Hairy-cell leukemia is a rare and indolent lymphoid disorder, representing 2% of all cases of
lymphoid leukemias. Treatment of hairy-cell leukemia relies mainly on the purine analogs,
cladribine and pentostatin, which have shown similar efficacy and constitute the gold
standard of care either as front-line therapy or for relapsed patients.
However, despite the remarkable response rates obtained with purine analogs therapy, some
patients will eventually relapse and the efficacy of these agents seems to decrease at each
line of treatment. The addition of new molecules to purine analogs may improve the response
rates and prevent relapse.
Rituximab is a chimeric IgG1 kappa-type monoclonal antibody directed against the CD20
molecule. It was first used in relapsed patients with hairy-cell leukemia more than 10 years
ago and several series of patients treated with rituximab as monotherapy were published in
the following decade, reporting response rates ranging from 25% to 80%.