Exhibit 1.1 17,650,000 Shares ALUMIS INC. VOTING COMMON STOCK, PAR VALUE $0.0001 PER SHARE UNDERWRITING AGREEMENT January 7, 2026 January 7, 2026 Morgan Stanley & Co. LLC Leerink Partners LLC Cantor Fitzgerald & Co. As Representatives of the several Underwriters named in Schedule I hereto. c/o Morgan Stanley & Co. LLC 1585 Broadway New York, NY 10036 c/o Leerink Partners LLC 1301 Avenue of the Americas 5th Floor New York, NY 10019 c/o Cantor Fitzgerald & Co. 110 East 59th Street 6th Floor New York, NY 10022 ...