[Efficacy of chemotherapy combined with bortezomib for two cases of relapsed/refractory acute lymphoblastic leukemia]

Bortezomib (BZM), a proteasome inhibitor, was recently reported to be effective against acute lymphoblastic leukemia (ALL). We report two cases of relapsed/refractory ALL, who were treated with BZM (1.3 mg/m2/dose, 2 doses/week for 2 weeks) in combination with vincristine, doxorubicin, dexamethasone, and L-asparaginase (L-ASP). The first patient was a 16-year-old girl who developed a bone marrow relapse 8 months after the initial diagnosis during consolidation chemotherapy. She received BZM-combined chemotherapy without L-ASP considering her previous history of an allergic reaction to L-ASP. The BZM-combined regimen was discontinued due to interstitial pneumonia development on day 13, and the interstitial pneumonia was successfully treated with steroid pulse therapy. Although her elevated serum LDH transiently normalized on day 16, blasts in peripheral blood did not disappear, and she died of leukemia without achieving remission. The second patient was a 17-year-old girl who developed a third bone marrow relapse after cord blood transplantation. She was given the same BZM combined regimen. Although the BZM-combined regimen was discontinued due to acute pancreatitis development on day 12, complete remission without platelet recovery was confirmed on day 62. Our experience suggests not only the effectiveness of BZM-combined chemotherapy but also the importance of controlling its toxicities when administered as a salvage therapy for advanced ALL patients.