparticulate actives.

Critical lens Most validity challenges will treat hexylene glycol as:

• a routine excipient unless the patent provides evidence of a non-routine effect tied to PDE4 inhibition or synergistic performance with microparticles.
• a common ingredient in topical dermatology formulations, increasing obviousness risk when paired with a routine topical PDE4 inhibitor strategy.

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How limiting are the dependent claims on disease scope (Claims 11-14)?

Claim 11: disease categories

Claim 11 expands the therapeutic scope to:

• acute and chronic airway disorders,
• proliferative, inflammatory and allergic dermatoses,
• disorders based on excessive TNF and leukotrienes,
• heart disorders treated by PDE inhibitors,
• GI or CNS inflammations,
• eye disorders,
• arthritic disorders,
• disorders treatable via tissue-relaxant action of PDE inhibitors.

This is broad across many therapeutic areas where PDE4 inhibitors are already conceptually positioned.

Claim 12: specific dermatoses list

Claim 12 narrows the dermatoses set to:

• psoriasis (vulgaris),
• eczema,
• acne,
• Lichen simplex,
• sunburn,
• pruritus,
• alopecia areata,
• hypertrophic scars,
• discoid lupus erythematosus,
• pyodermias.

This list has high breadth but is still constrained to topical dermatology-adjacent conditions.

Claims 13-14: acne and the nature of the second active

• Claim 13: acne + additional active is an antibiotic.
• Claim 14: acne + additional active is a corticosteroid.

These dependent claims are not likely to be “narrow enough” if the independent claim remains broad, but they can matter for prosecution history estoppel or for post-grant narrowing strategies by the patentee.

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What is the additional-active list in Claim 4 doing to the patent’s strength?

Claim 4 identifies a large catalog of possible additional agents spanning:

• small-molecule anti-inflammatories and immunomodulators (methotrexate, azathioprine, 6-thioguanine),
• keratolytics/anti-proliferatives (anthralin, salicylic acid, urea),
• photosensitizers/antimetabolites (methoxsalen, 5-fluorouracil, propylthouracil),
• immunosuppressants (tacrolimus, mycophenolate mofetil, cyclosporine),
• biologics (adalimumab, ustekinumab, infliximab),
• PDE-adjacent symptom agents (bronchodilators),
• broad anti-infectives (antibiotics referenced later indirectly via Claim 13),
• and corticosteroids are also explicitly enumerated.

Critical implication This list increases claim breadth and can inflate obviousness risk because:

• formulation combinations of anti-inflammatory/immune-modulating agents with PDE inhibitors are predictable therapeutic pairings in dermatology/inflammation.
• microparticulate delivery for topical agents is widely known.

Unless the patent’s specification provides support for each additional agent being usable in microparticulate form within the roflumilast + hexylene glycol system, written description and enablement become a vulnerability vector. While you asked for claims and landscape, the breadth of Claim 4 is itself a red flag for a formulation patent.

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How broad is the formulation coverage in Claims 5-10?

Claim 5: topical dosage forms

Claims 5 covers topical forms including:

• aerosols, foams, sprays,
• emulsions, gels, liquids, ointments, pastes,
• shampoos, suspensions,
• and “systems.”

This is a classic breadth escalator: any topical system that includes the active combination potentially falls in-scope.

Claim 6: subtypes

Claim 6 expands to:

• oil-in-water emulsion,
• thickened aqueous gel,
• thickened hydroalcoholic gel,
• hydrophilic gel,
• hydrophilic or hydrophobic ointment.

Claim 7-8: permeation-modifying solvent selection

Claim 7 adds that the composition can include a solvent modifying skin permeation, and Claim 8 lists many common solvents/permeation enhancers:

• acetone, ethanol, benzyl alcohol,
• dimethyl sulfoxide,
• N-methyl pyrrolidinone,
• polyethylene glycol, glycerol, propylene glycol,
• isopropyl myristate, isopropyl isostearate, isopropyl palmitate variants (via esters),
• and several SD alcohol-type mixtures.

Claim 9-10: surfactant list

Claim 9 allows a surfactant; Claim 10 lists an extensive inventory of surfactants including:

• quaternary ammonium (benzalkonium chloride),
• polysorbates,
• poloxamers (poloxamer 124/181/182/188/237/407),
• ceteareth series,
• PEG stearates,
• and numerous amphoteric/anionic surfactants.

Critical implication These lists are typical of formulation patents that survive on the “combination” hook. But they also increase obviousness because the formulation toolset is essentially unrestricted. If prior art already discloses topical roflumilast formulations with conventional solvents/surfactants, Claim 5-10 do not add meaningful novelty.

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What does this mean for novelty in view of the most likely prior art categories?

Without embedding speculative references, the landscape risk is best framed by what prior art must look like to knock out novelty or obviousness:

1) Topical PDE4 inhibition with roflumilast

If any earlier US disclosure:

• uses roflumilast in a topical dermatology formulation,
• includes hexylene glycol or another common preservative/humectant,
• and discloses delivery via emulsions/gels/sprays, then Claim 1 risks a “routine combination” finding unless the patent shows a unique role for microparticles + hexylene glycol + dissolved roflumilast.

2) Microparticulate topical delivery systems

If microparticles are used to deliver anti-inflammatory, immunosuppressive, antimicrobial, or keratolytic actives in topical systems, then the novelty is not “microparticles.” It is tying microparticles to the specific roflumilast PDE4 inhibition + hexylene glycol combination.

3) Hexylene glycol in topical formulations

If hexylene glycol is already taught as a preservative/humectant in topical dermatology compositions, then it rarely contributes to non-obviousness unless the patent ties it to a measured, unexpected effect relevant to roflumilast delivery or PDE4 inhibition performance.

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What landscape dynamics matter most for FTO and design-arounds?

Design-around pathways suggested by the claim language

1. Remove hexylene glycol from the formulation.

   • Hexylene glycol is required in Claim 1. Eliminating it avoids a literal infringement path.

2. Change the second active’s physical state from “microparticulate pharmaceutical” to a different presentation not meeting the claim’s construction.

   • If the claim requires microparticles specifically in the dispersed form, using soluble forms, nanoparticles below a definition cutoff (if any exists), or molecularly dissolved blends can reduce risk.

3. Avoid “dissolved roflumilast.”

   • Provide roflumilast predominantly as a suspension or a solid dispersion not meeting “dissolved” characterization.

4. Keep the therapeutic intent outside “PDE4 inhibition in a patient.”

   • Practically, PDE4 inhibition is pharmacological; if the product causes PDE4 inhibition, intent is less useful. Still, claims are written as methods of inhibiting PDE4; the factual pharmacology matters.

Competitive positioning risk

• Dermatology combinations often use multiple actives in topical vehicles. This claim is drafted to catch a wide array of combination partners (Claim 4), which increases “accidental infringement” risk for combination products.
• If a competitor already uses microparticulate actives and roflumilast topical delivery is on the market, then the remaining differentiator becomes hexylene glycol. That shifts litigation focus to ingredient presence and particle-state characterization.

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Are the dependent claims likely to be more defensible than Claim 1?

In many US disputes, independent claim breadth drives invalidity exposure. Here, dependent claims are not narrow in a way that resolves the core breadth problems:

• Claim 2 and Claim 3 still rely on microparticulate state, with Claim 2 adding a restriction that microparticles do not cross the stratum corneum in microparticulate state. Without a quantitative size/penetration test definition, this can remain hard to administer and easy to contest.
• Claims 5-10 remain broadly worded vehicle and excipient selections.
• Claims 11-12 restrict disease categories but still cover large clinical umbrellas where prior art PDE inhibitors and roflumilast topical strategies are plausible.

Dependent claims may help in claim construction or in narrowing during prosecution, but for validity, they still hinge on the same combination logic: roflumilast + hexylene glycol + microparticulate second active.

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Key Takeaways

• Claim 1 is built on a combination hook: PDE4 inhibition + roflumilast + hexylene glycol + a second microparticulate active with roflumilast dissolved. Enforceability turns on claim construction of “microparticulate” and the evidentiary meaning of “dissolved.”
• Breadth drives vulnerability: Claim 4’s extensive list of potential second actives plus broad topical form coverage (Claims 5-10) increases obviousness risk and can create written-description and enablement pressure points.
• Hexylene glycol is the principal formulation differentiator. If prior art already uses roflumilast topical delivery and microparticulate actives with standard excipients, novelty/non-obviousness likely rests on proving a non-routine effect from hexylene glycol in the specific roflumilast-PDE4 context.
• FTO risk is most sensitive to three variables: presence of hexylene glycol, characterization of the second active as microparticulate, and roflumilast dissolution state. These create the most direct literal design-around paths.

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FAQs

1) What is the single most important literal limitation to evaluate for infringement?

Hexylene glycol is required in Claim 1. Excluding it is the most direct route to avoid literal coverage.

2) Does the patent require a specific microparticle size or polymer carrier?

The claim text you provided does not specify particle size, carrier composition, or release characteristics, making “microparticulate” construction a central dispute point.

3) Can roflumilast be present partially dissolved and partially dispersed?

Claim 1 requires roflumilast is dissolved in the composition. A formulation with some dissolved fraction can still be argued to meet the “dissolved” requirement depending on claim interpretation and testing.

4) Do the dependent claims narrow the patent meaningfully enough to reduce risk?

They restrict disease categories and topical forms, but they keep the same core combination logic (roflumilast + hexylene glycol + microparticulate additional active), so they often do not remove the primary validity and infringement pressure points.

5) What are the most plausible design-around strategies?

Remove hexylene glycol, change the second active’s physical state away from “microparticulate,” or adjust roflumilast presentation so it is not “dissolved” as characterized by testing and construction.

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References

[1] Claims of United States Patent 10,105,354 as provided in the prompt.

Details for Patent 10,105,354

Applicant	Tradename	Biologic Ingredient	Dosage Form	BLA	Approval Date	Patent No.	Expiredate
Janssen Biotech, Inc.	REMICADE	infliximab	For Injection	103772	August 24, 1998		2037-12-20
Abbvie Inc.	HUMIRA	adalimumab	Injection	125057	December 31, 2002		2037-12-20
Abbvie Inc.	HUMIRA	adalimumab	Injection	125057	February 21, 2008		2037-12-20
Abbvie Inc.	HUMIRA	adalimumab	Injection	125057	April 24, 2013		2037-12-20
Abbvie Inc.	HUMIRA	adalimumab	Injection	125057	September 23, 2014		2037-12-20