US Patent 9,539,250: Delafloxacin Meglumine Composition Claims, Patent Scope and Generic Entry Risk

US Patent 9,539,250 protects delafloxacin meglumine compositions, including crystalline and chemically pure salt material, oral and parenteral formulations, and methods of treating bacterial infections. The patent is directed to Baxdela’s active pharmaceutical ingredient in its meglumine salt form, not to delafloxacin’s underlying quinolone molecule generally.

The broadest claims are product-by-process claims. They require delafloxacin meglumine prepared by combining delafloxacin and meglumine in a solvent, filtering the resulting solid, and drying it. Dependent claims add crystallinity, purity, excipients, dosage forms, dosing ranges, and bacterial-infection treatment.

Based on the patent’s filing chronology, the ordinary 20-year term is expected to run to approximately June 2033, subject to any patent-term adjustment, terminal disclaimer, or regulatory patent-term extension reflected in the official USPTO and FDA records. The patent is relevant to generic ANDA strategy because it covers the marketed meglumine salt and finished dosage forms, although its product-by-process structure creates potential design-around and litigation issues.

What drug and salt are protected by US Patent 9,539,250?

The protected active ingredient is delafloxacin meglumine, the meglumine salt of delafloxacin.

Delafloxacin is a fluoroquinolone antibacterial marketed by Melinta Therapeutics under the Baxdela brand. Baxdela has been approved in oral and intravenous dosage forms for certain acute bacterial skin and skin-structure infections. The patent claims identify the drug through its full chemical name rather than through the shorter term “delafloxacin.”

Element	Description
Active moiety	Delafloxacin
Salt former	Meglumine, also called N-methyl-D-glucamine
Claimed salt	Delafloxacin meglumine
Therapeutic class	Fluoroquinolone antibacterial
Covered dosage forms	Oral and parenteral compositions
Covered disease use	Bacterial infection in a fish or mammal
Commercial relevance	Baxdela tablets and injection
Patent	US 9,539,250
Grant date	January 10, 2017
Expected ordinary expiration	Approximately June 2033, subject to official term adjustments

The claims do not cover every delafloxacin salt. A product using a different counterion, such as sodium, potassium, hydrochloride, or another pharmaceutically acceptable salt, would not fall within the literal salt limitation unless another claim or patent independently covers it.

What is the scope of the independent claims?

Claims 1 and 9 are the principal composition claims. Claims 42, 45, 48, and 51 are the principal method-of-treatment claims.

Claim 1: composition claim

Claim 1 covers a composition comprising delafloxacin meglumine prepared by a three-step process:

Delafloxacin and meglumine are combined in a solvent.
The mixture is filtered to produce a solid.
The solid is dried to produce delafloxacin meglumine.

The claim has two separate dimensions:

A product limitation: the composition must contain delafloxacin meglumine.
A process limitation: the salt must be prepared through the specified combination, filtration, and drying sequence.

The claim does not expressly require an excipient, a dosage form, a particular solvent, a defined temperature, a particular drying condition, or a specific crystal polymorph. It therefore reaches relatively broadly within the class of delafloxacin meglumine made by the claimed process.

Claim 9: therapeutic composition claim

Claim 9 adds at least one excipient to the delafloxacin meglumine composition. This claim is directed more directly to pharmaceutical products, including tablets, capsules, injectable products, and other dosage forms.

The claim does not require a particular excipient identity. The excipient limitation is satisfied by the presence of at least one excipient, subject to the same product-by-process requirement.

Treatment claims

Claims 42, 45, 48, and 51 cover administering the claimed therapeutic compositions to treat bacterial infections in fish or mammals. Dependent claims narrow the subject to mammals and specify a dose of approximately 0.03 to 200 mg/kg body weight.

The treatment claims are composition-dependent. A method using delafloxacin meglumine that was not made by the process required by the incorporated composition claim presents a stronger non-infringement position than a method using the patented composition as claimed.

How do the dependent claims narrow the patent?

The 53-claim structure creates several claim clusters.

Claim cluster	Main limitation	Commercial significance
1-8	Delafloxacin meglumine made by the specified process	Core salt and manufacturing claim
2-4	Crystalline salt and at least about 95% crystalline purity	Covers crystalline API material
5-8	Chemical purity, including about 97%, 98%, or 100%	Purity-based product limitations
9-17	Therapeutic composition with excipient	Finished pharmaceutical composition
18-20	Oral, solid oral, or parenteral dosage form	Product-route coverage
21	Broad specified excipient list	Formulation coverage
22-30	Filler, binder, disintegrant, buffer, and lubricant	Tablet and solid dosage-form architecture
31-41	Oral dosage forms and specific excipients	Narrower formulation combinations
42-53	Treatment of bacterial infection in fish or mammals	Method-of-use coverage

The strongest commercial claims are likely claims 1 and 9, because they provide the broadest access to the claimed salt and finished product. Claims 22 and 38 are narrower but more closely aligned with a conventional solid oral tablet formulation.

What formulations are protected by US 9,539,250?

The patent claims a broad range of excipients and then narrows to specific formulation components.

Broad excipient claim

Claim 21 lists excipients including cellulose, povidone, crospovidone, sodium phosphate salts, citrate, magnesium stearate, lactose, starches, oils, surfactants, binders, lubricants, and buffering agents.

Because the claim uses “selected from the group consisting of,” the listed excipients define the relevant universe for that claim. A formulation using an unlisted excipient may avoid claim 21, although it could remain within claim 9 if it contains at least one excipient.

Functional excipient combination

Claim 22 requires:

At least one filler;
At least one binder;
At least one disintegrating agent;
At least one buffering agent; and
At least one lubricant.

This claim is broader than claim 38 because it defines the excipients by function rather than by a specific chemical identity.

Specific tablet formulation

Claim 38 requires:

Cellulose as filler;
Povidone as binder;
Crospovidone as disintegrant;
A sodium phosphate salt as buffer; and
Magnesium stearate as lubricant.

Claim 39 adds a citrate. Claims 40 and 41 recast substantially the same formulation architecture under the broader therapeutic-composition framework.

Formulation component	Claimed example
Filler	Cellulose
Binder	Povidone
Disintegrant	Crospovidone
Buffer	Sodium phosphate salt
Lubricant	Magnesium stearate
Optional additional buffer	Citrate

A generic tablet that uses the same active salt and the same excipient architecture would face materially higher literal-infringement risk than a formulation using a different salt, different manufacturing route, or materially different excipient system.

How important is the product-by-process language?

The product-by-process language is central to both the scope and vulnerability of the patent.

Under US law, a product-by-process claim generally requires the claimed product to have been made by the recited process for infringement purposes. The process limitation also does not necessarily save the claim from prior-art challenges. If the product itself was known or obtainable before the relevant filing date, the process wording may not prevent anticipation or obviousness arguments. Federal Circuit precedent distinguishes the role of process limitations in validity analysis from their role in infringement analysis. See SmithKline Beecham Corp. v. Apotex Corp., 403 F.3d 1331 (Fed. Cir. 2005).

For this patent, a generic manufacturer could pursue several non-infringement positions:

Make delafloxacin meglumine through a materially different process.
Use a different solvent system or crystallization sequence.
Avoid the claimed filtration step as performed in the patent.
Produce a different polymorph, amorphous form, hydrate, solvate, or particle form, if technically and legally distinct.
Use a different salt form.
Use a formulation outside the narrower excipient combinations.

The strength of these positions depends on how the claims are construed, whether the accused process in fact includes the claimed steps, and whether the resulting product is materially indistinguishable from the patented product.

What do the purity and crystallinity claims cover?

Claims 2-4 and 11-13 require a crystalline salt and at least about 95% crystalline purity. Claims 5-8 and 14-17 address chemical purity at approximately 97%, 98%, or 100%.

These limitations create evidentiary questions:

How is “crystalline purity” measured?
What analytical method distinguishes crystalline from amorphous material?
Does “about 95%” include a defined measurement tolerance?
What does “about 100% chemically pure” mean when analytical methods have detection limits?
Does the purity refer to assay, chromatographic purity, phase purity, or another parameter?

The 100% purity language is commercially attractive but technically difficult to enforce literally. Pharmaceutical products normally contain trace impurities, residual solvents, degradation products, and analytical uncertainty. A generic defendant could challenge the definiteness, enablement, written-description support, or infringement measurement of these limitations depending on the specification and prosecution history.

The 95% crystallinity threshold is more operationally useful if the patent specification identifies a validated analytical method, such as powder X-ray diffraction, thermal analysis, or quantitative phase analysis. Without a defined test, enforcement may turn on expert evidence and claim construction.

What is the expected patent expiration date?

The patent’s ordinary term is tied to the earliest effective nonprovisional or international filing date for the claimed invention, not to its grant date. The relevant term is therefore not 20 years from January 10, 2017.

Public patent records identify a 2013 filing chronology with an earlier 2012 priority claim. On that basis, the expected unadjusted expiration is approximately June 2033. The precise expiration date must be confirmed against the USPTO patent-term calculation, including any patent-term adjustment and terminal disclaimer. USPTO, 35 U.S.C. §§ 154 and 156.

Event	Approximate timing
Earliest priority	June 2012
International or nonprovisional filing	June 2013
US patent grant	January 10, 2017
Expected ordinary expiration	June 2033
Possible additional protection	Patent-term adjustment or regulatory extension, if granted

Patent 9,539,250 should be analyzed together with the delafloxacin compound patent, formulation patents, crystalline-form patents, and any later continuation or divisional patents. A generic launch date cannot be determined from this patent alone.

What is the FDA and Orange Book status of Baxdela?

Baxdela is an FDA-approved small-molecule antibacterial. Its regulatory pathway is an NDA, not a biologics license application. Generic competitors would file an ANDA and could submit Paragraph IV certifications against listed patents.

The Orange Book may list patents covering the active ingredient, composition, formulation, or method of use. Listing status can change through FDA updates, patent expiration, delisting, or court decisions. The Orange Book should be checked for the current entries associated with the relevant Baxdela NDA and dosage forms. FDA, Approved Drug Products with Therapeutic Equivalence Evaluations.

The regulatory exclusivity framework is separate from patent protection:

NCE exclusivity generally lasts five years from approval, subject to a Paragraph IV limitation during the initial period.
Three-year exclusivity may apply to certain supplemental approvals involving new clinical investigations.
Patent protection can extend beyond regulatory exclusivity.
A generic applicant can file an ANDA before patent expiry and seek approval for launch after the relevant barriers expire or are resolved.

Baxdela is not eligible for biosimilar competition because delafloxacin is a chemically synthesized small molecule. The relevant competitor pathway is the ANDA generic pathway.

Which generic entry risks exist?

The main entry scenarios are as follows.

Paragraph IV challenge

A generic applicant could certify that the patent is invalid, unenforceable, or not infringed. If the patent is listed in the Orange Book and the NDA holder receives notice, a timely infringement action can trigger a 30-month regulatory stay under the Hatch-Waxman framework, subject to statutory exceptions. 21 U.S.C. § 355(j)(5)(B)(iii).

Potential Paragraph IV grounds include:

Product-by-process limitations do not distinguish the product over prior art.
The delafloxacin meglumine salt was known or obvious.
The crystallinity or purity limitations lack adequate written-description support.
“About 100% chemically pure” is indefinite.
The claimed process lacks novelty or is obvious.
The formulation claims are obvious over standard tablet excipient systems.
The claims are not infringed because the generic uses a different process or formulation.

Paragraph III certification

A generic applicant could accept the patent and certify that it will not market until the patent expires. Under the expected ordinary term, that would place launch around mid-2033, subject to other listed patents and exclusivity.

At-risk launch

A manufacturer could launch before final resolution of patent disputes. This exposes the company to damages, injunctive relief, and possible launch-related liabilities. At-risk launch decisions would require review of every Orange Book-listed delafloxacin patent, not only US 9,539,250.

What patent landscape surrounds delafloxacin?

The relevant patent estate is broader than US 9,539,250.

Patent category	Typical subject matter	Strategic relevance
Core compound patents	Delafloxacin chemical structure and quinolone derivatives	Protect the active moiety
Salt patents	Meglumine and other pharmaceutically acceptable salts	Protect API form
Composition patents	Delafloxacin meglumine with excipients	Protect finished products
Crystalline-form patents	Polymorphs, crystalline purity, XRPD-defined forms	Limit API substitution
Process patents	Salt formation, crystallization, filtration, drying	Create manufacturing barriers
Method-of-use patents	Bacterial infections and dosing regimens	Affect label carve-outs
Manufacturing patents	Intermediate synthesis and purification	Raise CMC and supply-chain barriers

The core compound patent generally presents the greatest risk to any product containing delafloxacin, while Patent 9,539,250 is particularly relevant to delafloxacin meglumine API and finished formulations. A generic developer that designs around the composition patent may still infringe an earlier compound patent or a later crystalline-form patent.

How strong is the patent estate?

US 9,539,250 has moderate strategic strength and mixed litigation strength.

Strengths

It covers the commercially relevant meglumine salt.
It reaches both API compositions and therapeutic compositions.
It covers oral and parenteral dosage forms.
It includes broad and specific excipient claim layers.
It claims treatment methods across mammals and fish.
It may create process and analytical burdens for generic manufacturers.

Weaknesses

The independent claims are product-by-process claims.
The process limitation may support a non-infringement design-around.
Crystalline-purity and chemical-purity terms may require disputed analytical definitions.
Several formulation claims rely on conventional pharmaceutical excipients.
Treatment claims are dependent on the composition claims.
The patent does not, by itself, establish exclusivity over every delafloxacin product or every delafloxacin salt.

The estate is strongest when the reference product, generic API, and generic dosage form use the same delafloxacin meglumine manufacturing route and the claimed cellulose-povidone-crospovidone-buffer-magnesium stearate formulation.

What licensing and litigation issues affect the patent?

A complete commercial assessment should distinguish three categories:

License rights from Melinta or its successors.
Litigation settlements with ANDA applicants.
Patent ownership, security interests, or assignments affecting enforcement.

No license or settlement right is created by the patent claims themselves. A settlement could provide a generic applicant with a negotiated launch date earlier than the patent’s nominal expiration, subject to antitrust review and settlement terms. Conversely, a patent assignment or exclusive license could change the party entitled to sue.

The relevant litigation record should be checked in PACER, USPTO assignment records, FDA Orange Book updates, and any Federal Circuit decisions. The patent number alone does not establish that a Paragraph IV case has been filed, settled, dismissed, or adjudicated.

How does Patent 9,539,250 compare with a generic launch strategy?

Strategy	Main benefit	Main risk
Use delafloxacin meglumine with the same process	Simplifies CMC development	High infringement exposure
Use delafloxacin meglumine with a different process	Preserves marketed salt	Product-by-process litigation risk
Use a different salt	May avoid this patent	May alter bioavailability, stability, or approval basis
Use a different polymorph or amorphous form	May avoid crystalline claims	Solid-state and regulatory comparability risk
Use a different tablet formulation	May avoid narrow formulation claims	Bioequivalence and manufacturability risk
Wait for expiration	Avoids Paragraph IV litigation	Delays market entry
File Paragraph IV	Preserves earlier launch opportunity	Litigation cost and 30-month-stay exposure

Key Takeaways

US 9,539,250 covers delafloxacin meglumine compositions made through a specified solvent, filtration, and drying process.
The patent reaches crystalline salt, purity levels, oral dosage forms, parenteral dosage forms, excipient systems, and bacterial-infection treatment methods.
Claims 1 and 9 are the principal commercial composition claims.
Claims 22, 38, and 40 are important for conventional oral solid formulations.
The product-by-process structure creates both infringement risk and design-around opportunities.
The expected ordinary expiration is approximately June 2033, subject to USPTO term calculations.
Delafloxacin is a small molecule, so generic competition proceeds through ANDAs rather than biosimilar applications.
A generic launch analysis must include the entire Orange Book-listed delafloxacin estate, not only Patent 9,539,250.
Crystalline-purity, chemical-purity, and process limitations are likely to be central validity and infringement issues.

FAQs

Does US 9,539,250 cover delafloxacin itself?

No. The claims focus on delafloxacin meglumine compositions prepared through the claimed process. Separate patents may cover delafloxacin as a compound.

Can a generic avoid US 9,539,250 by using a different meglumine manufacturing process?

Potentially. The product-by-process language creates a possible non-infringement position if the generic product is not made through the claimed combination, filtration, and drying sequence. The validity analysis may be different because process language does not automatically distinguish a known product over prior art.

Does the patent cover Baxdela injection?

Claim 9 broadly covers a therapeutic composition with an excipient, and claim 20 expressly covers a parenteral dosage form. The scope depends on whether the injection contains the claimed delafloxacin meglumine product made by the claimed process.

Is delafloxacin eligible for biosimilar competition?

No. Delafloxacin is a chemically synthesized small molecule. Competitors would generally use the ANDA pathway for a generic version.

Can a generic use a different salt of delafloxacin?

A different salt may avoid the literal meglumine limitation of this patent. It would still require separate assessment of bioequivalence, pharmaceutical suitability, FDA approval requirements, and other delafloxacin patents.

References

Food and Drug Administration. (2024). Approved drug products with therapeutic equivalence evaluations. U.S. Department of Health and Human Services.
Food and Drug Administration. (2017). Baxdela (delafloxacin meglumine) prescribing information. U.S. Department of Health and Human Services.
SmithKline Beecham Corp. v. Apotex Corp., 403 F.3d 1331 (Fed. Cir. 2005).
U.S. Patent No. 9,539,250. (2017). Delafloxacin meglumine compositions. United States Patent and Trademark Office.
United States Code, 21 U.S.C. § 355. (2024). New drugs.
United States Code, 35 U.S.C. §§ 154, 156. (2024). Contents and term of patent; extension of patent term.

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Canada	2582954	⤷ Start Trial
Denmark	3056492	⤷ Start Trial
European Patent Office	1802607	⤷ Start Trial
>Country	>Patent Number	>Estimated Expiration	>Supplementary Protection Certificate	>SPC Country	>SPC Expiration

Details for Patent: 9,539,250

Summary for Patent: 9,539,250