Cabaletta Bio Achieves 83% Registrational Endpoint Rate in Dermatomyositis Phase 1/2 Study

Cabaletta Bio's registrational path for rese-cel (resecabtagene autoleucel) is taking clearer shape: 83% of dermatomyositis patients in the Phase 1/2 RESET-Myositis study would have met the pivotal primary endpoint, with all five of those patients sustaining immunomodulator-free responses through the latest follow-up, as long as 1.5 years. The data, presented at the EULAR 2026 Congress in London (June 3–6), position the company's single-arm registrational design against a conservatively high control-group response rate requiring no more than 50% of patients to hit the 16-week primary endpoint for a positive study.

For regulatory affairs leads tracking cell therapy BLA timelines, the JDM signal carries additional weight. The first juvenile dermatomyositis patient treated with rese-cel demonstrated a moderate TIS response off immunomodulators, maintained through 32 weeks of follow-up. Cabaletta expects JDM to be included in its 2H27 myositis BLA submission, a designation that could facilitate a priority review voucher under the FDA's rare pediatric disease pathway, a meaningful cost offset for sponsors navigating late-stage cell therapy development under 21 CFR Part 211-adjacent biologics frameworks.

Systemic sclerosis has been named the second pivotal indication. Phase 1/2 data following a single dose of rese-cel upon immunomodulator discontinuation were described as convincing; a single-arm registrational study in approximately 25 SSc patients with interstitial lung disease is anticipated to initiate in 4Q26. The ILD subpopulation selection reflects a higher-acuity patient segment where durable, immunomodulator-free outcomes would carry the most clinical and regulatory differentiation.

The preconditioning-free (PC-free) program in lupus adds a manufacturing and access dimension that QA and process development teams should track. The lowest PC-free dose achieved deep B cell depletion in one of the first two lupus patients treated, with translational data described as consistent with RESET-SLE patients who achieved immune reset following standard rese-cel with preconditioning. Higher-dose PC-free cohorts are now enrolling in both lupus and pemphigus vulgaris. If the dose-response profile holds, eliminating preconditioning could materially alter the sterility assurance and logistics burden associated with outpatient cell therapy administration, a point Cabaletta's CMO flagged explicitly in supporting the outpatient administration model.

Across 52 evaluable patients spanning myositis, lupus, and systemic sclerosis, rese-cel demonstrated a predictable translational profile with and without preconditioning, consistent across indications, a finding that will inform comparability assessments as the program scales toward registrational batch manufacturing and process validation under ICH Q10 quality system expectations.

The 2H27 BLA submission timeline for myositis, if maintained, will set the clock on FDA review cycles and any priority review voucher monetization strategy that follows.

Source: Cabaletta Bio, Inc. via GlobeNewswire, June 3, 2026.