A 3-decade multicenter European experience with cladribine as upfront treatment in 384 patients with hairy cell leukemia

Abstract

Cladribine is regarded as the first treatment of choice of symptomatic hairy cell leukemia (HCL): it provides high rates of response and very long duration of remission in some cases. Disease-specific patients records have been reviewed at four European centers of excellence; all patients with HCL requiring treatment who received frontline cladribine have been extrapolated. Responses have been classified according to Consensus Resolution Criteria. Three hundred and eighty-four patients have been diagnosed and followed between 1969 and 2018; all received frontline cladribine (subcutaneously or intravenously). A complete response was obtained in 72% of cases and a partial response in 22%. A continuous complete response was documented in 20% of patients at a median follow-up period of 8.5 years (range, 1-22 years). Median overall survival was reached at 25 years. Median progression-free survival was 13 years and median disease-free survival was 11 years. Cladribine is effective as frontline treatment of HCL and may determine deep disease control in a significant proportion of cases, given that more than 50% of treated patients require no further therapy. Good quality responses may be maintained for more than 20 years in up to 35% of patients.

Measurable residual disease in hairy cell leukemia: Technical considerations and clinical significance

“…Guerrini et al. used the ddPCR in retrospective study of 47 HCL patients including 27 with classic HCL, two with HCLv and 18 with splenic marginal zone lymphoma (SMZL) ( 12 , 39 ). The study found the sensitivity of dd-PCR to be about half a logarithm superior to QT-PCR (5 × 10 -5 vs. 2.5 × 10 -4 ).…”

“…In a similar study, Broccoli et al. measured BRAF V600E burden by ddPCR in PB and/or BM in 35 HCL patients at diagnosis, relapse, and CR ( 12 ). In PB, the mean fractional abundance values were 12.26% at diagnosis, 16.52% at relapse and 0.02% at CR, with the corresponding values in BM being 23.51%, 13.96%, and 0.26%.…”

“…A recent multicenter analysis in Europe confirmed that 2-CdA used as frontline treatment in HCL patients permits disease control in a significant proportion of cases, given that more than 50% of treated patients require no further therapy. Good quality responses may be maintained for more than 20 years in up to 35% of patients ( 12 ).…”

Hairy cell leukemia 2024: Update on diagnosis, risk‐stratification, and treatment—Annual updates in hematological malignancies

“…Only five patients received R more than once and the ORR decreases with the number of lines. 147 In case of response to first-line treatment lasting less than 2 to 5 years, or for primary refractory HCL, we do not recommend using CDA again. The most promising and targeted treatments include BRAF inhibitors (BRAFi), MEK inhibitors (MEKi), and recombinant immunoconjugates targeting CD22.…”

Hairy Cell Leukemia

“…The purine nucleoside analogs cladribine (2-chlorodeoxyadenosine, 2-CdA) and pentostatin (deoxycoformycin, DCF), remain the standard first-line treatment for HCL and their design is still recognized as one of the greatest achievements in cancer therapy (Table 1) (31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43).…”