Cabaletta Bio: rese-cel responses last a year in three autoimmune diseases in Phase 1/2

Cabaletta Bio (Nasdaq: CABA), a Philadelphia company, reported that small groups of patients with dermatomyositis, lupus nephritis and systemic sclerosis kept clinical responses for at least one year after a single infusion of the experimental cell therapy resecabtagene autoleucel (rese-cel), according to mychesco.com. mychesco.commychesco.commychesco.comOpen source ↗ The data were presented at the American College of Rheumatology's Convergence 2026 meeting in Orlando, Florida. Patients remained off immunomodulatory medications.

The results come from open-label, single-arm Phase 1/2 studies. Patients received one weight-based infusion of rese-cel after preconditioning treatment. The data cutoff was Sept. 4, 2026.

Responses by disease

All six dermatomyositis patients evaluated at one year maintained a moderate-to-major response on the Total Improvement Score without immunomodulatory medications. Five of the six (83%) had reached that response by Week 16, the primary endpoint time point in the company's ongoing registrational study. Most patients were off steroids at Week 52, and improvements extended to muscle strength, skin disease activity, physical function and fatigue.

In lupus nephritis, five patients who underwent optional repeat kidney biopsies all met the DORIS definition of remission, taking no immunomodulators and either no steroids or low-dose steroids. Biopsies showed histologic response or remission in all five. Because the biopsies were optional, the findings apply only to those patients. mychesco.commychesco.commychesco.comOpen source ↗

In systemic sclerosis, five of seven patients achieved an rCRISS-50 response at one year, and six of seven (86%) achieved the less stringent rCRISS-25. In five patients with interstitial lung disease, average percent-predicted forced vital capacity improved by 9%. Skin involvement, measured by the modified Rodnan Skin Score, also improved.

Safety and next steps

Safety data covered 71 patients treated with rese-cel after preconditioning in myositis, systemic sclerosis, lupus and myasthenia gravis studies. Of these, 67 (94%) had no cytokine release syndrome or Grade 1 symptoms, and four (6%) had Grade 2. Sixty-eight of 71 (96%) had no immune effector cell-associated neurotoxicity syndrome, and no cases of IEC-HS-like syndrome were reported.

The groups are small (six, five and seven patients in the efficacy analyses) and the studies had no randomized comparison arm, so the data do not show how rese-cel compares with existing treatments. mychesco.commychesco.commychesco.comOpen source ↗

The company expects topline results from its registrational adult dermatomyositis and antisynthetase syndrome cohort in the second half of 2027. It plans to submit a Biologics License Application to the FDA in the first quarter of 2028 for myositis. A registrational systemic sclerosis cohort in patients with interstitial lung disease is enrolling.