US Patent 9,283,282: Scope, Claim Construction, Expiration and Leuprolide Patent Landscape

US 9,283,282 protects specific leuprolide acetate depot compositions and dual-syringe dosage forms using a telechelic PLGA polyester, N-methyl-2-pyrrolidone and lyophilized leuprolide acetate. The patent is directed to the Atrigel-type delivery platform used for Eligard products. Its strongest protection is formulation-specific: a generic leuprolide product that uses ordinary PLGA, a different core molecule, a different solvent or a pre-mixed presentation may avoid literal infringement, but could still face dependent-claim or doctrine-of-equivalents issues.

The patent was issued March 15, 2016, and is associated with Tolmar Therapeutics, Inc. The relevant commercial product is Eligard, a leuprolide acetate injectable suspension approved under NDA 021343. The patent term is generally expected to extend into the late 2020s, subject to the official USPTO term calculation, patent-term adjustment and any terminal disclaimer.

What does US Patent 9,283,282 protect?

The patent protects four linked technical elements:

Leuprolide acetate as the active pharmaceutical ingredient.
N-methyl-2-pyrrolidone, commonly abbreviated NMP, as the solvent or vehicle.
A specific polyester made from two PLGA segments connected through 1,6-hexane diol.
Particular depot presentations, including dual syringes and specified drug, polymer and solvent quantities.

The core polymer has the structure:

PLG-COO-(CH2)6-OOC-PLG

This is not a generic claim to all poly(lactide-co-glycolide), or PLGA. The claim requires two PLGA segments covalently bonded through their terminal carboxyl groups to a 1,6-hexanediol core.

Basic patent information

Item	Information
Patent	US 9,283,282 B2
Issue date	March 15, 2016
Technology	Leuprolide acetate injectable depot
Assignee associated with patent	Tolmar Therapeutics, Inc.
Product relevance	Eligard leuprolide acetate depot products
Active ingredient	Leuprolide acetate
Polymer	PLGA segments linked through 1,6-hexane diol
Solvent	N-methyl-2-pyrrolidone
Presentation	Single composition or coupled dual-syringe system
Principal therapeutic use	Prostate cancer and androgen-deprivation therapy
Expected term	Late 2020s, subject to official USPTO term calculation

The claims use the transition "comprising." That language generally permits additional ingredients, excipients, stabilizers, delivery components and manufacturing aids unless another limitation excludes them.

How is claim 1 construed?

Claim 1 is the principal composition claim. A product must contain each of the following limitations:

Claim 1 limitation	Scope
Composition	A pharmaceutical composition, not merely a polymer intermediate
Treatment suitability	Suitable for treatment of prostate cancer
Polyester	Required
NMP	Required
Leuprolide acetate	Required
Polymer architecture	Two PLGA segments bonded through terminal carboxyl groups to 1,6-hexane diol
Architecture	`PLG-COO-(CH2)6-OOC-PLG`

The claim does not expressly require a particular lactide:glycolide ratio, viscosity, dose, syringe configuration or injection volume. Those limitations appear in the dependent claims.

What does "terminal carboxyl groups" require?

The claim requires the PLGA segments to be connected through their terminal carboxyl groups to the hydroxyl groups of 1,6-hexane diol. The resulting linkage is an ester linkage. A polymer made with a different diol, a different multifunctional core, or a non-covalent physical mixture should not literally satisfy this structural limitation.

A formulation containing conventional linear PLGA may therefore fall outside claim 1 if the polymer lacks the required hexanediol-centered architecture.

Does claim 1 cover all leuprolide depot formulations?

No. Claim 1 is narrower than a general leuprolide depot claim. It requires:

leuprolide acetate rather than every leuprolide salt or analog;
NMP as a composition component;
PLGA segments;
the specific 1,6-hexane diol linkage arrangement.

A leuprolide microsphere using polycaprolactone, conventional linear PLGA, polylactic acid, a different solvent or an aqueous suspension would not necessarily infringe claim 1.

How do claims 2 and 3 narrow the polymer?

Claims 2 and 3 create progressively narrower polymer limitations.

Claim 2: lactide-to-glycolide ratio

Claim 2 requires a lactide:glycolide ratio of either:

85:15; or
75:25.

The claim is directed to the composition of claim 1. A formulation using a 50:50 PLGA ratio may remain within claim 1 but should not literally meet claim 2.

Claim 3: inherent viscosity

Claim 3 requires the polyester to have an inherent viscosity within the stated range or at one of the stated values:

approximately 0.23 to 0.31 dL/g;
approximately 0.25 dL/g; or
approximately 0.27 dL/g.

Because 0.25 and 0.27 dL/g fall within the broader 0.23-0.31 dL/g range, those recited values appear to provide narrower species limitations rather than independent alternatives of substantially different scope.

Infringement analysis would depend on the test method, solvent, temperature, polymer concentration, molecular-weight distribution and whether "about" permits measurement variation. These parameters should be established from the patent specification and prosecution record before relying on a numerical non-infringement position.

What dosage forms are protected?

Claims 4 through 18 cover dosage forms that incorporate the composition limitations of claims 1 through 3.

Dual-syringe presentation

Claims 4, 9 and 14 require:

polyester and NMP in a first syringe;
lyophilized leuprolide acetate in a second syringe;
the syringes capable of coupling;
mixing before administration.

This is a substantial limitation. A ready-to-use pre-mixed syringe, vial-based product or separate-vial system may not literally satisfy the dual-syringe claim unless the components are in the claimed syringe arrangement.

The claims focus on the functional capability of the syringes to couple and permit mixing. The claim does not appear to require a particular connector, needle, luer-lock structure or mixing sequence, unless such limitations are found elsewhere in the specification or prosecution history.

550-mg formulation

Claims 5, 10 and 15 cover a formulation in which:

polyester plus NMP totals approximately 550 mg;
polyester is 50 wt% of that combination;
leuprolide acetate weighs approximately 73-74 mg.

The polymer and NMP quantities implied by the claim are approximately 275 mg each. The leuprolide quantity is separate from the 550-mg polymer/NMP total.

0.375-mL, 45-mg formulation

Claims 6, 11 and 16 cover approximately:

Component	Amount
Total volume	0.375 mL
Leuprolide acetate	45 mg
Polyester	165 mg
NMP	165 mg

The polymer and solvent are present in approximately equal quantities.

0.5-mL, 30-mg formulation

Claims 7, 12 and 17 cover approximately:

Component	Amount
Total volume	0.5 mL
Leuprolide acetate	30 mg
Polyester	211.5 mg
NMP	258.5 mg

This formulation has a higher NMP-to-polyester ratio than the 45-mg presentation.

0.375-mL, 22.5-mg formulation

Claims 8, 13 and 18 cover approximately:

Component	Amount
Total volume	0.375 mL
Leuprolide acetate	22.5 mg
Polyester	159 mg
NMP	194 mg

This dosage form has more NMP than polyester by weight.

How are the claims organized?

The claims repeat the same dosage-form limitations across three composition tiers.

Composition base	Dual syringe	550 mg / 73-74 mg	45 mg dose	30 mg dose	22.5 mg dose
Claim 1 composition	4	5	6	7	8
Claim 2 composition	9	10	11	12	13
Claim 3 composition	14	15	16	17	18

This structure gives the patent several fallback positions. A challenger may avoid a narrow dosage claim by changing dose, volume or excipient quantity, while still confronting claim 1. Conversely, a product that does not meet the exact claim 1 polymer architecture should not be captured by the dependent claims because every dependent claim incorporates claim 1 directly or through claims 2 and 3.

How strong is the patent estate for Eligard?

The patent has meaningful but technically bounded strength.

Strongest features

The strongest enforcement points are likely:

the unusual hexanediol-linked PLGA structure;
the combination of that polymer with NMP and leuprolide acetate;
the dual-syringe configuration;
dosage forms corresponding to commercial Eligard strengths;
the combination of structural and quantitative limitations.

A generic developer using the same Atrigel-type formulation and presentation would face a high literal-infringement risk if it uses the claimed polymer architecture and NMP system.

Narrower or vulnerable features

Potential pressure points include:

whether the accused polymer actually has the claimed telechelic architecture;
whether the polymer has terminal carboxyl groups in the required configuration;
the meaning of "about" for viscosity, volume and mass;
whether a product is "suitable for treatment of prostate cancer";
whether a different syringe system is capable of the claimed coupling and mixing;
written-description and enablement support for the full scope of the composition claim;
anticipation by earlier Atrigel, PLGA or leuprolide depot disclosures.

The claims are not compositionally broad enough to control every long-acting leuprolide product. They are strongest against close copies of the commercial delivery system.

What patents protect leuprolide depot products?

Leuprolide products can be protected by several patent categories:

Patent category	Typical subject matter	Relevance to US 9,283,282
Active ingredient patents	Leuprolide compound or salt	Peripheral; leuprolide is an older peptide
Depot composition patents	Polymer, solvent and peptide combination	Directly relevant
Polymer architecture patents	PLGA structure, linker or molecular weight	Directly relevant
Dosage-form patents	Syringe, mixing system and presentation	Directly relevant
Method-of-use patents	Prostate cancer or androgen deprivation	Potentially relevant
Manufacturing patents	Polymer synthesis, lyophilization, filling and coupling	May create separate barriers
Device patents	Applicator, connector or injection system	May affect launch design
Regulatory exclusivity	NDA exclusivity and pediatric exclusivity	Separate from patent rights

The patent should therefore be analyzed as one layer of a broader Eligard estate. A freedom-to-operate review cannot rely only on the claims of US 9,283,282.

What is the Orange Book status of US 9,283,282?

The relevant regulatory product is Eligard, approved under FDA NDA 021343. Orange Book treatment of a patent depends on whether it is listed for the NDA, the applicable dosage form and the relevant reference product record.

A patent may be commercially important even when it is not the only listed patent. Orange Book relevance should be checked against:

the current FDA Orange Book entry for NDA 021343;
the listed patent number;
the patent expiration date shown by FDA;
any pediatric extension;
any delisting or expiration update;
approved strengths and dosage forms.

The patent’s claim set aligns closely with Eligard’s depot composition and presentation, making Orange Book listing commercially significant if the patent is listed for the relevant NDA and strength.

When does US 9,283,282 lose exclusivity?

The patent’s expected expiration is in the late 2020s. The exact date should be taken from the USPTO Patent Examination Data System or the current FDA Orange Book entry because the legal term depends on:

the earliest effective nonprovisional filing date;
any patent-term adjustment;
any terminal disclaimer;
any patent-term extension;
statutory changes affecting the patent family.

Patent expiry is separate from FDA regulatory exclusivity. A patent may expire after NDA exclusivity has ended, and an FDA-approved generic may still face other unexpired patents.

The principal commercial conclusion is that the patent is a late-2020s barrier rather than an early-2020s barrier, assuming no invalidation, disclaimer, or other term event changes the official expiration date.

What Paragraph IV challenge risks exist?

A Paragraph IV filer could challenge the patent on several grounds.

Anticipation

The challenger would search earlier disclosures for the combined presence of:

leuprolide acetate;
NMP;
PLGA;
a hexane-diol-centered two-segment polyester;
the claimed ratios or viscosity;
the claimed dosage forms.

A reference that discloses leuprolide and PLGA generally may not anticipate the claim unless it discloses the specific polymer architecture required by claim 1.

Obviousness

Obviousness is likely to be the more important challenge. A challenger could combine:

prior PLGA-NMP depot technology;
leuprolide acetate depot disclosures;
known Atrigel or in situ implant systems;
known diol-linked or multi-arm PLGA polymers;
commercial dose and syringe presentations.

The patent holder would rely on the particular release profile, polymer behavior, syringe workflow, stability and manufacturability of the claimed combination.

Indefiniteness

The following terms may receive scrutiny:

"about";
"suitable for treatment of prostate cancer";
"inherent viscosity";
"capable of coupling";
"enable mixing."

Indefiniteness risk depends on the specification and prosecution history. The numerical limitations are more vulnerable if the patent does not specify a reproducible test method or acceptable measurement tolerance.

Written description and enablement

The challenger may argue that the patent does not adequately support the full range of:

PLGA segment compositions;
polymer viscosities;
dose levels;
volumes;
syringe configurations;
release characteristics.

The repeated dependent claims provide narrower positions, which can improve litigation resilience if the broader composition claim is challenged.

Which companies are most likely to challenge the patent?

The relevant competitive group includes companies with experience in long-acting injectable products, peptide generics and depot formulations. Potential participants include:

generic injectable manufacturers;
companies with leuprolide acetate products;
developers of PLGA microspheres or in situ depots;
firms pursuing 505(b)(2) products;
manufacturers of oncology and urology injectables.

A direct generic copy would face greater risk than a redesigned product using a different polymer architecture or delivery vehicle. A 505(b)(2) applicant could pursue a different formulation, dose presentation or administration system while relying partly on existing leuprolide safety and efficacy information.

No conclusion about a specific company’s Paragraph IV filing or litigation position should be drawn solely from the claim text. Those facts require review of FDA ANDA records, district-court dockets, PTAB filings and current Orange Book data.

What generic launch scenarios exist?

Scenario 1: Same polymer and same dual-syringe system

This is the highest-risk path. A product using the claimed hexanediol-linked PLGA, NMP and lyophilized leuprolide in coupled syringes could meet claims 1 and 4, and potentially claims 9 or 14.

Scenario 2: Same active but conventional linear PLGA

This may avoid the specific polymer-architecture limitation, although other patent families could still apply. The developer would need analytical evidence showing that the polymer is not the claimed two-segment hexanediol-linked structure.

Scenario 3: Different solvent

Replacing NMP could avoid claim 1, because NMP is expressly required. The alternative solvent would need to maintain polymer solubility, peptide stability, injection behavior and in situ depot formation.

Scenario 4: Pre-mixed presentation

A ready-to-use suspension could avoid the dual-syringe claims, but it would not necessarily avoid claim 1 if the composition contains the claimed polymer, NMP and leuprolide acetate.

Scenario 5: Different dosage strength

Changing the amount or volume may avoid claims 5 through 8, but not necessarily claim 1. The composition claim has no express dose limitation.

Scenario 6: Alternative long-acting technology

Microspheres, implants, nanoparticles, biodegradable rods or other delivery systems may avoid this patent if they do not use the claimed polymer-solvent combination. Separate formulation, manufacturing and method-of-use patents would remain relevant.

What manufacturing and intellectual-property barriers remain?

The principal manufacturing barrier is reproducing the required polymer architecture with consistent:

lactide:glycolide ratio;
inherent viscosity;
terminal functional groups;
molecular-weight distribution;
residual solvent profile;
degradation and release behavior.

The dual-syringe presentation creates separate operational requirements involving:

sterile filling;
lyophilized peptide handling;
syringe coupling;
component compatibility;
reconstitution or mixing time;
injection-force specifications;
container-closure integrity.

Regulatory comparability may also be difficult even if a product avoids literal infringement. Long-acting injectable products are sensitive to polymer molecular weight, particle or phase morphology, residual NMP, release kinetics and injection performance. These variables can create development barriers independent of the patent claims.

How does this patent compare with conventional leuprolide products?

Attribute	Claimed US 9,283,282 system	Conventional leuprolide injection
Active	Leuprolide acetate	Leuprolide acetate or another leuprolide formulation
Polymer	Hexanediol-linked PLGA segments	May use no polymer or a different PLGA structure
Solvent	NMP required	May use another vehicle
Release mechanism	In situ biodegradable depot	Could be microsphere, implant or solution
Presentation	Dual syringe expressly claimed in several claims	May be vial, prefilled syringe or other system
Dose protection	Specific 22.5-, 30-, 45-mg and 73-74-mg embodiments	Depends on product
Primary risk	Close Atrigel-type copy	Lower risk if technology is materially different

Key Takeaways

US 9,283,282 is a formulation and dosage-form patent, not a broad patent on leuprolide.
Claim 1 requires the specific PLG-COO-(CH2)6-OOC-PLG polymer architecture, NMP and leuprolide acetate.
Claims 2 and 3 narrow the polymer by lactide:glycolide ratio and inherent viscosity.
Claims 4-18 cover dual-syringe systems and specific commercial dosage configurations.
A close copy of the Eligard Atrigel system presents the highest infringement risk.
A conventional linear PLGA product, different solvent, alternative presentation or different depot technology may avoid literal infringement of this patent.
The patent is associated with Tolmar’s Eligard product and is expected to remain commercially relevant into the late 2020s.
Orange Book listing, current expiration, terminal-disclaimer status and any Paragraph IV litigation must be confirmed against current FDA, USPTO and court records.
The most material invalidity issues are obviousness, polymer-structure disclosure, numerical claim construction and enablement.
Patent expiry alone does not eliminate other formulation, manufacturing, device or method-of-use barriers.

FAQs

Does US 9,283,282 cover leuprolide acetate generally?

No. It covers leuprolide acetate only in a composition containing NMP and the claimed hexanediol-linked PLGA polyester.

Can a generic avoid the patent by changing only the leuprolide dose?

Changing the dose may avoid claims 5 through 8, but it will not necessarily avoid claim 1, which does not specify a dose.

Does using ordinary PLGA avoid US 9,283,282?

It may. Ordinary linear PLGA does not necessarily have the claimed two-segment structure covalently linked through 1,6-hexane diol. Analytical polymer characterization would be required.

Are the dual-syringe claims broader than the composition claim?

No. The dual-syringe claims depend on the composition claims. They add presentation and mixing limitations but retain the underlying polymer, NMP and leuprolide requirements.

Is a 505(b)(2) product automatically free of this patent?

No. The regulatory pathway does not determine patent infringement. A 505(b)(2) product using the claimed composition or polymer architecture could still face the patent.

References

United States Patent and Trademark Office. (2016). U.S. Patent No. 9,283,282, Leuprolide acetate depot formulations.
U.S. Food and Drug Administration. (n.d.). Drugs@FDA: Eligard, NDA 021343.
U.S. Food and Drug Administration. (n.d.). Approved drug products with therapeutic equivalence evaluations.
United States Code. (2012). 35 U.S.C. §§ 154, 156.
United States Code. (2012). 21 U.S.C. § 355(j).

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Austria	259217	⤷ Start Trial
Austria	296088	⤷ Start Trial
Austria	458469	⤷ Start Trial
Australia	1331200	⤷ Start Trial
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Summary for Patent: 9,283,282