Cabaletta Bio (CABA) Status Update summary

Clinical program and trial updates

• The RESET clinical program is active at 40 U.S. sites, with 16 patients enrolled and 10 dosed as of November 12, 2024; European expansion is planned following EMA CTA authorization.

• CABA-201 is being evaluated in five Phase 1/2 trials for lupus, myositis, systemic sclerosis, myasthenia gravis, and pemphigus vulgaris, using consistent trial designs and weight-based dosing.

• FDA Fast Track Designation has been granted for CABA-201 in multiple indications, with anticipated FDA meetings on registrational trial design as early as 2025.

• The program leverages oncology experience, includes a 15-year follow-up, and is supported by a cash runway into the first half of 2026.

Patient population and unmet needs

• Patients enrolled had active, refractory autoimmune disease, most having failed prior B cell-targeting therapies.

• Autoimmune conditions targeted include myositis, SLE, and systemic sclerosis, all associated with high morbidity and reduced quality of life.

• Key inclusion criteria required active disease despite standard treatments; exclusion criteria included prior B cell depletion, CAR T therapy, or significant organ impairment.

Safety and risk management

• CABA-201 showed a favorable safety profile, with most patients experiencing no CRS, ICANS, or serious infections; three of eight had low-grade CRS, all resolved with standard care.

• One lupus nephritis patient had late-onset pancytopenia and reversible grade 4 ICANS; protocol now includes a two-week delay for recent fever/infection and recommends antiseizure prophylaxis.

• No new ICANS events were observed since August 2024; adverse event management follows established oncology protocols.

• Independent data monitoring committee recommended study continuation without changes after an unrelated serious adverse event.