Pipeline

Cartesian is advancing its pipeline of mRNA cell therapies, which includes multiple clinical assets, for the treatment of autoimmune conditions. Cartesian is also pursuing new ideas in its discovery programs.

Asset Indication Discovery / Preclinical Phase 1 Phase 2 Phase 3
Descartes-08 Autologous mRNA CAR-T
Myasthenia Gravis (MG)
Systemic Lupus Erythematosus (SLE)
Myositis*
  • * Includes juvenile dermatomyositis in addition to adult myositis indications

Descartes-08

Descartes-08, Cartesian’s lead candidate, is an mRNA chimeric antigen receptor T-cell cell therapy (mRNA CAR-T) in clinical development for autoimmune disease. CAR-T cell therapy involves modifying a patient’s T cells—key components of the immune system that help identify and attack pathogens—to selectively target and suppress the immune responses that are believed to contribute to their condition.

Descartes-08 is an autologous mRNA CAR-T, which means it uses a patient’s own T cells modified with mRNA to help them better target and fight their disease. More specifically, Descartes-08 targets B-cell maturation antigen (BCMA), a cell surface protein involved in regulating immune responses, to help modulate the overactive immune activity seen in certain autoimmune diseases.

Descartes-08 is designed to be dosed safely in an outpatient setting without pretreatment chemotherapy. In a Phase 2 clinical trial in patients with generalized myasthenia gravis (MG), Descartes-08 was observed to be well tolerated, and adverse events were transient and mostly mild, supporting outpatient administration without the need for pretreatment chemotherapy.

Cartesian is developing Descartes-08 for the treatment of generalized MG and myositis.

Learn More About Generalized
Myasthenia Gravis
Learn More About Myositis
Learn More About Systemic Lupus
Erythematosus

Cartesian has been awarded several grants related to Descartes-08 from the National Institutes of Health (NIH) and is working with the NIH to advance the development of Descartes-08 through a research partnership. Descartes-08 has been granted Regenerative Medicine Advanced Therapy Designation and Orphan Drug Designation for the treatment of MG, as well as Rare Pediatric Disease Designation for the treatment of JDM, by the U.S. Food and Drug Administration.

These FDA-sponsored designations support Cartesian, offering benefits at different stages throughout clinical development and the potential approval process. For example, receiving RMAT Designation offers sponsor companies the benefits of the fast track and breakthrough therapy designation programs, allowing for early, close, and frequent interactions with the FDA with the goal of expediting drug development.

Descartes-15

Descartes-15 is Cartesian’s next-generation autologous B cell maturation antigen (BCMA)-directed mRNA-engineered chimeric antigen receptor T-cell therapy (mRNA CAR-T). Descartes-15 is designed to have predictable and controllable pharmacokinetics, including technological advances that enhance CAR stability even in the presence of target-driven suppression of CAR.

Similar to Descartes-08, the Company’s lead product candidate, Descartes-15 is designed to be administered without preconditioning chemotherapy and does not use integrating vectors. Relative to Descartes-08, Descartes-15 has been observed to achieve an approximately ten-fold increase in CAR expression and selective target-specific killing in preclinical studies.

A Phase 1 dose escalation trial (NCT04816526) demonstrated favorable safety and tolerability data in participants treated with Descartes-15. Cartesian plans to pause the development of Descartes-15 to prioritize later-stage opportunities with Descartes-08 in MG and myositis.

Myasthenia Gravis

Generalized myasthenia gravis (MG) is a chronic autoimmune disorder that causes disabling muscle weakness and fatigue. It affects over 120,000 people across the U.S. and E.U. Patients often suffer from visual disturbances such as double vision, along with difficulties in speaking, swallowing, and even breathing. There is currently no cure for MG, and treatment typically requires chronic immunosuppressive medicines, with their attendant risks and side effects.

In a Phase 2b double-blind, placebo-controlled study (NCT04146051), MG participants who received Descartes-08 experienced deep and durable responses over time, with statistically significant and clinically meaningful improvements in symptoms compared to participants who received placebo. Consistent with previously reported results from the Phase 2a open-label portion of the trial, Descartes-08 was observed to be well tolerated, and adverse events were transient and mostly mild, supporting outpatient administration without the need for pretreatment chemotherapy.

Cartesian is actively enrolling patients in the Phase 3 AURORA trial of Descartes-08 in MG (NCT06799247).

Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an incurable chronic autoimmune disease marked by systemic inflammation that affects multiple organ systems including the skin, joints, kidneys, brain, and heart. The symptoms of SLE can range from mild to life-threatening and often include fatigue, joint pain, rash, and fever. SLE impacts approximately 1.5 million people in the U.S.

Initial data reported significant reduction in disease activity following initial Descartes-08 treatment with 100% of participants who reached Month 3 follow-up (n=3) achieving Lupus Low Disease Activity State (LLDAS) response, defined by specific criteria that indicate low disease activity, improved patient outcomes, and sustained symptom improvement. These results further validate the clinical effect of Descartes-08 in the field of autoimmune disease and the company will continue to analyze the data from SLE to determine the next steps for the program.

Myositis

Myositis is a rare set of pathogenic autoantibody-driven diseases characterized by inflammation and muscle weakness. Myositis symptoms can range from mild to life-threatening and symptoms often include muscle weakness, joint or muscle pain, fatigue, swelling, trouble breathing or swallowing, and arrythmia. Myositis impacts approximately 80,000 people in the United States. With strong mechanistic alignment with existing clinical data in MG and SLE, Cartesian plans to expand the use of Descartes-08 into myositis, a significantly underserved market with high unmet need. The Company plans to initiate a seamless adaptive clinical trial design which provides a potential opportunity for a single pivotal trial planned to commence in the first half of 2026.