CABA · Cabaletta Bio, Inc.

Cabaletta Bio, Inc. entered into a material definitive underwriting agreement on May 4, 2026, with lead underwriters TD Securities (USA) LLC, Guggenheim Securities, LLC, and Cantor Fitzgerald & Co. for a registered direct offering of 51,725,000 shares of its common stock at $2.90 per share. This pricing implies gross proceeds of approximately $150 million, with net proceeds estimated at $141 million after underwriting discounts of 6.0% ($2.726 per share purchase price) and offering expenses. The transaction is expected to close on May 5, 2026, subject to customary conditions, and utilizes the company's effective shelf registration on Form S-3 (File No. 333-278126), as amended and effective March 31, 2025. A legal opinion from Goodwin Procter LLP confirms the shares will be validly issued, fully paid, and non-assessable upon closing. The financing includes participation from Bain Capital Life Sciences, Adage Capital Management, Cormorant Asset Management, new mutual and sovereign wealth funds, and Eli Lilly and Company, signaling strong institutional support. As of March 31, 2026, the company reported $117 million in cash and equivalents. Combined with these proceeds, this extends the cash runway into mid-2027, supporting expanded clinical development of rese-cel (CABA-201), a CD19-CAR T therapy, across multiple autoimmune indications including myositis (ongoing registrational study), SLE, systemic sclerosis, myasthenia gravis, and pemphigus vulgaris, both with and without preconditioning. Funds will also advance manufacturing scalability via partnership with Cellares for automated production and prepare for commercial readiness. Item 8.01 details a press release (Exhibit 99.1) and updated corporate presentation (Exhibit 99.2), reinforcing the strategic focus on the RESET clinical program and potential BLA submission in myositis by 2027.