Methotrexate, Hydrocortisone, Vincristine, Sobuzoxane, and Etoposide Is an Effective Option for Relapsed T-cell Prolymphocytic Leukemia with Loss of CD52 Expression after Retreatment with Alemtuzumab.

T-cell prolymphocytic leukemia (T-PLL) is a rare and highly aggressive mature T-cell neoplasm. Although the response rate to alemtuzumab, an anti-CD52 antibody, is high, it is difficult to cure the disease with this agent alone. Therefore, hematopoietic stem cell transplantation is recommended for eligible patients. However, there are few effective salvage therapy options for patients ineligible for hematopoietic stem cell transplantation. In this study, we report the case of an elderly patient with relapsed or refractory T-PLL who underwent salvage therapy with methotrexate, hydrocortisone, vincristine, sobuzoxane, and etoposide (MTX-HOPE). The patient was an 85-year-old man. He was administered alemtuzumab twice (at the time of initial treatment and relapse) and cyclophosphamide, vincristine, and hydrocortisone chemotherapy. Furthermore, novel therapeutic drugs (venetoclax and tofacitinib) were administered based on previous case reports. However, the patient was resistant to all treatments, and the tumor cells lost CD52 expression. We administered MTX-HOPE, and the patient survived for approximately 8 months. Although red blood transfusions were necessary because of disease progression, no adverse events were observed because of treatment, and the patient was able to maintain activities of daily living until immediately before death. MTX-HOPE is a combination of classical chemotherapy agents originally developed for palliative chemotherapy in frail patients with refractory lymphoma. MTX-HOPE has been reported to be effective against T-cell tumors. Severe nonhematologic adverse events are rarely reported; however, bone marrow suppression is commonly observed. Grade 3-4 neutropenia has been documented in approximately half of the patients. Therefore, patients should be closely monitored, particularly at the onset of therapy. Consideration should be given to suspending treatment, adjusting the administration interval, or administering G-CSF if necessary. The treatment interval can be appropriately adjusted, making it a valuable treatment option for refractory T-PLL.