Fludarabine, idarubicin, and cytarabine regimen together with TKI followed by haploidentical hematopoietic stem cell transplantation, a success for relapsed Ph+ acute lymphoblastic leukemia

Acute lymphoblastic leukemia ( ALL) is a heterogeneous malignant clonal hematological disease. Combined chemotherapy for adult ALLcan achieve a high remission rate similar to that for the pediatric ALL1, 2. For Philadelphia chromosome‐positive (Ph+) ALL, the combination of chemotherapy and tyrosine kinase (TKI) therapy enhanced the rate of complete remission (CR) and prolonged the CR time, but failed to extend the overall survival (OS) 3. Relapse after chemotherapy plus transplantation is the main cause of death in adult ALLpatients 4. The risk classification of ALLreflects the disease's prognosis and guides the treatment of pediatric ALL. The treatment of adult ALLbased on the risk classification failed to achieve better therapeutic efficacy, and allogeneic hematopoietic stem cell transplantation (Allo‐HSCT) becomes the preferred treatment for adult ALLin the standard‐risk group 5. The relapsed ALLleads to high mortality (~90%) of Ph+ ALL6. The current focus of studies includes postrelapse reinduction chemotherapy, intensified treatment after remission, and optimization of allo‐HSCT. The selection of salvage chemotherapy for relapsed adult ALLis highly correlated with the timing of the relapse. For the relapses within 6 months after remission, the original induction chemotherapycan be considered. Alternatively, other programs or clinical trials should be applied 6. Currently, the regimen using an increased dose of multidrug chemotherapy combined with targeted therapy is generally adopted. Treatment based on the detection and elimination of minimal residual disease(MRD) is an ideal treatment strategy after remission. Allo‐HSCT can effectively eliminate MRD by pretreatment with high‐intensity chemotherapy followed by graft‐versus‐leukemia (GVL) effects. This approach represents the only clinically relevant treatment for the clinical cure of relapsed adult ALL7. Here, we report a case of secondary adult Ph+ ALLwith osteosarcoma patient who was treated with a novel TKI‐based FLAI regimen including TKI, Fludarabine(Flu), Idarubicin(IDA), and Cytarabine(Ara‐c) reinduction. After the successful induction of remission, the patient was administered with an incremental dose of FLAI to intensify and consolidate the treatment efficacy. Subsequently, the patient underwent haploidentical allo‐HSCT and TKI was stopped after transplantation. During this period, septicemia, fungal infections, and second‐degree skin rejection occurred. The post‐transplantation MRD was negative. The patient is currently in a hematologic and molecular remission without relapse in leptomeningesor the extramedullary site. Results from this case suggest that the regimen could be an option for the patients with relapsed adult Ph+ ALL.