9. Related Party Transactions

Relationship with GC Cell and GC Corp

GC Cell and GC Corp, subsidiaries of Green Cross Corp, are stockholders of the Company and are represented on the Company’s board of directors.

The Company entered into license agreements in November 2019, October 2020, March 2021, and December 2022 (collectively, the License Agreements) with GC Cell (see Note 7). In August 2020, the Company entered into a Research and Service Agreement with GC Cell in which GC Cell is to provide mutually agreed research services in support of the research and development of one or more of the Selected Products that the Company has licensed from GC Cell under the License Agreements. The Company did not incur any research and development expense in connection with the agreements for the three and six months ended June 30, 2026 and 2025. As of June 30, 2026, and December 31, 2025, the Company had no accounts payable and accrued expenses in connection with the GC Cell License Agreements and Research Service Agreement.

In September 2023, the Company and GC Cell amended the AB-201 Agreement (see Note 7). The Company did not recognize any license and development support-related revenue for the three and six months ended June 30, 2026 and 2025. As of June 30, 2026, and December 31, 2025, total accounts receivable related to the Amended AB-201 Agreement was zero.

Under the AB-205 Agreement, GC Cell agreed to reimburse the Company for direct costs incurred on behalf of GC Cell in accordance with the Development Plan under the AB-205 Agreement, provided that such reimbursed costs are deemed to form part of the direct costs incurred and paid by GC Cell (see Note 7). There were no reimbursements for development costs invoiced to GC Cell in connection with the AB-205 Agreement during the three and six months ended June 30, 2026 and 2025. The Company did not receive any payments from GC Cell during the three and six months ended June 30, 2026 and 2025. As of June 30, 2026, and December 31, 2025, the Company had no receivables from GC Cell recorded in the condensed balance sheets.

In March 2020, the Company entered into the Manufacturing Agreement with GC Cell, where GC Cell is to perform manufacturing services with respect to any biological or chemical product manufactured or to be manufactured for use in Phase 1 or Phase 2 clinical trials. The Company amended the Manufacturing Agreement in June 2020 to include the Company’s right to terminate the agreement at will. In connection with the agreement, the Company incurred approximately $13 thousand and $26 thousand in research and development expenses for the three and six months ended June 30, 2026, respectively, and approximately $15 thousand and $29 thousand for the three and six months ended June 30, 2025, respectively. As of June 30, 2026, and December 31, 2025, the Company had approximately $22 thousand and zero, respectively, of accounts payable and accrued expenses in connection with the Manufacturing Agreement recorded in the condensed balance sheets.

Relationship with RA Capital

RA Capital Healthcare Fund, L.P., RA Capital Nexus Fund, L.P. and Blackwell Partners LLC—Series A (the RA Capital Funds) are stockholders of the Company and a member of the Company’s board of directors is affiliated with the RA Capital Funds.

In June 2024, the Company entered into a services agreement (the Blackbird Services Agreement) with Blackbird Clinical, Inc. (Blackbird), an entity controlled by RA Capital Management, L.P. RA Capital Management, L.P. is the investment manager for the RA Capital Funds. Under the terms of the Blackbird Services Agreement, Blackbird provides consulting services in connection with the Company's clinical trials, including study strategy, clinical operations and patient operations. The agreement commenced on June 1, 2024 and was in effect until June 1, 2025. The Company did not incur any research and development expenses in connection with the consulting services from Blackbird for the three and six months ended June 30, 2026 and 2025. As of June 30, 2026, and December 31, 2025, the Company had no accounts payable and accrued expenses in connection with the Blackbird Services Agreement recorded in the condensed balance sheets.

In November 2024, the Company entered into a services agreement (the Carnot Services Agreement) with Carnot Pharma, LLC (Carnot), an entity controlled by RA Capital Management, L.P. RA Capital Management, L.P. is the investment manager for the RA Capital Funds. Under the terms of the Carnot Services Agreement, Carnot provides consulting services in connection with the Company's clinical trials, including clinical operations and patient advocacy in support of the Company’s AlloNK autoimmune programs. The agreement commenced on November 1, 2024 and was in effect until December 31, 2025. The Company did not incur any research and development expenses in connection with the consulting services from Carnot for the three and six months ended June 30, 2026. The Company incurred approximately $12 thousand and $31 thousand in research and development expenses in connection with consulting services from Carnot for the three and six months ended June 30, 2025, respectively. As of June 30, 2026,

and December 31, 2025, the Company had no accounts payable and accrued expenses in connection with the Carnot Services Agreement recorded in the condensed balance sheets.