Relapsed or refractory acute lymphoblastic leukemia (ALL) in adults has a low cure rate, with only 10 to 20% of patients in second complete remission (CR) being cured after allogeneic bone marrow transplantation from an HLA-identical sibling[1]. The goal of treatment is to achieve remission and consolidate it with allogeneic hematopoietic stem cell transplantation (allo-HSCT), which brings a significant benefit for survival[2][5]. Traditional chemotherapy has limited success and high toxicity, with the probability of remission decreasing with each relapse from 40% for first salvage to 21% and 11% for subsequent ones [3]. New drugs such as blinatumomab achieve CR/CRh in 43% of patients, with a median relapse-free time of 5.9 to 6.7 months and MRD negativity in 88% of respondents[4][6]. Inotuzumab ozogamicin and CAR-T cells (eg, tisagenlecleucel with 81% remission and median event-free time of 24 months) outperform chemotherapy with lower toxicity and higher transplant rates[2][3][5]. As an anthracycline, mitoxantrone improved overall survival in children compared to idarubicin and became the standard[2]. Most patients require allo-HSCT for sustained remission, although some achieve long-lasting remission without it[5]. Advances include bispecific T-cell engagers, antibody drugs, and tyrosine kinase inhibitors[2][8].