This is a Phase 1, open-label, multi-center study to evaluate the safety of JMT601 in the treatment of relapsed or refractory CD20-positive B-cell non-Hodgkin lymphoma and to determine the recommended dose for Phase 2 studies (RP2D). Study consists of 2 parts. The first part is a dose-escalation part using a 3+3 design with up to 6 dose(0.3 mg/kg, 1 mg/kg, 3 mg/kg, 6 mg/kg, 12 mg/kg and 20 mg/kg) escalation cohorts at increasing levels. The second part is a dose-expansion part at R2PD dose to assess preliminary efficacy of JMT601.

Key Inclusion Criteria:

• Participants diagnosed with CD20-positive B-cell non-Hodgkin lymphoma confirmed by histopathology and/or cell biology who have previously received 2 or more lines of therapy

• Eastern Cooperative Oncology Group (ECOG) physical state score: 0-2

• Participants must have at least one evaluable or measurable lesion according to Lugano 2014 criteria.

• Expected survival of at least 3 months;

• Suitable organ and hematopoietic function:

  1. The absolute count of neutrophil (ANC) ≥1.0×109/L;
  2. Platelets ≥75×10^9/L (if bone marrow invasion doesn't exist)/≥50.0×10^9/L (if bone marrow invasion exists);
  3. Hemoglobin ≥90 g/L;
  4. Serum creatinine ≤1.5×ULN or creatinine clearance ≥50 mL/min;
  5. Total bilirubin ≤1.5×ULN, alanine aminotransferase ≤2.5×ULN, aspartate aminotransferase ≤2.5×ULN; Subjects with liver lesion: TBIL≤3×ULN, ALT≤5×ULN, AST≤5×ULN;
  6. International Standardized ratio and activated partial thromboplastin time ≤1.5 × ULN;

Key Exclusion Criteria:

• Confirmed central nervous system (CNS) lymphoma.
• Subjects who have received allogeneic hematopoietic stem cell transplantation (HSCT) or other organ transplantation
• Those who have previously received targeted CD47 or signal regulatory protein α (SIRRP α) therapy.
• Previous or current hemolytic anemia, Evans syndrome, arteritis;
• Subjects with previous or current other malignant tumors;
• Previous or current history of active autoimmune diseases;
• Subjects who had undergone major surgery within 4 weeks prior to initial dosing or expected to have major surgery during the study period;
• HIV infection, active syphilis, hepatitis B surface antigen (HBsAg) positive and HBV-DNA higher than the lower limit or 1000 copies /ml(500 IU/ml), HCV antibody positive and HCV-RNA higher than the lower limit or 1000 copies /ml