DCT

1:24-cv-01011

Endocyte Inc v. Point Biopharma Global Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:

  • Case Identification: 1:24-cv-01011, S.D. Ind., 06/13/2024

  • Venue Allegations: Plaintiffs allege venue is proper in the Southern District of Indiana because Defendants have their principal places of business in the district, maintain headquarters and manufacturing facilities there, and have committed alleged acts of infringement within the district, including manufacturing and offering to sell the accused product.

  • Core Dispute: Plaintiffs allege that Defendants’ prostate-cancer-targeting radiotherapeutic drug, PNT2002, infringes a patent related to prostate-specific membrane antigen (PSMA) binding ligand-linker conjugates for delivering therapeutic agents.

  • Technical Context: The technology involves radiopharmaceutical drug conjugates designed to selectively target and deliver a radioactive payload to prostate cancer cells that overexpress the PSMA protein, a key biomarker in this type of cancer.

  • Key Procedural History: The complaint states that the patent-in-suit, assigned to Plaintiff Purdue Research Foundation, was exclusively licensed to Plaintiff Endocyte, which was later acquired by Plaintiff Novartis. Plaintiffs also allege sending letters to Defendant POINT and its commercialization partner, Lantheus, in February 2024, offering a license to the patent-in-suit prior to filing the complaint.

Case Timeline

Date Event
2007-08-17 ’970 Patent Priority Date
2020-04-21 ’970 Patent Issue Date
2022-10-18 ’970 Patent Certificate of Correction Issued
2022-11-01 POINT and Lantheus enter Commercialization Agreement
2023-09-01 Lantheus and POINT initiate expanded access program for PNT2002
2023-12-01 Eli Lilly acquires POINT
2024-01-01 PNT2002 expanded access program begins patient treatment (First Quarter)
2024-02-26 Plaintiffs send license offer letters to POINT and Lantheus
2024-03-21 Eli Lilly (POINT's parent) confirms receipt of license offer letter
2024-03-22 Lantheus confirms receipt of license offer letter
2024-06-13 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 10,624,970 - "PSMA Binding Ligand-Linker Conjugates and Methods for Using"

  • Patent Identification: U.S. Patent No. 10,624,970, "PSMA Binding Ligand-Linker Conjugates and Methods for Using," issued April 21, 2020.

The Invention Explained

  • Problem Addressed: The patent background describes the need for prostate cancer treatments that are more selective for cancerous tissue to mitigate side effects, such as osteoporosis and liver damage, associated with conventional treatments like hormonal therapy (’970 Patent, col. 1:47-56).
  • The Patented Solution: The invention is a molecular conjugate designed to target cells that overexpress Prostate Specific Membrane Antigen (PSMA). The conjugate consists of three parts: a PSMA-binding ligand that acts as a "homing device," a biologically active "payload" (such as a therapeutic or imaging agent), and a specific type of linker that connects the two, enabling targeted delivery of the payload directly to prostate cancer cells (’970 Patent, Abstract; col. 2:44-57).
  • Technical Importance: This technology provides a platform for creating targeted radiopharmaceuticals capable of delivering radiation directly to cancer cells while minimizing systemic exposure, a key strategy in modern oncology (Compl. ¶¶4, 30).

Key Claims at a Glance

  • The complaint asserts independent claims 1 and 6, and dependent claim 2 (Compl. ¶50).
  • Independent Claim 1 recites a conjugate with the following essential elements:
    • A conjugate comprising a ligand of PSMA (B), a linker (L), and a drug (D).
    • The linker is covalently bound to both the drug and the ligand.
    • The PSMA ligand (B) is a urea of two amino acids selected from a specified list (e.g., glutamic acid, lysine).
    • The linker (L) is a divalent linker of 14 to 24 atoms in length.
    • The linker (L) comprises a divalent tripeptide containing at least one optionally substituted phenylalanine (Phe) and at least one optionally substituted tyrosine (Tyr).
    • The drug (D) is a radioactive isotope of a metal coordinated to a chelating group.
  • Independent Claim 6 recites a pharmaceutical composition comprising the conjugate of claim 1 and at least one pharmaceutically acceptable carrier or excipient (Compl. ¶58).

III. The Accused Instrumentality

Product Identification

  • The accused instrumentality is PNT2002, a radiotherapeutic drug developed by POINT Biopharma (Compl. ¶1).

Functionality and Market Context

  • PNT2002 is alleged to be a molecular conjugate for treating PSMA-positive metastatic castration-resistant prostate cancer (Compl. ¶¶34, 45). The complaint provides a chemical structure diagram of the accused PNT2002 product (Compl. ¶52), which it alleges is a conjugate comprising a PSMA ligand (a urea of glutamic acid and lysine), a linker, and a drug (the radioactive isotope lutetium coordinated to a chelating group) (Compl. ¶53).
  • The complaint alleges that Defendant POINT has entered into a commercialization agreement with Lantheus for PNT2002, has offered to sell it, and has manufactured and supplied it for use in an expanded access program for patients who cannot be treated with currently available drugs or clinical trials (Compl. ¶¶9, 11, 45-46).

IV. Analysis of Infringement Allegations

’970 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A conjugate comprising a ligand of PSMA (B), a linker (L), and a drug (D) wherein the linker is covalently bound to the drug and the linker is covalently bound to the ligand... PNT2002 is alleged to be a conjugate comprising a PSMA ligand, a linker, and a drug, with the components covalently bound as shown in the provided chemical structure. ¶53 col. 2:60-63
...wherein B is a ligand of prostate specific membrane antigen (PSMA) that is a urea of two amino acids, wherein the two amino acids are independently selected from asparagine, aspartic acid, cysteine, glutamic acid, lysine...and combinations thereof... The ligand in PNT2002 is alleged to be a urea of two amino acids: glutamic acid and lysine, both of which are recited in the claim's list of permissible amino acids. ¶53 col. 45:55-67
...L is a divalent linker of 14 to 24 atoms in length, the divalent linker comprising a divalent tripeptide comprising one or more optionally substituted Phe and one or more optionally substituted Tyr... The linker in PNT2002 is alleged to be a divalent linker between 14 and 24 atoms in length and to comprise a tripeptide containing a phenylalanine (Phe) residue and a substituted tyrosine (Tyr) residue. ¶53 col. 8:36-55
...and D is a radioactive isotope of a metal coordinated to a chelating group. The drug in PNT2002 is alleged to be a radioactive isotope of the metal lutetium, which is coordinated to a chelating group. ¶53 col. 33:45-50
  • Identified Points of Contention:
    • Scope Questions: A central dispute may concern the method for calculating the linker's "length" to determine if it falls within the claimed "14 to 24 atoms" range. The precise definition of "substituted Tyr" may also become a point of contention, depending on the final confirmed structure of PNT2002.
    • Technical Questions: The infringement analysis presented in the complaint relies on a specific chemical structure for PNT2002 (Compl. ¶52). A key question for discovery will be whether the PNT2002 product as manufactured and sold by Defendants is structurally identical to the one depicted in the complaint and, by extension, to the limitations of the asserted claims.

V. Key Claim Terms for Construction

  • The Term: "a divalent linker of 14 to 24 atoms in length"

  • Context and Importance: The patentability of the invention and the allegation of infringement may depend on this specific, quantitative limitation. Practitioners may focus on this term because the method of counting the atoms in the linker's backbone is not explicitly defined in the patent, creating potential ambiguity that could either include or exclude the accused product.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The claims use the general phrase "atoms in length" without specifying a particular counting methodology, which may support an interpretation that includes all atoms in the shortest covalent path between the ligand and drug moieties (’970 Patent, col. 100:10-11).
    • Evidence for a Narrower Interpretation: The specification describes the linker as a "chain of atoms" (’970 Patent, col. 10:7-9) and provides specific examples, which may support a more constrained interpretation where only atoms in the primary backbone are counted, potentially excluding atoms in side chains or branches that are not part of the direct path.

  • The Term: "optionally substituted Tyr"

  • Context and Importance: The infringement theory hinges on the allegation that PNT2002 contains a "substituted Tyr residue" (Compl. ¶53). The permissible scope of "substituted" will be critical to determining if the accused product meets this limitation.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The plain language of the claim uses the broad term "optionally substituted" without further limitation, which suggests any chemically stable substitution on the tyrosine residue is covered (’970 Patent, col. 100:15-16).
    • Evidence for a Narrower Interpretation: The specification describes linkers containing Tyr groups and discusses particular side chain modifications and interactions, such as forming pi-pi interactions with residues in the PSMA funnel (’970 Patent, col. 8:46-55). A party could argue that these descriptions implicitly limit the term "substituted" to modifications that do not disrupt such intended functions.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement. The inducement claim is based on Defendants' alleged knowledge of the patent (from a February 2024 letter) while continuing to supply PNT2002 to their partner Lantheus pursuant to a Commercialization Agreement (Compl. ¶¶76-77). The contributory infringement claim is based on allegations that PNT2002 and its components are not staple articles of commerce and are especially made for infringing uses (Compl. ¶¶78-79).
  • Willful Infringement: The complaint alleges willful infringement based on Defendants’ alleged knowledge of the ’970 Patent since at least February 26, 2024, when Plaintiffs sent a letter offering a license. The complaint alleges that Defendants' infringing activities continued despite this knowledge (Compl. ¶¶70, 80).

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of structural identity: will discovery confirm that the chemical structure of the manufactured PNT2002 product—including its specific linker atom count and the nature of its substituted tyrosine residue—is identical to the structure alleged in the complaint and required by the asserted claims?
  • A key legal question will be one of quantitative construction: how will the court construe the term "atoms in length"? The resolution of this definitional issue will directly impact whether the PNT2002 linker, once its structure is confirmed, falls within the patent's claimed range of "14 to 24 atoms."
  • A further question will concern infringing acts: does Defendants' manufacturing of PNT2002 for an expanded access program and its contractual offers to sell the drug to a commercial partner, all prior to FDA approval, constitute acts of infringement under 35 U.S.C. § 271(a) that are not covered by the clinical trial safe harbor?