License Agreements	6 Months Ended
Jun. 30, 2025
License Agreements
License Agreements	8.License Agreements License Agreements with Xencor, Inc. 2020 Xencor Agreement In September 2020, the Company entered into a license agreement (the “2020 Xencor Agreement”) with Xencor, Inc. (“Xencor”), under which the Company is required to pay Xencor tiered royalties on annual net sales of successfully commercialized products, including ZB002 and ZB004. The royalty percentage rates vary by geographic areas as defined in the 2020 Xencor Agreement and range from the mid-single digits to mid-teens. The Company is also obligated to reimburse Xencor for third-party costs incurred for certain patent filings, prosecution and maintenance as further specified in the 2020 Xencor Agreement. During the six months ended June 30, 2025 and 2024, the Company incurred no such reimbursable costs. 2021 Xencor Agreement In May 2021, the Company entered into a license agreement with Xencor (the “2021 Xencor Agreement”), under which the Company obtained an exclusive, royalty-bearing, sublicensable worldwide license to research, develop, manufacture, market and sell obexelimab. The Company is also obligated to make regulatory milestone payments up to $75.0 million and one-time sales milestone payments up to $385.0 million upon achieving milestone events of net sales in a given calendar year in the territory equal to certain threshold amounts. In addition, the Company is required to pay Xencor tiered royalties on annual net sales of successfully commercialized products utilizing obexelimab, with the royalty percentages varying based on regions and ranging from the mid-single digits to the mid-teens. For the six months ended June 30, 2025 and 2024, the Company recorded no reimbursable patent-related costs. License Agreement with Viridian Therapeutics, Inc. In October 2020, the Company entered into a license agreement with Viridian Therapeutics, Inc. (the “Viridian Agreement”) to obtain an exclusive, royalty-bearing, sublicensable license to research, develop, manufacture, market and sell certain antibody product candidates based on Viridian’s proprietary technology. The Company’s license rights are limited to non-oncology indications and are limited to China, Hong Kong, Macau and Taiwan (“Zenas Territories”). Viridian retains its rights to develop and commercialize such product candidates outside of the Zenas Territories. In December 2021, the Company and Viridian entered into two letter agreements to authorize initiation of certain manufacturing and development activities related to the licensed product candidate, ZB001. Under the terms of the letter agreements, Viridian engaged a third-party contract manufacturer to initiate certain work related to ZB001. In May 2022, the Company entered into a manufacturing development and supply agreement (“Viridian Supply Agreement”). In January 2025, the Company entered into a third amendment to the Viridian Agreement, under which the Company is obligated to make development and sales milestone payments to Viridian, totaling $21.0 million, based on achievement of certain specified development and sales milestones, and royalties on net sales. In January 2025, the Company entered the Zai License Agreement under which the Company granted Zai an exclusive sublicense to develop, manufacture and commercialize ZB001 and related programs in greater China. In connection with the Zai License Agreement, the Company assigned the Viridian Supply Agreement to Zai. For additional information on the Zai Agreement, please see License Agreement with Zai Lab (Hong Kong) Limited in Note 7 – License and Collaboration Revenue to these condensed consolidated financial statements. During the three and six months ended June 30, 2025, the Company recognized no expense related to Viridian contract manufacturing organization (“CMO”) costs. During the three and six months ended June 30, 2024, the Company recognized $0.1 million in expense related to Viridian CMO costs. Viridian has agreed to reimburse the Company for certain services the Company performs on Viridian’s behalf, with reimbursements being recorded as a reduction in research and development expenses. During the three and six months ended June 30, 2025, the Company recorded an immaterial amount and $0.2 million in reimbursable expenses, respectively. During the three and six months ended June 30, 2024, the Company recorded $1.0 million in reimbursable expenses. Additionally, during the six months ended June 30, 2025 and 2024, no milestones were achieved.

License Agreements

6 Months Ended

Jun. 30, 2025

8.License Agreements

License Agreements with Xencor, Inc.

2020 Xencor Agreement

In September 2020, the Company entered into a license agreement (the “2020 Xencor Agreement”) with Xencor, Inc. (“Xencor”), under which the Company is required to pay Xencor tiered royalties on annual net sales of successfully commercialized products, including ZB002 and ZB004. The royalty percentage rates vary by geographic areas as defined in the 2020 Xencor Agreement and range from the mid-single digits to mid-teens. The Company is also obligated to reimburse Xencor for third-party costs incurred for certain patent filings, prosecution and maintenance as further specified in the 2020 Xencor Agreement. During the six months ended June 30, 2025 and 2024, the Company incurred no such reimbursable costs.

2021 Xencor Agreement

In May 2021, the Company entered into a license agreement with Xencor (the “2021 Xencor Agreement”), under which the Company obtained an exclusive, royalty-bearing, sublicensable worldwide license to research, develop, manufacture, market and sell obexelimab. The Company is also obligated to make regulatory milestone payments up to $75.0 million and one-time sales milestone payments up to $385.0 million upon achieving milestone events of net sales in a given calendar year in the territory equal to certain threshold amounts. In addition, the Company is required to pay Xencor tiered royalties on annual net sales of successfully commercialized products utilizing obexelimab, with the royalty percentages varying based on regions and ranging from the mid-single digits to the mid-teens.

For the six months ended June 30, 2025 and 2024, the Company recorded no reimbursable patent-related costs.

License Agreement with Viridian Therapeutics, Inc.

In October 2020, the Company entered into a license agreement with Viridian Therapeutics, Inc. (the “Viridian Agreement”) to obtain an exclusive, royalty-bearing, sublicensable license to research, develop, manufacture, market and sell certain antibody product candidates based on Viridian’s proprietary technology. The Company’s license rights are limited to non-oncology indications and are limited to China, Hong Kong, Macau and Taiwan (“Zenas Territories”). Viridian retains its rights to develop and commercialize such product candidates outside of the Zenas Territories. In December 2021, the Company and Viridian entered into two letter agreements to authorize initiation of certain manufacturing and development activities related to the licensed product candidate, ZB001. Under the terms of the letter agreements, Viridian engaged a third-party contract manufacturer to initiate certain work related to ZB001. In May 2022, the Company entered into a manufacturing development and supply agreement (“Viridian Supply Agreement”). In January 2025, the Company entered into a third amendment to the Viridian Agreement, under which the Company is obligated to make development and sales milestone payments to Viridian, totaling $21.0 million, based on achievement of certain specified development and sales milestones, and royalties on net sales.

In January 2025, the Company entered the Zai License Agreement under which the Company granted Zai an exclusive sublicense to develop, manufacture and commercialize ZB001 and related programs in greater China. In connection with the Zai License Agreement, the Company assigned the Viridian Supply Agreement to Zai. For additional information on the Zai Agreement, please see License Agreement with Zai Lab (Hong Kong) Limited in Note 7 – License and Collaboration Revenue to these condensed consolidated financial statements.

During the three and six months ended June 30, 2025, the Company recognized no expense related to Viridian contract manufacturing organization (“CMO”) costs. During the three and six months ended June 30, 2024, the Company recognized $0.1 million in expense related to Viridian CMO costs. Viridian has agreed to reimburse the Company for certain services the Company performs on Viridian’s behalf, with reimbursements being recorded as a reduction in research and development expenses. During the three and six months ended June 30, 2025, the Company recorded an immaterial amount and $0.2 million in reimbursable expenses, respectively. During the three and six months ended June 30, 2024, the Company recorded $1.0 million in reimbursable expenses. Additionally, during the six months ended June 30, 2025 and 2024, no milestones were achieved.