Cabaletta Bio Reports One-Year Rese-cel Responses in Dermatomyositis and Safety Profile Across 71 Autoimmune Disease Patients

Key Points

• Cabaletta Bio reported one-year Phase 1/2 data for resecabtagene autoleucel (rese-cel), an investigational CD19 CAR T cell therapy, across dermatomyositis, lupus nephritis, and systemic sclerosis.
• All six dermatomyositis patients maintained immunomodulator-free moderate-to-major Total Improvement Score responses through one year.
• Across 71 treated patients, 94% experienced no or Grade 1 cytokine release syndrome and 96% had no immune effector cell-associated neurotoxicity syndrome.

Cabaletta Bio, a late-stage clinical biotechnology company developing cell therapies for autoimmune diseases, announced new Phase 1/2 data on resecabtagene autoleucel (rese-cel) in three oral and poster presentations at the American College of Rheumatology (ACR) Convergence 2026 annual meeting in Orlando, Florida. The company also hosted an industry-supported symposium on rese-cel and its RESET clinical development program.

Findings come from Phase 1/2 patients treated in open-label, single-arm studies with a single weight-based infusion of rese-cel following preconditioning, as of a September 4, 2026 data cutoff. Nearly all patients discontinued all immunomodulators and required no or only low-dose steroids while achieving durable improvement in disease activity.

“In three different autoimmune diseases where patients are at risk of severe disability, end-organ damage, and increased risk of death despite current therapies, a single weight-based dose of rese-cel delivered immunomodulator-free clinical improvements that were durable through at least one year with a favorable benefit-risk profile,” said David J. Chang, M.D., Chief Medical Officer of Cabaletta.

Dermatomyositis Responses at One Year

All six dermatomyositis patients (6/6) maintained an immunomodulator-free moderate-to-major Total Improvement Score (TIS) response through one year, with five of six reaching that level by Week 16, the primary-endpoint timepoint for the registrational dermatomyositis and antisynthetase syndrome cohort. Most patients were also free of steroids at Week 52. Improvements were reported in muscle strength and skin manifestations, as well as patient-reported physical function and fatigue.

Cabaletta expects to report topline results from the registrational adult dermatomyositis and antisynthetase syndrome cohort in the second half of 2027 and to submit a Biologics License Application for rese-cel in myositis, including adult dermatomyositis and available juvenile dermatomyositis Phase 1/2 data, in the first quarter of 2028.

Lupus Nephritis and Systemic Sclerosis

All five lupus nephritis patients who underwent an optional repeat kidney biopsy achieved DORIS remission off all immunomodulators and on no or low-dose steroids, and all five demonstrated histologic response or remission. Cabaletta believes these data provide insight for assessing clinical responses in lupus nephritis patients who show histologic response or remission without meeting complete renal response criteria, where persistent proteinuria is consistent with structural kidney damage predating treatment rather than ongoing disease activity.

Among seven systemic sclerosis patients, five achieved rCRISS-50 at one year and six achieved rCRISS-25. The five patients with interstitial lung disease showed a 9% mean improvement in percent-predicted forced vital capacity at one year. Patients also improved on the modified Rodnan Skin Score. Cabaletta is enrolling a registrational systemic sclerosis cohort focused on interstitial lung disease.

Safety Across 71 Patients

Across 71 patients with myositis, systemic sclerosis, lupus, and myasthenia gravis, 94% (67/71) experienced no or Grade 1 cytokine release syndrome, with Grade 2 reported in four patients. A total of 96% (68/71) had no immune effector cell-associated neurotoxicity syndrome, and no immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome was reported. Cabaletta attributes the reported benefit-risk profile to the therapy’s combination of construct and production elements, including a fully human CD19 binder, weight-based dosing, and a nine-day manufacturing process.

Rese-cel is an investigational chimeric antigen receptor (CAR) T cell therapy containing a fully human CD19 binder and designed to achieve immune reset in autoimmune diseases. It is administered as a single weight-based intravenous infusion after discontinuation of immunomodulators. The RESET program spans multiple single-arm, company-sponsored trials in rheumatology, neurology, and dermatology, with disease-specific cohorts designed to evolve into registrational studies.

Want to keep up on regenerative medicine? Get the weekly newsletter here.