Mesoblast Intl SARL v. Capricor Therap Inc

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Mesoblast International Sàrl (Switzerland)
  • Defendant: Capricor Therapeutics, Inc. (Delaware); Capricor, Inc. (Delaware)
  • Plaintiff's Counsel: Farnan LLP
• Case Identification: Mesoblast International Sàrl v. Capricor Therapeutics, Inc., 1:26-cv-00867, D. Del., 07/16/2026
• Venue Allegations: Venue is alleged to be proper as both Defendants are Delaware corporations and therefore reside in the District of Delaware.
• Core Dispute: Plaintiff alleges that Defendant's cardiosphere-derived cell therapy product, Deramiocel (CAP-1002), developed for the treatment of Duchenne muscular dystrophy, infringes three patents related to mesenchymal stem cell compositions and preparations.
• Technical Context: The lawsuit concerns allogeneic cellular medicines, specifically mesenchymal stem cell (MSC) therapies, a field focused on using cells from a donor to treat diseases in a recipient.
• Key Procedural History: The complaint is filed in anticipation of Defendant's potential commercial launch of Deramiocel, which is currently under FDA review with a Prescription Drug User Fee Act (PDUFA) target action date of August 22, 2026. Plaintiff notes its own MSC product, RYONCIL®, received FDA approval in December 2024 for a different indication and recently received clearance to proceed to a clinical trial for Duchenne muscular dystrophy, the same indication targeted by Defendant's product.

Case Timeline

Date	Event
2008-08-14	'004 Patent Priority Date
2010-10-08	'560 Patent Priority Date
2014-01-28	'004 Patent Issue Date
2014-06-10	'722 Patent Priority Date
2022-01-25	Capricor announces partnership with Nippon Shinyaku
2023-07-25	'560 Patent Issue Date
2024-12-18	Plaintiff's RYONCIL® product receives FDA approval
2026-04-10	Plaintiff receives FDA clearance for RYONCIL® clinical trial in DMD
2026-05-05	'722 Patent Issue Date
2026-05-12	Defendant announces FDA acceptance of BLA resubmission for Deramiocel
2026-05-28	Defendant announces expansion of commercial leadership team
2026-06-30	Defendant posts job openings related to commercial launch
2026-07-16	Complaint Filing Date
2026-08-22	PDUFA target action date for Defendant's Deramiocel

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

U.S. Patent No. 8,637,004 - "Purified mesenchymal stem cell compositions and methods of purifying mesenchymal stem cell compositions"

The Invention Explained

• Problem Addressed: The patent's background section describes the challenge that unpurified mesenchymal stem cell (MSC) compositions can contain residual immunogenic substances from the culture process (e.g., fetal bovine serum) and undesirable cell aggregates, which can cause adverse clinical reactions and reduce therapeutic efficacy (U.S. Patent 8,637,004, col. 1:40-2:3).
• The Patented Solution: The invention provides a pharmaceutically acceptable composition of purified MSCs that addresses this problem by, in part, controlling the size distribution of cell aggregates. The patent teaches that by ensuring the diameter of 90% or more of the aggregates (D90) is less than a certain size (e.g., 150 µm), the composition exhibits reduced aggregation and improved safety profiles for therapeutic use '004 Patent, abstract '004 Patent, col. 4:18-25
• Technical Importance: This approach provided a method for creating more consistent and safer clinical-grade MSC therapies by reducing immunogenicity and the risk of embolism associated with large cell clumps.

Key Claims at a Glance

• The complaint asserts at least independent claim 1 Compl. ¶34
• Claim 1 of the '004 Patent requires:
  • A pharmaceutically acceptable composition comprising purified mesenchymal stem cells,
  • wherein the composition comprises one or more mesenchymal stem cell aggregates and
  • wherein the diameter which is greater than 90% or more of said aggregates (D90) is less than about 150 µm.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 11,708,560 - "Enhanced MSC preparations"

The Invention Explained

• Problem Addressed: The patent's background highlights the heterogeneity of MSC preparations, which can vary in therapeutic effect, potency, and differentiation capacity due to factors like donor variability and manufacturing conditions. This lack of uniformity poses a significant obstacle to developing reliable, clinical-scale cell therapies '560 Patent, col. 1:47 - col. 2:38
• The Patented Solution: The invention defines a specific, uniform MSC preparation that maintains a stable phenotype and reproducible therapeutic action. It claims a large-scale preparation (at least 1 billion cells) expanded from a cryopreserved intermediate that meets a defined antigen profile (specific percentages of CD45+, CD105+, and CD166+ cells) and a specific functional activity profile (the ability to inhibit IL2Rα expression) '560 Patent, abstract '560 Patent, claim 1
• Technical Importance: This invention establishes a quality control standard for the industrial-scale manufacturing of MSCs, enabling the production of uniform, potent, and stable cell therapy batches.

Key Claims at a Glance

• The complaint asserts at least independent claim 1 Compl. ¶44
• Claim 1 of the '560 Patent requires:
  • A mesenchymal stem cell (MSC) preparation comprising:
  • a. at least 1 billion cultured human MSCs expanded from a cryopreserved in-process intermediate MSC preparation; and
  • b. an antigen and activity profile comprising:
    • i. less than 0.75% CD45+ cells;
    • ii. at least 95% CD105+ cells;
    • iii. at least 95% CD166+ cells; and
    • iv. capable of inhibiting IL2Rα expression by CD3/CD28-activated PBMCs by at least 30% relative to a control.
• The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 12,616,722 - "Treatment of immune disorders"

Technology Synopsis

The patent addresses the need for stem cell compositions that can treat immune disorders. It describes culture processes for producing genetically unmodified stem cells that express desirable levels of angiopoietin-1 (Ang-1) and a specific, defined range of Vascular Endothelial Growth Factor (VEGF), without requiring genetic modification of the cells '722 Patent, col. 2:7-11 Compl. ¶14

Asserted Claims

The complaint asserts at least independent claim 1 Compl. ¶54

Accused Features

The complaint alleges that Deramiocel comprises genetically unmodified stem cells that express both Ang-1 and VEGF within the ranges claimed by the '722 Patent Compl. ¶20 Compl. Ex. 4C

III. The Accused Instrumentality

Product Identification

• The accused product is "Deramiocel," also known as "CAP-1002" Compl. ¶1

Functionality and Market Context

• Deramiocel is a cardiosphere-derived cell (CDC) therapy developed for the treatment of Duchenne muscular dystrophy (DMD) Compl. ¶1 Compl. ¶18 The complaint alleges that CDCs are an "endogenous population of stromal cells derived from cells of transplant-qualified human hearts" and that the CDC population in Deramiocel is heterogeneous and contains MSCs Compl. ¶18 Compl. ¶19 Plaintiff alleges that Defendant is preparing for a commercial launch of Deramiocel pending FDA approval, with a PDUFA target date of August 22, 2026 Compl. ¶¶21-22 The complaint points to Defendant's public statements, expansion of its commercial team, and manufacturing preparations as evidence of imminent commercial activity Compl. ¶¶23-26 As part of its infringement allegations, the complaint includes a table from a Capricor patent showing the expression levels of various markers in its CDC lines, which Plaintiff uses to support its claim that the CDCs meet the criteria for MSCs Compl. Ex. 4A, p. 3

IV. Analysis of Infringement Allegations

'004 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
A pharmaceutically acceptable composition comprising purified mesenchymal stem cells,	Deramiocel is a purified, pharmaceutically acceptable cell composition. The complaint alleges that the cardiosphere-derived cells (CDCs) that comprise Deramiocel are a population of mesenchymal stem cells, citing flow cytometry data from a Capricor publication.	¶¶19-20; Ex. 4A	col. 4:18-25
wherein the composition comprises one or more mesenchymal stem cell aggregates and	Capricor's manufacturing process for Deramiocel allegedly forms multicellular "cardiospheres," which the complaint asserts are mesenchymal stem cell aggregates. The complaint also points to Capricor's own patent disclosures addressing cell clumping.	¶20; Ex. 4A	col. 8:20-25
wherein the diameter which is greater than 90% or more of said aggregates (D90) is less than about 150 µm.	The manufacturing process for Deramiocel is alleged to use methods that remove particles greater than about 150 µm, such as filtration, resulting in a final product where greater than 90% of aggregates are smaller than 150 µm.	¶20; Ex. 4A	col. 8:31-34

• Identified Points of Contention:
  • Scope Question: A primary issue may be whether the "cardiospheres" purposefully grown during Deramiocel's manufacturing process are equivalent to the "mesenchymal stem cell aggregates" recited in the '004 Patent, which the patent specification appears to characterize as undesirable byproducts of cell culture.
  • Technical Question: The complaint's evidence for the size limitation (D90 < 150 µm) appears to be inferred from manufacturing process steps like filtration. The case may require direct evidence of the particle size distribution in the final Deramiocel product to resolve this factual question.

'560 Patent Infringement Allegations

Claim Element (from Independent Claim 1)	Alleged Infringing Functionality	Complaint Citation	Patent Citation
at least 1 billion cultured human MSCs expanded from a cryopreserved in-process intermediate MSC preparation; and	The complaint alleges that Deramiocel is expanded from a cryopreserved "EDC master cell bank" to produce multiple therapeutic doses, which in aggregate constitute at least 1 billion cells.	¶20; Ex. 4B	col. 4:4-8
an antigen and activity profile comprising: i. less than 0.75% CD45+ cells;	Plaintiff cites Capricor's public data showing Deramiocel preparations have regional CD45 values of 0.6-0.9% and an average of 0.8±0.1%. It alleges these values meet the limitation "literally and/or under the doctrine of equivalents."	¶20; Ex. 4B	col. 7:1-3
ii. at least 95% CD105+ cells;	Plaintiff cites Capricor's data showing an average CD105 expression of 99.52% in its CDC preparations.	¶20; Ex. 4B	col. 7:3-4
iii. at least 95% CD166+ cells; and	Plaintiff cites Capricor's data showing regional CD166 values of 98.5-99.4% in its CDC preparations.	¶20; Ex. 4B	col. 7:4-5
iv. capable of inhibiting IL2Rα expression by CD3/CD28-activated PBMCs by at least 30% relative to a control.	The complaint alleges on information and belief that Deramiocel is capable of this function, citing a study showing that CDCs derived from canine hearts suppress lymphocyte activation and reduce IL-2 receptor alpha (CD25) expression.	¶20; Ex. 4B	col. 4:9-13

• Identified Points of Contention:
  • Scope Question: A central dispute will likely be whether Capricor's product, comprised of heart-derived "cardiosphere-derived cells" (CDCs), constitutes a "mesenchymal stem cell (MSC) preparation" as that term is used in the '560 Patent, which describes MSCs derived from bone marrow '560 Patent, col. 4:60
  • Technical Question: The allegation for the "less than 0.75% CD45+ cells" limitation is based on Capricor data showing an average of 0.8%, with Plaintiff pleading infringement under the doctrine of equivalents. This signals a direct factual dispute over whether the accused product's profile is substantially the same.
  • Evidentiary Question: The evidence for the IL2Rα inhibition function relies on a study of canine cells. This raises the question of whether data from a different species is sufficient to prove that the accused human cell product performs the function required by the claim.

V. Key Claim Terms for Construction

• The Term: "mesenchymal stem cell (MSC) preparation" '560 Patent, claim 1

• Context and Importance: The definition of this term is critical for the '560 Patent, as the accused product is described as a "cardiosphere-derived cell" (CDC) product, not an MSC product Compl. ¶18 The infringement analysis depends on whether CDCs are considered MSCs within the meaning of the patent.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The patent specification defines MSCs based on their functional properties, such as the ability to self-renew and differentiate into multiple lineages like osteoblasts, adipocytes, and chondroblasts '560 Patent, col. 1:29-41 Parties may argue this functional definition should encompass any cell type, regardless of name or origin, that exhibits these properties.
  • Evidence for a Narrower Interpretation: The specification repeatedly discusses MSCs in the context of being derived from "bone marrow aspirate" (BMA) '560 Patent, col. 4:60 The detailed examples for producing the claimed preparations all start with BMA '560 Patent, col. 27:18-24 Parties may argue that this consistent context limits the term "MSC preparation" to those derived from bone marrow, excluding products derived from heart tissue.

• The Term: "mesenchymal stem cell aggregates" ('004 Patent, claim 1)

• Context and Importance: Infringement of the '004 Patent hinges on whether the "multicellular cardiospheres" formed during the manufacture of Deramiocel constitute "aggregates" under the patent's definition Compl. Ex. 4A Practitioners may focus on this term because it appears to be used differently by the parties.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification broadly refers to "aggregation" as the formation of "a cluster grouped to one or more other individual cells" '004 Patent, col. 8:1-8 This general definition could be argued to encompass purposefully grown structures like cardiospheres.
  • Evidence for a Narrower Interpretation: The patent's "Background of the Invention" and "Summary of the Invention" frame "aggregation" as a problem to be solved, referring to it as a cause of reduced efficacy and adverse reactions '004 Patent, col. 1:59-62 '004 Patent, col. 4:18-25 This could support an interpretation that the claimed "aggregates" refer to unintended, unwanted cell clumps, not intentionally formed cardiospheres.

VI. Other Allegations

• Indirect Infringement: The complaint alleges both induced and contributory infringement for all three asserted patents. The allegations are based on Defendant's knowledge of the patents (at least from the date of the complaint), its design and manufacture of Deramiocel, and its entry into commercialization and distribution agreements with third parties Compl. ¶¶35, 45, 55 Plaintiff further alleges that Deramiocel is a material part of the claimed inventions, has no substantial non-infringing uses, and is specially made for use in an infringing manner Compl. ¶¶35, 45, 55
• Willful Infringement: The complaint does not use the term "willful" but requests a finding that the case is "exceptional" and an award of attorneys' fees under 35 U.S.C. § 285 for all three patents Compl. ¶¶38, 48, 58 This claim is predicated on knowledge of the patents alleged to arise from the filing of the complaint itself (Compl. ¶35), suggesting the allegation is based on post-suit conduct.

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

• A core issue will be one of definitional scope: can the term "mesenchymal stem cell (MSC) preparation," which is described in the '560 patent in the context of bone marrow-derived cells, be construed to cover the accused "cardiosphere-derived cell" product, which originates from heart tissue? This same question of cell type equivalency is central to all three asserted patents.
• A second key issue will be one of evidentiary sufficiency: does the evidence presented in the complaint, such as data from canine cells for a functional limitation in the '560 patent or inferences from manufacturing filtration steps for a size limitation in the '004 patent, provide sufficient factual support to demonstrate that the accused human cell product meets the specific quantitative and functional requirements of the claims?
• A third question will concern the doctrine of equivalents, particularly for the '560 patent's requirement of "less than 0.75% CD45+ cells." Given the complaint's reliance on data showing the accused product has an average of 0.8% CD45+ cells, the court will have to determine if this difference is insubstantial, a determination that could be dispositive for infringement of that patent.