To evaluate the efficacy and safety of chidamide combined with brentuximab vedotin regimen for CD30 positive PTCL patients who are unfit for chemotherapy.

This study will enroll CD30-positive peripheral T-cell lymphoma (PTCL) patients who are ineligible for conventional chemotherapy. Participants will receive induction therapy with 3 cycles of BvC regimen (brentuximab vedotin plus chidamide combination). Patients demonstrating disease progression (PD) or stable disease (SD) will be withdrawn from the study. Patients achieving partial remission(PR) or complete remission(CR) will receive stratification consolidation therapy as followings:

Cohort 1 (patients achieved CR): Receive 3 additional cycles of BvC consolidation

Cohort 2 (patients achieved PR): Receive 6 additional cycles of BvC consolidation

After consolidation therapy, responding patients (CR/PR) will receive chidamide maintenance therapy for ≥2 years

Inclusion Criteria:

1. Age ≥70 years or age < 70 years and unfit for chemotherapy, male or female not limited;
2. Patients must have the capacity to understand and willingly provide written informed consent;
3. ECOG score 0-3 points;
4. Expected lifespan>3 months;
5. Patients with CD30+ peripheral T-cell lymphoma (PTCL) confirmed by histopathology/cytology using the 2022 World Health Organization (WHO) Classification of Diseases;
6. Measurable lesions with a short diameter of ≥15mm defined by PET/CT.
7. R/R PTCL: patients with at least previous first-line treatment failure and no prior exposure to chidamide and brentuximab vedotin.
8. Patients are unfit for chemotherapy after evaluation or are not considered for chemotherapy for other reasons;
9. Any non-hematological toxicity, except hair loss, associated with prior treatment in patients with R/R disease, as per NCI CTCAE version 5.0, must be managed and resolved to at least grade 1;
10. Appropriate organ function: Cardiac function: ejection fraction ≥ 50%, asymptomatic arrhythmia; Liver function: alanine aminotransferase and aspartate aminotransferase ≤ 2 times the upper limit of normal, total bilirubin<2 times the upper limit of normal; Renal function: serum creatinine clearance rate ≥ 80 mL/min, creatinine<160 umol/l; Pulmonary function: Without oxygen inhalation, SPO2>90%, FEV1, FVC, and DLCO ≥ 50% predicted values;
11. Adequate bone marrow reserve is defined as: Hemoglobin ≥ 9g/dL, Platelet count ≥ 70 × 10 ^ 9/L, The absolute value of neutrophils is ≥ 1.0 × 10 ^ 9/L, If accompanied by bone marrow invasion, platelet count ≥ 50 × 10 ^ 9/L, absolute neutrophil count ≥ 0.75 × 10 ^ 9/L, The number of CD34+cells is ≥ 2.0 × 109/kg;
12. Subjects with fertility or potential for fertility must be willing to undergo contraception from the date of registration in this study until the study follow-up period;
13. Patients with good compliance.

Exclusion Criteria:

1. Patients with R/R disease previously used chidamide and brentuximab vedotin or received any other anti-tumor therapy within 4 weeks.
2. Patients enrolled in another clinical study within 4 weeks;
3. HIV infection and/or active hepatitis B or C;
4. Uncontrolled active infections;
5. Severe liver and kidney dysfunction (alanine aminotransferase, bilirubin, creatinine>3 times the upper limit of normal);
6. Existence of organic heart disease or severe arrhythmia, leading to clinical symptoms or abnormal heart function (NYHA functional class ≥ 2);
7. Simultaneously present other tumors that require treatment or intervention;
8. Previous or current history of vascular embolism;
9. Pregnant or lactating women;
10. In a state of severe immune suppression;
11. Other psychological conditions that hinder patients from participating in research or signing informed consent forms.
12. Patients are unlikely to complete all protocol study visits and procedures or do not meet the requirements for study participation.