This is a single-arm, open-label, dose escalation, phase I study, aiming to evaluate the safety and efficacy of Autologous Humanized Anti-CD19 and Anti-CD20 Dual Specific Chimeric Antigen Receptor (CAR) T-cells in patient with relapsed or refractory diffuse B cell lymphoma.

CD19 CAR-T cell therapy has made breakthroughs in the treatment of B cell lymphoma and leukemia, but 30% of patients still have antigen escape, which may be related to variants in tumor cells and the expansion of CD19-negative tumor cells after treatment with CD19 CAR-T cells. CD19/CD20 bispecific CAR-T cell targeting multiple antigens can attack tumor cells while overcoming tumor antigen escape caused by a single target, maximizing efficacy and duration of treatment, and can also solve the problem of uneven distribution or low expression of single target on the tumor surface.

Inclusion Criteria:

1. The subject or her/his legally guardian(s) must sign the informed consent form approved by the Institutional Ethics Committee (IEC) prior to any screening procedures;

2. Subjects aged 18 years or older with relapsed or refractory DLBCL (primary mediastinal large B-cell lymphoma and transformed follicular lymphoma included), of which refractory is defined as:

   Have no response to the recent treatment including:

   • The best response to the treatment regimen is progressive disease (PD) ,or

   • stable disease (SD) which maintained less than 6 months after the last treatment, or

   • not suitable for autologous hematopoietic stem cell transplantation (ASCT), or ASCT refractory, including:

     • progressive disease after ASCT or relapse within 12 months (relapse must be confirmed by biopsy), or
     • If remedial treatment is given after ASCT, the subject must have no response or relapse after the last treatment.

3. Subjects who have previously received ≥2 lines treatment, and at least including:

   • Anti-CD20 monoclonal antibody(rituximab), unless the CD20 negative;
   • A chemotherapy regimen containing anthracyclines;
   • The DLBCL patients who transformed from follicular lymphoma must have previously received chemotherapy for follicular lymphoma and have developed chemotherapy-refractory diseases after transform to DLBCL.

4. Confirmation for either CD19 or CD20 positivity using immunohistochemistry or flow cytometry;

5. According to the initial evaluation, staging and response assessment of Hodgkin's and non-Hodgkin's lymphoma -the Lugano Classification (2014), there is at least one measurable lesion at baseline;

6. Life expectancy ≥12 weeks;

7. Eastern Cooperative Oncology Group (ECOG) performance status that is either 0 or 1 at screening;

8. Adequate organ function:

   Renal function defined as:

   • A serum creatinine of ≤1.5 × Upper Limit of Normal (ULN), or;
   • Estimated Glomerular Filtration Rate (eGFR) ≥60 ml/min/1.73m2；

   Liver function defined as:

   • ALT≤ 5 × Upper Limit of Normal (ULN) for age, and;
   • Total bilirubin ≤ 2.0 mg/dl with the exception of patients with Gilbert-Meulengracht syndrome; patients with Gilbert-Meulengracht syndrome may be included if their total bilirubin is ≤ 3.0 × ULN and direct bilirubin ≤ 1.5 × ULN.

   Must have a minimum level of pulmonary reserve defined as ≤ Grade 1 dyspnea and blood oxygen saturation > 91% on room air;

9. Hemodynamically stable and Left Ventricle Ejection Fraction (LVEF) ≥ 45% confirmed by echocardiogram or Multigated Radionuclide Angiography (MUGA);

10. Adequate bone marrow reserve without transfusions defined as:

    • Absolute neutrophil count (ANC) >1×10^9 /L；
    • Absolute lymphocyte count (ALC) ≥0.3×10^9 /L；
    • Platelets ≥50×10^9 /L;
    • Hemoglobin > 8.0 g/dl;

11. Must have an apheresis product of non-mobilized cells or peripheral blood harvested cells accepted for manufacturing

12. Subjects who use the following drugs should meet the following criteria:

    • Steroids: Therapeutic doses of steroids must be stopped 2 weeks prior to A-02 infusion. However, the following physiological replacement doses of steroids are allowed: < 6 - 12 mg/m^2/day hydrocortisone or equivalent;
    • Immunosuppression: Any immunosuppressive medication must be stopped ≥ 4 weeks prior to sign the informed consent form;
    • Anti-proliferative therapy other than pretreatment chemotherapy within 2 weeks of A-02 infusion;
    • CD20 antibody-related treatment must be discontinued within 4 weeks of A-02 infusion or 5 half-lives (whichever is longer);
    • CNS disease prophylaxis must be stopped > 1 week prior to A-02 infusion (e.g. intrathecal methotrexate);

13. The investigator judged that the subject recovered from the toxicity of the previous anti-tumor treatment to grade 1 or below (except for special grade 2 or below toxicity that cannot be recovered in a short period of time, such as hair loss), suitable for pretreatment. Chemotherapy and treatment of CAR-T cells;

14. Women of child-bearing potential and all male subjects must agree to use highly effective methods of contraception for at least 12 months following A-02 infusion and until CAR-T cells are no longer present by PCR on two consecutive tests.

Exclusion Criteria:

1. Prior treatment with any cell therapy before signing the informed consent form, including CAR-T therapy;

2. Subjects with detectable cerebrospinal fluid malignant cells or brain metastases, or with a history of central nervous system (CNS) lymphoma or primary CNS lymphoma;

3. Subjects with testicular invasion, including those who have had testicular resection;

4. Subjects with current or previous history of central nervous system disease, such as seizures, cerebral ischemia/hemorrhage, dementia, cerebellar disease, or any autoimmune disease involving the central nervous system;

5. Subjects who have previously received allogeneic hematopoietic stem cell transplantation (HSCT); or suitable and consenting to Autologous hematopoietic stem cell transplantation (ASCT);

6. Chemotherapy other than lymphodepleting chemotherapy within 2 weeks of A-02 infusion;

7. Patients on oral anticoagulation therapy within 1 week of A-02 infusion;

8. Prior radiation therapy within 2 weeks of A-02 infusion;

9. Investigational medicinal product within the last 30 days prior to sign the informed consent form;

10. Subjects with active hepatitis B（defined as hepatitis B surface antigen positive, or hepatitis B core antibody positive with hepatitis B virus DNA detection value > 1000 copies/ml）or hepatitis C (HCV RNA positive)

11. Subjects positive for HIV antibody or treponema pallidum antibody;

12. Uncontrolled acute life threatening bacterial, viral or fungal infection (e.g. blood culture positive ≤ 72 hours prior to A-02 infusion)

13. Unstable angina and/or myocardial infarction within 6 months prior to sign the informed consent form;

14. Previous or concurrent malignancy with the following exceptions:

    • Adequately treated basal cell or squamous cell carcinoma (adequate wound healing is required prior to sign the informed consent form);
    • In situ carcinoma of the cervix or breast, treated curatively and without evidence of recurrence for at least 3 years prior to sign the informed consent form;
    • A primary malignancy which has been completely resected and in complete remission for ≥ 5 years;

15. Pregnant or nursing women (women of childbearing age were tested positive for pregnancy during screening period);

16. Cardiac arrhythmia not controlled with medical management;

17. Subjects with active neurological auto immune or inflammatory disorders (e.g. Guillain Barre Syndrome, Amyotrophic Lateral Sclerosis);

18. Other conditions that the investigator thinks he/she should not be included in this clinical trial, such as poor compliance.