Background: B-cell prolymphocytic leukemia (B-PLL) is a rare mature B-cell tumor with an aggressive clinical course and poor prognosis. It is characterized by prominent splenomegaly and prolymphocytes exceeding 55% of the lymphoid cells in the blood. Purine analog-based chemo-immunotherapy is the first-line therapy for B-PLL. Owing to its rarity, there are few reports on the efficacy of bendamustine and rituximab (BR) regimen. Our study presents three cases of BR being effective in the treatment of B-PLL and provides experience for clinical treatment. Case Description: This report describes the cases of three male patients (median age: 66 years old) who initially presented with abdominal discomfort. Physical examinations and imaging revealed splenomegaly, while a peripheral blood (PB) smear revealed a prolymphocyte count exceeding 70% of the lymphoid cells. Therefore, the three patients were diagnosed with B-PLL. Further molecular detection showed that they harbored P53 abnormalities (17p deletion/TP53 mutation) associated with resistance to conventional chemotherapies. In addition, one of the patients had a highly complex karyotype and multiple gene mutations. All patients underwent four cycles of BR, and two of them received two further cycles of rituximab monotherapy. Ultimately, the patients achieved a complete response (CR) that lasted for 25, 33, and 34 months, respectively, with a median follow-up time of 34 months. The adverse events of the BR mainly included a grade 3 haematological toxicities. Also, the treatment was well-tolerated. Conclusions: This case series suggests that BR regimen is promising for bringing deep remission to patients with B-PLL. Prospective trials are still required for further elucidation.
