IBCL-629 Outcome of Hairy Cell Leukemia Treated With Cladribine: A 15-Year Single-Center Retrospective Study

• Published in: Clinical lymphoma, myeloma and leukemia myeloma and leukemia, 2024-09, Vol.24, p.S505-S506
• Main Authors: Da'na, Waleed, Yaseen, Abeer, Hamo, Khair, Al rabi, Kamal, Shahin, Omar, Abdel Rahman, Zaid, Marei, Lina, Halahleh, Khalid, Khader, Renad, Ma'koseh, Mohammad
• Format: Article
• Language: English
• Subjects: cladribine; hairy cell leukemia; IBCL; splenomegaly
• ISSN: 2152-2650
• DOI: 10.1016/S2152-2650(24)01580-5

Hairy cell leukemia (HCL) is a rare indolent B-cell lymphoproliferative disorder that typically responds well to purine analogues. However, relapse is common. To evaluate the outcome of patients with HCL treated with cladribine at our center. We retrospectively reviewed the medical records of adult patients (aged >18 years) diagnosed with HCL and treated with cladribine from 2006 until 2022. Responses were defined according to the standard criteria. Survival outcomes were plotted using a Kaplan-Meier method and compared using a log-rank test. Thirty-seven patients were included, with a median age of 42 years (range, 29-76). The majority (83%) were male. Thirty-five patients (94.6%) had classical HCL, and 2 (5.4%) had the variant type. The most common presenting symptoms were bone marrow failure (23 patients, 62.1%), fatigue (14 patients, 37.8%), and weight loss (7 patients, 18.9%). Additionally, 14 patients (37.8%) had massive splenomegaly. Following the first dose of cladribine, 21 patients (56.8%) achieved a complete response, 14 (37.8%) had a partial response, and 2 (5.4%) died before response evaluation. Neutropenic fever complicated the treatment in 24 patients (64.8%). After a median follow-up of 74 months, median progression-free survival (PFS) was 103 months (95% CI, 43-164) with a 5-year PFS of 61%. The median overall survival (OS) was not reached; 5-year OS rate was 83.1%. Ten patients (27%) relapsed after a median of 48.6 months (range, 17-119), all requiring treatment. Treatments for relapse included cladribine (6 patients), cladribine with rituximab (2 patients), rituximab (1 patient), and pentostatin and rituximab (1 patient). All patients responded to treatment. One patient experienced a second relapse, was treated with rituximab, and subsequently died from sepsis. Our study supports the long-term efficacy and safety of cladribine as a front-line treatment of HCL. Although relapses are not uncommon, they can be effectively managed with cladribine, rituximab, or pentostatin.