The goal of this phase 2 clinical trial is to test the efficacy of decitabine and venetoclax combination chemotherapy in relapsed or refractory adult T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma.

This study use a modified regimen of decitabine and venetoclax.

Our study is conducted in collaboration with Korean adult acute lymphoblastic leukemia working party (KALLWP) and consortium for improving survival of lymphoma (CISL). This study recruits adult patients with R/R T-ALL/LBL and treated with 7-day decitabine plus 3 weeks of venetoclax up to 12 cycles.

Inclusion Criteria:

• Adults aged 19 years or older but less than 80 years
• Eastern Cooperative Oncology Group Performance Score (ECOG PS) ≤ 2
• Confirmed diagnosis of T-cell lymphoblastic leukemia/lymphoma according to the 2016 World Health Organization criteria, with relapse or failure to achieve complete remission despite induction chemotherapy
• Patients with peripheral blood leukocytes <50,000/uL (reducing white blood cell count through hydroxyurea or leukapheresis prior to trial enrollment is allowed)
• At the time of screening, a calculated glomerular filtration rate (GFR) ≥ 30 mL/min according to the Cockcroft-Gault formulas, or creatinine ≤ 1.4, total bilirubin ≤ 3.0 mg/dL, and AST and ALT < x5 upper limit of normal (ULN) (however, if bilirubin elevation is due to Gilbert's syndrome or liver enzyme elevation is due to infiltration of leukemia/lymphoma, enrollment may be allowed even if the above conditions are exceeded)
• Individuals who agree to the following contraceptive measures for a period of 3 months during treatment and for 3 months after completion:

Exclusion Criteria:

• Individuals in complete remission with previous treatment, if relapse or resistance is not confirmed by bone marrow examination or imaging/tissue examination.
• Individuals who previously received venetoclax + decitabine treatment for T-lymphoblastic leukemia/lymphoma (participants who received venetoclax + decitabine treatment for a different type of cancer [e.g., acute myeloid leukemia] and have elapsed more than 1 year since the last treatment are allowed).
• Pregnant or breastfeeding individuals.
• Individuals who received systemic anticancer chemotherapy or participated in a clinical trial treatment within the past 2 weeks.
• Individuals with active leukemia involving the central nervous system.
• Individuals with a cancer type other than T-lymphoblastic leukemia/lymphoma that requires current active treatment (participants with a cancer type that has already been cured or is in a slow-progressing state without treatment, as determined by surgery/radiation/chemotherapy, may participate under the consultation of the clinical trial investigator).
• Individuals with active human immunodeficiency virus (HIV) infection, hepatitis B/hepatitis C infection (participants without evidence of viral particles through PCR testing may be enrolled with the consent of an infectious disease specialist or hepatologist).
• Uncontrolled bleeding.
• Uncontrolled infection (bacterial, fungal, viral).
• Uncontrolled mental illness.
• Individuals who do not understand the informed consent or have difficulty in adequate communication, making them inappropriate for participation in the clinical trial.
• Cases where the investigator judges that patient evaluation may be hindered or participation in the clinical trial is not appropriate.
• Individuals who have a negative attitude towards participating in the clinical trial or who are unwilling to comply with the treatment and specimen collection schedule specified in the study protocol.