X0609 4 2026-06-15 0 0001953926 Zenas BioPharma, Inc. ZBIO 0001808592 von Moltke Lisa false C/O ZENAS BIOPHARMA, INC. 852 WINTER ST., SUITE 250 WALTHAM MA 02451 0 1 0 0 See Remarks 0 Stock Option (Right to Buy) 18.71 2026-06-15 4 A 0 150000 0 A 2036-06-15 Common Stock 150000 150000 D The option vests as to 25% of the underlying shares of common stock on June 15, 2027, the first anniversary of the vesting commencement date, and as to the remaining shares, in equal monthly installments over 36 months thereafter, subject to continued service. Head of Research and Development and Chief Medical Officer By: /s/ Jeffrey Held, Attorney-in-Fact 2026-06-17