This study is a single-arm, open-label, dose-escalating + dose-expansion clinical study, aiming to evaluate the safety and efficacy of targeting CD123 CAR-NK cell preparations in Relapsed/refractory acute myeloid leukemia (AML) or blastocytic plasmacytoid dendritic cell neoplasm (BPDCN). The pharmacokinetic characteristics of CAR-NK cell preparations for the treatment of patients with Relapsed/refractory acute myeloid leukemia or blastocytic plasmacytoid dendritic cell neoplasm were obtained and the recommended dose.

According to the different disease type, it is divided into two subgroups: AML and BPDCN. Each subgroup includes a dose exploration stage (Part A) and a dose expansion stage (Part B). 3 patients were explored, starting from the low-dose group, and in the dose expansion phase, the safety and efficacy were further verified according to the safe recommended dose obtained in the dose exploration phase.

Inclusion Criteria:

1. Gender is not limited, age 18-75 years old (including the threshold value);
2. The expression of CD123 in tumor cells was detected by flow cytometry.
3. Patients with relapsed/refractory AML or BPDCN diagnosed with CD123 positive: 1) AML: a. Recurrent: After complete response (CR), the recurrence of leukemia cells in peripheral blood or bone marrow original cells ≥5% (except for other reasons such as bone marrow regeneration after consolidation chemotherapy) or the occurrence of extramedullary leukemia cell infiltration; b. Refractory: refers to those who have failed to receive 2 courses of treatment with standard protocols; Patients recurrence within 12 months after CR with consolidation and intensive treatment; Recurrence after 12 months but failed to respond to conventional chemotherapy; 2 or more relapses; Extramedullary leukemia persists;

2) BPDCN: has failed to receive guidelines-recommended salvage therapy or is unable to tolerate current therapy, and has persistent or recurrent disease in any of the peripheral blood, bone marrow, lymph nodes, spleen, skin lesions, or other site lesions.

4. Expected survival time is more than 12 weeks;

5. ECOG 0-2 points (Appendix 2);

6. No serious mental disorders; The functions of important organs are basically normal:

1. Cardiac function: echocardiography indicated cardiac ejection fraction ≥50%, and no obvious abnormality was found in electrocardiogram;

2. Renal function: serum creatinine ≤2.0×ULN;

3. Liver function: ALT and AST ≤ 3.0×ULN;

4. Total bilirubin and alkaline phosphatase ≤ 2.0×ULN (Gilbert syndrome ≤ 3.0×ULN);

5. Blood oxygen saturation > 92%.

   7. The patient or his/her guardian agrees to participate in the clinical trial and signs the ICF, indicating that he/she understands the purpose and procedure of the clinical trial and is willing to participate in the study.

Exclusion Criteria:

1. Prior to screening, the following anti-tumor therapies were received: chemotherapy, targeted therapy, or other investigational drug treatment within 14 days or at least 5 half-lives (whichever is shorter), except in cases where disease progression has been confirmed after treatment;

2. had a cerebrovascular accident or seizure within 6 months before signing the ICF;

3. There is an active or uncontrolled infection that requires systemic treatment within 1 week prior to screening;

4. suffering from any of the following heart diseases:

   1. New York Heart Association (NYHA) Stage III or IV congestive heart failure;
   2. Had myocardial infarction or coronary artery bypass grafting (CABG) within ≤6 months before enrollment;
   3. A history of clinically significant ventricular arrhythmia, or unexplained syncope (other than those caused by vasovagal or dehydration);
   4. History of severe non-ischemic cardiomyopathy;

5. combined with active hepatitis B;

6. Combined with active autoimmune diseases, long-term immunosuppressive therapy is required;

7. have other malignancies, except for adequately treated cervical carcinoma in situ, basal cell or squamous cell skin cancer, local prostate cancer after radical surgery, and ductal carcinoma in situ after radical surgery;

8. Had received live attenuated vaccine within 4 weeks prior to screening;

9. Women who are pregnant or breastfeeding, and male or female subjects who plan to have a family within 1 year after receiving CAR T cell transfusion;

10. Circumstances deemed unsuitable for participation in the study by other researchers.