To assess safety and tolerability of escalating doses of MT-601 by the number of participants with MT-601 Dose Limiting Toxicities (DLTs) and Safety events (including but not limited to): treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), deaths, and clinical laboratory abnormalities per National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE, Version 5.0)

To assess anti-tumor activity of MT-601 based on Lugano Classification by the following endpoints: * Objective response rate (ORR) defined as the proportion of treated patients who achieve a best response of complete remission (CR) or partial response (PR) per Lugano Classification. * The Clopper-Pearson method will be used to estimate the two-sided exact 95% confidence interval for ORR.

To assess anti-tumor activity of MT-601 based on Lugano Classification by the following endpoints: * Duration of response (DOR) defined for patients who attain a best response of CR or PR and is the time between the date of first documented CR or PR and the date of the first observed progression per Lugano Classification. * DOR will be estimated using the Kaplan-Meier (KM) product limit method. The median DOR and corresponding 95% confidence intervals (CI) will be estimated.

To assess anti-tumor activity of MT-601 based on Lugano Classification by the following endpoints: * Complete remission (CR) rate defined as the proportion of treated patients who achieve a best response of CR per Lugano Classification. * The Clopper-Pearson method will be used to estimate the two-sided exact 95% confidence interval for CR rate estimates.