Common stock, par value $0.0001 per share

Zenas BioPharma, Inc.

852 Winter Street, Waltham, MA, 02451

SR One Capital Management, LLC ("SR One Capital Management"); SR One Capital Fund II Aggregator, LP ("SR One Fund II Aggregator"); SR One Capital Partners II, LP ("SR One Partners II"); AMZL, LP ("AMZL"); SR One Capital SMA Partners, LP ("SMA Partners"); SR One Capital Opportunities Fund I, LP ("SR One Opportunities Fund I"); SR One Capital Opportunities Partners I, LP ("SR One Opportunities Partners I"); and Simeon George, M.D. ("Dr. George"). SR One Fund II Aggregator is directly controlled by its general partner, SR One Partners II. AMZL is directly controlled by its general partner, SMA Partners. SR One Opportunities Fund I is directly controlled by its general partner, SR One Opportunities Partners I. SR One Partners II, SMA Partners and SR One Opportunities Partners I are directly controlled by their general partners, SR One Capital Management, and Dr. George controls SR One Capital Management. Accordingly, each of SR One Capital Management and Dr. George may be deemed to have voting and dispositive power with respect to the SR One Fund II Aggregator Shares, the AMZL Shares and the SR One Opportunities Fund I Shares (each as defined below). The persons named in this Item 2 are referred to individually herein as a "Reporting Person" and collectively as the "Reporting Persons." SR One Fund II Aggregator, AMZL and SR One Opportunities Fund I are referred to collectively as the "Funds."

The address of each Reporting Person for purposes of this filing is c/o SR One Capital Management, LP, 929 Main Street, Suite 200, Redwood City, CA 94063.

The principal business of the Funds is to invest in and assist growth-oriented businesses. The principal business of SR One Partners II is to act as the sole general partner of SR One Fund II Aggregator. The principal business of SMA Partners is to act as the sole general partner of AMZL. The principal business of SR One Opportunities Partners I is to act as the sole general partner of SR One Opportunities Fund I. The principal business of SR One Capital Management is to act as the sole general partner of SR One Partners II, SMA Partners, SR One Opportunities Partners I and a number of affiliated partnerships with similar businesses. The principal business of Dr. George is to manage SR One Capital Management.

During the five years prior to the date hereof, none of the Reporting Persons has been convicted in a criminal proceeding or has been a party to a civil proceeding ending in a judgment, decree or final order enjoining future violations of, or prohibiting activities subject to, federal or state securities laws or finding any violation with respect to such laws.

SR One Fund II Aggregator, SR One Partners II, AMZL, SMA Partners, SR One Opportunities Fund I, and SR One Opportunities Partners I are limited partnerships organized under the laws of the State of Delaware. SR One Capital Management is a limited liability company organized under the laws of the State of Delaware. Dr. George is a United States citizen.

The percentage of outstanding shares of Common Stock which may be deemed to be beneficially owned by each Reporting Person is set forth on Line 13 of such Reporting Person's cover sheet. Such percentage was calculated based on 65,176,723 shares of Common Stock reported by the Issuer to be outstanding as of July 31, 2026, on the Issuer's Form 10-Q filed with the Securities Exchange Commission on August 13, 2026.

Regarding the number of shares as to which such person has: (i) sole power to vote or to direct the vote: See line 7 of cover sheets (ii) shared power to vote or to direct the vote: See line 8 of cover sheets (iii) sole power to dispose or to direct the disposition: See line 9 of cover sheets (iv) shared power to dispose or to direct the disposition: See line 10 of cover sheets

None of the Reporting Persons has effected any transaction in shares of Common Stock during the last 60 days.

No other person is known to have the right to receive or the power to direct the receipt of dividends from, or any proceeds from the sale of, Common Stock beneficially owned by any of the Reporting Persons.

Not applicable.