From the Guidelines
The initial treatment recommendation for hairy cell leukemia is a purine analog, with cladribine (2-CdA) being the preferred first-line agent, as it induces durable and unmaintained response in 87%–100% patients, including complete response in 85%–91%, after a single course of therapy 1.
Key Considerations
- Cladribine is typically administered as a single course of 0.1 mg/kg/day by continuous intravenous infusion for 7 days, or alternatively as a subcutaneous injection of the same dose for 5-7 days 1.
- Pentostatin is an alternative purine analog that can be used at a dose of 4 mg/m² intravenously every other week for 3-6 months 1.
- Treatment is indicated when patients develop significant cytopenias (hemoglobin <10 g/dL, platelets <100,000/μL, absolute neutrophil count <1,000/μL), recurrent infections, symptomatic splenomegaly, or constitutional symptoms 1.
Patient Assessment
- Before initiating treatment, patients should have baseline blood counts, bone marrow examination, and assessment for infections, as hairy cell leukemia patients are susceptible to infections due to neutropenia and monocytopenia 1.
- Prophylactic antibiotics may be necessary during treatment 1.
Watch-and-Wait Approach
- Not all patients require immediate treatment; asymptomatic patients with adequate blood counts can be monitored with a watch-and-wait approach 1.
- Clinical judgement is required in the decision to initiate therapy, because not all patients with newly diagnosed HCL will require immediate treatment 1.
From the FDA Drug Label
At initiation of treatment, most patients in the clinical studies had hematologic impairment as a manifestation of active Hairy Cell Leukemia. Following treatment with cladribine, further hematologic impairment occurred before recovery of peripheral blood counts began The myelosuppressive effects of cladribine were most notable during the first month following treatment Careful hematologic monitoring, especially during the first 4 to 8 weeks after treatment with cladribine, is recommended
The initial treatment recommendation for hairy cell leukemia is cladribine.
- The recommended treatment regimen is 0.09 mg/kg/day for 7 consecutive days by continuous intravenous infusion.
- Careful hematologic monitoring is recommended, especially during the first 4 to 8 weeks after treatment with cladribine.
- Patients should be monitored for signs of myelosuppression, including neutropenia, anemia, and thrombocytopenia 2.
From the Research
Hairy Cell Leukemia Treatment
- Hairy cell leukemia (HCL) is an uncommon, indolent, chronic B-cell lymphoproliferative disorder involving the marrow and spleen 3.
- The initial treatment recommendation for hairy cell leukemia includes cladribine, which is a purine nucleoside analogue 4.
Cladribine Treatment
- Cladribine is administered at a dose of 0.1 mg/kg/d for a total of 7 days as a continuous intravenous infusion 3, 5.
- A single course of cladribine can induce complete remission (CR) in the majority of patients, with an overall response rate of 100% 3, 5.
- The median first-response duration for all responders is around 98 months, and the overall survival rate is around 97% at 108 months 3.
Combination Therapy
- Recent studies have explored the use of cladribine in combination with rituximab, which can enhance the achievement of minimal residual disease (MRD)-free complete remission 6.
- Concurrent rituximab with cladribine has been shown to lead to higher rates of MRD-free CR compared to delayed rituximab or cladribine monotherapy 6.