Cabaletta Bio, Inc.

We are a late clinical-stage biotechnology company focused on the discovery and development of innovative engineered T cell therapies that have the potential to provide deep and durable, perhaps curative, responses with one-time administration for patients with autoimmune diseases. Our proprietary CABA , or Cabaletta Approach to B cell Ablation platform, focuses on the CARTA approach. CARTA refers to Chimeric Antigen Receptor T cells for Autoimmunity and is designed to potentially reset the immune system. Based on clinical data reported to date, we believe our CABA platform has the potential to safely enable complete and durable responses for a broad range of autoimmune diseases and that it has potential applicability across dozens of autoimmune diseases that we have identified, evaluated and prioritized. Resecabtagene autoleucel, or rese-cel (formerly referred to as CABA-201), is a 4-1BB co-stimulatory domain-containing fully human CD19-CAR T construct designed to treat patients with a broad range of autoimmune diseases and our lead product candidate within the CARTA strategy. Rese-cel is designed to achieve transient and deep depletion of all B cells following a single, weight-based infusion of T cells that are engineered to express an antibody fragment that recognizes a B cell receptor expressed on the surface of all B cells. The construct is designed to allow for the deep elimination of all B cells, including all B cells that contribute to disease, with subsequent repopulation by healthy transitional, na ve B cells.