[Clinical analysis of 24 patients of hairy cell leukemia treated by cladribine]

Objective: To investigate the curative effect of hairy cell leukemia by clatabine. Methods: The clinical data of 24 patients with hairy cell leukemia treated by cladribine from November 2006 to October 2017 were analyzed retrospectively, then the curative effect and adverse drug reaction were analyzed. Results: ① A total of 24 patients including 22 male and 2 female, and the median age was 49.5 years (range 33 to 76) at diagnosis. There were 20 patients with of splenomegaly (4 patients with mild splenomegaly, 4 moderate splenomegaly, and 12 massive splenomegaly), 3 patients with enlargement of lymph nodes, and 1 patients who had undergone splenectomy. Five patients were pancytopenia, 15 were cytopenia in 2 lineages, and 4 patients were cytopenia only in one lineage. The median ratio of HCL cells detected by flow cytometry in bone marrow was 21.79% (0.69%-68.96%). BRAF mutation was detected in 15 patients by first generation or next generation sequencing technology. ② Among 24 patients, 20 were treated with cladribine alone (one course in 19 patients, 2 courses in 1 patient), and 4 patients were treated with cladribine combined with rituximab (one course in 3 patients, 2 courses in 1 patient). Excepting 5 patients whose follow-up time was not reaching 6 months, 19 patients were evaluated for efficacy in 6-12 months after treatment: 9 patients obtained CR, 9 obtained unconfirmed CR (Cru), the other 1 obtained PR, the CR/CRu rate was 94.7%, the overall response rate (ORR) was 100.0%. ③ All the 24 patients appeared 2-4 grade hematological adverse reactions after cladribine treatment, which were mainly grade 3/4 neutropenia (66.67%) and grade 3/4 thrombocytopenia (29.2%). All the adverse reactions were controlled or recovered spontaneously. ④ After the median follow-up time of 15 (3-133) months, no progression, recurrence or death occurred in the patients. Both median OS and PFS were not reached. Conclusion: This study suggests that treatment of HCL with cladribine has high response rate, controllable adverse reactions and the good prognosis.