# Targeting BCMA+ Cells with RNA-engineered CAR T cells to treat Lupus: A Phase 2 clinical study

> **NIH NIH U44** · CARTESIAN THERAPEUTICS, INC. · 2024 · $149,008

## Abstract

Systemic lupus erythematosus (SLE) is an autoimmune disease that impacts over 3 million people, causing
joint pain, organ damage, and impaired quality of life. Existing SLE drugs are non-specific and cause side
effects. With NIAID Fast-Track U44 support, we will test a new cell therapy technology as a safe and potent
treatment for SLE. The goal of chimeric antigen receptor T cell (CAR-T) therapy is to eliminate pathogenic
cells by engineering CARs to bind antigens on a target cell. This involves isolation and engineering of patient
T cells to express CAR, followed by reinfusion. All approved CAR-T therapies rely on transfection of T cells
with DNA that permanently modifies the genome and requires proliferation for efficacy. For these cells to
thrive and expand, patients must first be admitted to the hospital to receive preconditioning chemotherapy.
Beyond these burdens, permanent CAR expression resulting from DNA engineering causes unconstrained
proliferation and toxicity that drive costs as high as $2.0M. These hurdles have limited CAR-T cell treatment
only to advanced refractory cancers. We have designed a new approach for CAR-T using RNA to achieve
transient CAR expression (rCAR-T). These cells do not require proliferation, instead relying on rapid depletion
of target cells as CAR expression decays during cell division. This feature limits toxicity, eliminating
preconditioning chemotherapy and inpatient stays. Thus, rCAR-T creates a unique opportunity to expand cell
therapy to autoimmunity. We have engineered cells with rCAR-T to bind B cell maturation antigen (BCMA),
an antigen on the plasma cells (PCs) that secrete the pathogenic autoantibodies characteristic of many
autoimmune diseases. This therapy – “Descartes-08” – transiently expresses anti-BCMA CAR to eliminate
BCMA+ PCs after infusion without inducing serious toxicity. In a Phase 2a trial (NCT04146051), Descartes-
08 conferred potent, safe, and long-lasting improvement in patients with Myasthenia Gravis, an autoantibody
associated autoimmune disorder (AAAD) in which PCs produce autoantibodies targeting neuromuscular
junctions. Since BCMA+ PCs also produce the autoantibodies that attack ubiquitous nuclear antigens in SLE,
here we will test if Descartes-08 provides safe, effective, and durable treatment of SLE. In July 2023 the FDA
allowed our IND for SLE; we have initiated a Phase 2a open label trial in patients with SLE (NCT06038474).
In SBIR Phase 1, we will use data from this trial to finalize design of a randomized, placebo-controlled Phase
2b trial (RCT) for SLE that will be executed in SBIR Phase 2. The aims are: i) Finalize the design and operating
procedures for the Phase 2b Descartes-08 RCT in SLE, ii) Show Descartes-08 drives clinical benefit, reduced
autoantibodies, & phenotypic changes in RCT, and iii) Show the safety and tolerability of Descartes-08 in
patients with SLE during the Phase 2b RCT. This plan is aligned with the U44 Cooperative Mechanism
requirements because De...

## Key facts

- **NIH application ID:** 10929738
- **Project number:** 1U44AI184200-01
- **Recipient organization:** CARTESIAN THERAPEUTICS, INC.
- **Principal Investigator:** Christopher M Jewell
- **Activity code:** U44 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $149,008
- **Award type:** 1
- **Project period:** 2024-08-14 → 2026-01-14

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10929738

## Citation

> US National Institutes of Health, RePORTER application 10929738, Targeting BCMA+ Cells with RNA-engineered CAR T cells to treat Lupus: A Phase 2 clinical study (1U44AI184200-01). Retrieved via AI Analytics 2026-06-12 from https://api.ai-analytics.org/grant/nih/10929738. Licensed CC0.

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