TCL-445: Case of T-Cell Prolymphocytic Leukemia Successfully Treated with Fludarabine, Mitoxantrone, and Cyclophosphamide

Context T-cell prolymphocytic leukemia (T-PLL) is an extremely rare mature T-cell neoplasm associated with an aggressive clinical course, poor response to conventional chemotherapy, and a dismal prognosis. Current therapeutic strategies conventionally employ the anti-CD52 antibody alemtuzumab as the most active agent. Alemtuzumab, originally marketed for use in cancer (Mabcampath®), is currently licensed and formulated for the treatment of relapsing multiple sclerosis (Lemtrada®), causing a lack of drug availability, with potentially grave consequences for T-PLL patients’ prognosis. Design We present the case of a 68-year-old male patient diagnosed with T-PLL in December 2020, who underwent four cycles of fludarabine 25 mg/m2, mitoxantrone 8 mg/m2, and cyclophosphamide 200 mg/m2, and achieved complete remission (CR), according to the criteria established by the T-PLL International Study Group. Results A 68-year-old Caucasian male presented to our center with fatigue and weakness for several months and a history of persistent, progressive lymphocytosis for the past 18 months. A computed tomography scan revealed bilateral cervical, axillary, and intra-abdominal lymph nodes, measuring approximately 3 cm each; an enlarged spleen of 180 mm in length; and mild hepatomegaly, measuring 177 mm on the midclavicular line. Laboratory studies revealed leukocytosis (282 × 109/L) and an absolute lymphocyte count of 255 × 109/L, with no anemia or thrombocytopenia. The metabolic profile was normal, except for an elevated lactate dehydrogenase of 974 U/L. The bone marrow aspirate showed 86%–88% polymorphic lymphoid cells, while the flow cytometry analysis indicated T cells positive for CD2 and surface and cytoplasmic CD3, CD5, and CD7, 70% of which were CD4+CD8+, and 30% CD4+. The core biopsy revealed a markedly hypercellular marrow (80%), with a lymphoid infiltrate made up of small/medium-sized cells, some with cerebriform nuclei, some with prominent nucleoli, with weakly positive immunohistochemistry staining for CD52. Conclusions The patient presented in this case study was treated with conventional chemotherapy alone and achieved CR of T-PLL, maintaining the treatment response to date (3 months after completion of the therapy). Despite this, alemtuzumab remains a crucial element in the arsenal of treatment for T-PLL, and its lack of availability poses a serious challenge for clinicians.