The incidence of Dose Limiting Toxicities (DLTs) that occur within 28 days following EB103 T-cell infusion will be assessed. A DLT consists of any adverse event (AE) or abnormal laboratory value assessed as unrelated to disease, disease progression, concomitant medication, or intercurrent illness that occurs within 28 days following EB103 T-cell infusion and meets specified criteria as outline in the clinical protocol. The type, frequency, and severity of each DLT, AE, and abnormal laboratory value will be documented to assess the safety and tolerability of EB103.

The type, frequency, and severity of Treatment-Emergent Adverse Events (TEAEs) will be assessed and includes an AE that starts any time from initiation of EB103 administration through and including 90 days after EB103 administration. Listing and summaries will be prepared for the following type of events: TEAEs, SAEs, Grade 3 or higher AEs, treatment related AEs (conditioning chemotherapy, protocol-mandated procedures, or EB103), and AEs leading to death. AESIs, including but not limited to acute infusion reaction, CRS, ICANS, prolonged cytopenia, TLS, MAS/HLH, SPM, and hypogammaglobulinemia.

The type, frequency, and severity after Treatment-Emergent Laboratory Abnormalities will be assessed and includes a laboratory abnormality that, compared to baseline, worsens by at least one grade with 90 days after EB103 administration.

The RP2D will be determined by the study Dose Escalation Committee (DEC) and chosen based on the maximum tolerated dose (MTD) but will not exceed the MTD and the maximum administered dose (MAD). The RP2D will also be based on the manufacturing capability.