This is a phase I, multicenter, open label, sequential-cohort, dose escalation study of ESG206. The purpose is to evaluate the clinical safety, tolerability, PK (pharmacokinetics), and preliminary efficacy and to establish the MTD (maximum tolerated dose), if any, and RP2D (recommended phaseII dose) of ESG206 in adult subjects with B lymphoid malignancies.

Inclusion Criteria:

• Willing and able to provide written informed consent for the trial.
• Male or female and at least 18 years of age.
• Subjects must have a histologically confirmed (or documented), incurable B-cell hematologic malignancy that had progressed despite standard of care therapy and for which there was no alternative therapy of proven benefit or no effective standard therapy is available or tolerable.
• Measurable or evaluable Disease.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• Subject must have adequate organ function.

Exclusion Criteria:

• Has had prior chemotherapy, targeted therapy, immunotherapy or any other agents used as systemic treatment for cancer, within 14 days before first dosing.
• Had major surgery within 4 weeks before first dosing.
• Had undergone an autologous stem cell transplant within 100 days before first dosing.
• Evidence of severe or uncontrolled systemic diseases (e.g., unstable or uncompensated respiratory, hepatic, or renal disease).
• Known immediate or delayed hypersensitivity reaction or idiosyncrasy to drugs chemically related to the investigational product or excipients.
• Pregnant or breastfeeding women.
• Unwillingness or inability to follow the procedures outlined in the protocol.