Details for Patent: 11,318,121

Which drugs does patent 11,318,121 protect, and when does it expire?

Patent 11,318,121 protects PLUVICTO and is included in one NDA.

This patent has thirty-nine patent family members in fifteen countries.

Summary for Patent: 11,318,121

Title:	PSMA binding ligand-linker conjugates and methods for using
Abstract:	Described herein are prostate specific membrane antigen (PSMA) binding conjugates that are useful for delivering therapeutic, diagnostic and imaging agents. Also described herein are pharmaceutical composition containing them and methods of using the conjugates and compositions. Also described are processes for manufacture of the conjugates and the compositions containing them.
Inventor(s):	Philip Stewart Low, Sumith A. Kularatne
Assignee:	Purdue Research Foundation
Application Number:	US17/359,314
Patent Claim Types: see list of patent claims	Use; Composition; Formulation;

Patent 11,318,121 Claim Scope and US Patent Landscape for PSMA-Targeted Radioconjugates (B–L–C Urea Linker Chelator Compounds)

United States Patent 11,318,121 covers PSMA-targeted radiolabeled chelator conjugates defined by a three-part construct (B–L–C) where B is a “urea of two amino acids” (selected from a defined amino-acid list), L is a rigid/semirigid divalent linker with specific carbonyl-bearing and arylalkyl substituted elements and strict arylalkyl side-chain limits, and C is a chelating group (including variants where a radioactive metal isotope is coordinated). Claim 1 is the core compound claim; dependent claims tighten linker architecture, covalent bonding mode (amide and carbon-nitrogen single bonds), and the presence of a coordinated radionuclide. Method-of-treatment claims cover diseases involving PSMA-expressing pathogenic cell populations using claim 4 compound or claim 21 pharmaceutical composition.

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What compounds are protected by US Patent 11,318,121 and what is the B–L–C structure in the claims?

Core formula: B–L–C with urea-based amino-acid headgroup

Claim 1 is directed to: “A compound of the formula B–L–C or a salt thereof.”

• B (urea of two amino acids): each amino acid is independently selected from:
  • asparagine, aspartic acid, cysteine, glutamic acid, lysine, glutamine, arginine, serine, ornithine, threonine.
• B is restricted by defining it as a urea formed between two of the listed amino acids (not an arbitrary urea).

Practical scope impact: An infringing compound must use a urea-based PSMA-binding “head” constrained to this specific amino-acid set, not just any urea motif.

L (divalent linker) is structurally constrained

L is “a divalent linker of between about 7 and about 20 atoms in length” and comprises all of:

1. (i) a divalent alkylene group
2. (ii) a divalent cycloalkylenecarbonyl group
3. (iii) a divalent alkylenecarbonyl group substituted with an arylalkyl side chain

Other explicit limitation:

• “provided that L has a single arylalkyl side chain.” (Claim 1)

Practical scope impact: A design-around that changes linker composition (removes a cycloalkylenecarbonyl element, changes carbonyl types, adds more than one arylalkyl side chain, or falls outside the atom-length range) is directly targeted.

C (chelator) is formula-based and provides radionuclide binding

C “comprises a chelating group of the formula wherein * represents the point of covalent attachment of the chelating group to L.”

While the chelator’s exact substructure is not reproduced in the provided claim text, the claims repeatedly tie C to coordination of a “radioactive isotope of a metal” in dependent claims (Claims 4, 8, 10, 19, 21, 24 etc.), indicating a chelator suitable for radiometal complexation.

Claim 1 excludes multi-arylalkyl linker variants

Claim 1’s “single arylalkyl side chain” is a key breadth limiter. Claim 2 and later relax some aspects (via “second divalent alkylenecarbonyl group”) but the arylalkyl constraint remains embedded in the base linker description.

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How broad is claim 1 vs dependent claims 2–16 for linker length, linker architecture, and radionuclide inclusion?

Breadth ladder

Claim 1 (base): compound B–L–C with:

• B restricted to defined amino-acid urea
• L length and component constraints, including “single arylalkyl side chain”
• C defined chelator attachment point

Claim 2: L further comprises a second divalent alkylenecarbonyl group.

• Narrows by adding a second “alkylenecarbonyl” element.

Claim 3: L is covalently bound to B through an amide bond.

• Narrows by specifying bond type connecting L to B.

Claims 4 & 8 & 10: add radionuclide presence

• Claim 4: compound includes “a radioactive isotope of a metal coordinated to the chelating group.”
• Claim 8: radionuclide + L covalently bound to B through an amide bond.
• Claim 10: radionuclide + base Claim 1 architecture (no explicit amide-to-B requirement in claim 10 itself; it’s added in later dependent claims).

Claims 6–9: specify carbon-nitrogen single bond and amide connection combinations

• Claim 6: L covalently bound to C through a carbon-nitrogen single bond.
• Claim 7: Claim 6 + L covalently bound to B via amide bond.
• Claim 8: Claim 6 + radionuclide.
• Claim 9: Claim 6 + radionuclide + L covalently bound to B via amide.

Claims 12–16: specify L–C and L–B bonding and radionuclide

• Claim 12: Claim 10 + L covalently bound to C through an amide bond.
• Claim 13: Claim 12 + L covalently bound to B via amide bond.
• Claim 14: L covalently bound to C through an amide bond (from Claim 1 base).
• Claim 15: Claim 14 + L covalently bound to B via amide bond.
• Claim 16: Claim 1 + L covalently bound to B via amide bond.

What this means for infringement design

A competitor can reduce risk by modifying at least one of:

• the urea head composition (B not in the listed amino-acid set)
• linker composition (must include the cycloalkylenecarbonyl and alkylenecarbonyl elements, and meet atom-length range)
• arylalkyl side-chain count (Claim 1 restricts to single arylalkyl side chain)
• attachment chemistries between B–L and L–C (amide vs C–N single bond vs amide)

However, because the claims stack logically, a product matching the base B–L–C may still land on intermediate dependent claims if it uses radionuclide complexation and amide/C–N bond types consistent with the ladder.

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What formulations and compositions are protected by US 11,318,121 (claims 17–28), including lyophilizates and aqueous carrier versions?

Composition claim 17 tracks the compound claim 1

Claim 17 covers a composition comprising:

• (a) the compound of formula B–L–C (or salt), with the same B and L and C restrictions as Claim 1 (including single arylalkyl side chain), plus
• (b) optionally a component selected from carriers, diluents, excipients, and combinations.

Practical scope impact: Claim 17 is broad on formulation components; it is not limited to any specific buffer or excipient category beyond typical carrier/diluent/excipient.

Lyophilizate option (claim 18)

Claim 18: composition is a reconstitutable lyophilizate.

• Narrows to lyophilized formats.

Radionuclide-bearing compositions (claims 19, 21)

Claim 19: compound further comprises radioactive isotope coordinated to chelator. Claim 20: composition is a pharmaceutical composition. Claim 21: Claim 19 + Claim 20.

Practical scope impact: Pharmaceutical formulation status is explicitly claimed; this matters for FDA regulatory and market entry disputes where the same active compound is supplied in different presentation.

Aqueous solution carrier embodiment and specific linker expansion (claim 22)

Claim 22: composition comprises a carrier that comprises an aqueous solution, and wherein:

• L further comprises a second divalent alkylenecarbonyl group, and
• L covalently bound to chelating group through a carbon-nitrogen single bond.

Additional structural composition claim hooks (claims 23–28)

• Claim 23: second divalent alkylenecarbonyl group + L–C bound via C–N single bond.
• Claim 24: Claim 19 + second alkylenecarbonyl + C–N single bond + pharmaceutical composition.
• Claims 25–28: specify covalent bond types between B–L and L–C as amide bonds (combinations).

Bottom line: The composition claims are tied to the same structural compound limitations as the method claims. Claim 21 is the centerpiece for method-of-treatment (see below).

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What medical uses are protected, and how do claims 29–30 link the patent to PSMA-expressing disease treatment?

Method claim 29 uses compound claim 4

Claim 29: method of treating disease involving PSMA-expressing pathogenic cell populations, administering a therapeutically effective amount of:

• the compound of claim 4 (radioactive isotope coordinated to chelator).

Key link: Claim 29 is limited by the radionuclide coordination requirement in claim 4.

Method claim 30 uses composition claim 21

Claim 30: same PSMA-treatment disease context, administering a therapeutically effective amount of:

• the composition of claim 21.

Claim 21 includes:

• radionuclide-coordinated compound (via claim 19)
• pharmaceutical composition status (via claim 20)

Practical scope impact: A generic/alternative supplier that markets a PSMA radioconjugate in different presentation (e.g., not a pharmaceutical composition, or lacking radionuclide coordinated to the claimed chelator, or using alternative chelator linkage chemistry) could attempt to avoid the method claims. If it still matches compound claim 4’s “radioactive metal coordinated to chelator,” method claim 29 is still a direct risk.

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How strong is the patent estate coverage for PSMA radioconjugates, based on claim architecture and typical design-around strategies?

Strength drivers

1. Strict structural definition (B, L, and C)
   The claims are not “Markush-less” broad chemical functional language; they recite concrete structural features (urea from defined amino acids; linker component composition and length; chelator attachment points).

2. Radionuclide incorporation is claimed at multiple levels
   Claims explicitly cover metal radionuclide coordination to the chelator (not merely “radiolabeled” in general).

3. Multiple attachment bond-type limitations
   Bond type between L and C (amide vs carbon-nitrogen single bond) and between L and B (amide) is repeatedly used, which restricts attempts to swap coupling chemistries without changing the overall scaffold.

4. Method claims tied to PSMA-expressing pathogenic cells
   The therapeutic claim format is aligned with radioligand oncology use cases where infringement can hinge on administration of a therapeutically effective amount.

Main design-around vectors implied by the claims

• Alter B (urea amino acids) out of the listed set
  Changing even one amino-acid identity can move a compound out of B’s defined group if the urea is no longer composed of two amino acids from the enumerated list.

• Change L linker composition
  Removing or replacing either the cycloalkylenecarbonyl group or the alkylenecarbonyl group, or changing carbonyl substitution pattern, affects literal coverage.

• Change arylalkyl side-chain multiplicity
  Claim 1 restricts L to a single arylalkyl side chain. Adding a second arylalkyl element is directly inconsistent.

• Change linkage chemistry between L and C or L and B
  If the competitor uses a different covalent linkage type than those recited (amide vs C–N single bond), they can attempt to avoid dependent claim coverage and, depending on which claim is asserted, even base coverage.

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What patent landscape issues arise when evaluating US 11,318,121 against competing PSMA radioligands?

Potential overlap categories (by claim themes)

Because the claims are framed as B–L–C conjugates with:

• a urea headgroup,
• a carbonyl-bearing linker with arylalkyl substitution,
• a chelator capable of coordinating radiometal isotopes,

the strongest competitive overlap in the broader PSMA radioligand market typically comes from molecules sharing:

• urea-based PSMA-binding motifs,
• radiometal chelators and similar linker concepts,
• comparable linker length and rigidity features.

Where litigation risk concentrates

1. If a competitor’s lead molecule uses the same headgroup amino-acid set and the same linker elements, they face high claim-mapping probability.
2. If the competitor uses radionuclide coordinated to the chelator in a pharmaceutical presentation, method claim risk grows (claims 29–30).
3. If competitors use alternative attachment chemistries to couple L to chelator or L to B, they may still infringe compound claim 1 depending on which bond types are actually required for that claim versus dependent limitations.

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Which patents and claims typically pair with 11,318,121 in filings and freedom-to-operate analyses?

Without an Orange Book or family citation list, the patent estate cannot be enumerated precisely here. However, for enforcement and FTO work, analysts typically map three adjacent layers that align with 11,318,121’s claim logic:

1. Core scaffold claims (compound formula, urea amino acids, linker components, chelator attachment chemistry)
2. Radiolabeling and chelation variants (metal radionuclide coordination to the same chelator framework)
3. Pharmaceutical presentation (lyophilizate vs aqueous carriers, plus excipient/performance specs)
4. Method-of-use (PSMA-expressing disease treatment)

Actionable reading of 11,318,121 for landscape mapping: Any family members that claim different radionuclides, alternative linker lengths within 7–20 atoms, different arylalkyl substitutions with a single arylalkyl group, or different attachment chemistries likely exist and would expand coverage around the core B–L–C motif.

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Key claim-to-risk mapping for generic entry and licensing scenarios

If a party licenses or enters with a “near” PSMA radioconjugate

Evaluate claim coverage against:

• B: headgroup urea formed from two amino acids within the enumerated list
• L: presence of (alkylene + cycloalkylenecarbonyl + alkylenecarbonyl substituted with arylalkyl side chain), plus 7–20 atoms length
• L arylalkyl count: one arylalkyl side chain
• attachment chemistry: L–B amide; L–C amide or C–N depending on the product
• radiolabel status: radioactive metal coordinated to the chelator
• formulation: pharmaceutical composition status; lyophilizate vs aqueous carrier

If a party attempts to enter with a different radionuclide

The claims do not list specific radionuclide isotopes in the provided excerpt; they require “a radioactive isotope of a metal coordinated to the chelating group.” That language can still cover broad radionuclide substitutions if the chelator coordinates the metal radionuclide.

If a party changes formulation but keeps the active

Claim 17 and claim 20 show that “pharmaceutical composition” and optional carrier/excipient inclusion are accommodated. Only moving away from the “pharmaceutical composition” presentation, or changing active compound structure so it is out of B–L–C literal scope, is likely to materially reduce infringement risk.

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Timeline and exclusivity questions: When does patent 11,318,121 lose exclusivity?

No filing date, priority date, issue date, or stated term/expiration data is provided in the prompt. Without that, a precise US expiration timeline cannot be computed or stated.

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Key Takeaways

• US 11,318,121 is a structured-scaffold patent for PSMA radioconjugates using a B–L–C construct: urea headgroup (two amino acids from a defined list), carbonyl-rich divalent linker with defined components and 7–20 atom length, and a defined chelator attachment.
• Claim 1 anchors broad compound coverage within strict constraints, including L’s single arylalkyl side chain requirement.
• Claims 2–16 narrow coverage by adding linker elements (second alkylenecarbonyl), enforcing amide vs carbon-nitrogen covalent attachment positions, and requiring radioactive metal isotope coordination to the chelator.
• Claims 17–28 extend coverage to pharmaceutical compositions, including reconstitutable lyophilizates and specified aqueous-carrier embodiments, while preserving the same B–L–C structure constraints.
• Claims 29–30 provide PSMA-focused method-of-treatment coverage tied to claim 4 (compound with coordinated radionuclide) and claim 21 (pharmaceutical composition with coordinated radionuclide).

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FAQs

1) Which part of the molecule is most important to avoid literal infringement under US 11,318,121?
The B urea amino-acid set and the L linker architecture (cycloalkylenecarbonyl + alkylenecarbonyl with a single arylalkyl side chain, within 7–20 atoms) are the main literal-scope drivers.

2) Does US 11,318,121 require a radionuclide for all claims?
No. Radionuclide coordination is required in dependent claims such as claim 4 and claim 10, and is embedded into method claims (29 uses claim 4; 30 uses claim 21), while claim 1 itself is not limited to a radionuclide.

3) Are lyophilized presentations covered?
Yes. Claim 18 covers compositions that are reconstitutable lyophilizates, assuming the underlying B–L–C active meets the claim-defined structure.

4) Can changing the linker bond chemistry avoid infringement?
Bond type is repeatedly constrained in dependent claims: L–B via an amide bond and L–C via either an amide bond or a carbon-nitrogen single bond. Changing linkage chemistry can reduce coverage if it moves the product outside the claim’s required covalent bond types relevant to asserted claims.

5) Are method-of-use claims limited to PSMA-expressing disease?
Yes. Claims 29–30 require treating diseases involving pathogenic cell populations expressing PSMA, using the specified radionuclide-coordinated compound or pharmaceutical composition.

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References

1. US Patent 11,318,121 (issued patent document; claim text provided in prompt).

Drugs Protected by US Patent 11,318,121

Applicant	Tradename	Generic Name	Dosage	NDA	Approval Date	TE	Type	RLD	RS	Patent No.	Patent Expiration	Product	Substance	Delist Req.	Patented / Exclusive Use	Submissiondate
Novartis	PLUVICTO	lutetium lu-177 vipivotide tetraxetan	SOLUTION;INTRAVENOUS	215833-001	Mar 23, 2022		RX	Yes	Yes	11,318,121		Y	Y		FOR TREATMENT OF ADULT PATIENTS WITH PROSTATE-SPECIFIC MEMBRANE ANTIGEN (PSMA)-POSITIVE METASTATIC CASTRATION-RESISTANT PROSTATE CANCER (MCRPC) WHO HAVE BEEN TREATED WITH ANDROGEN RECEPTOR PATHWAY INHIBITOR (ARPI) THERAPY

International Family Members for US Patent 11,318,121

Country	Patent Number	Estimated Expiration	Supplementary Protection Certificate	SPC Country	SPC Expiration
Australia	2008289108
Canada	2696627
China	102014956