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%.

Aims of the study were :

• to assess the overall efficacy of rituximab in a cohort of unselected patients with hairy-cell leukemia
• to identify factors associated to treatment response, to duration of treatment response and to patient survival in a cohort of unselected patients with hairy-cell leukemia

Inclusion Criteria:

• patients with hairy-cell leukemia diagnosed between July 2002 and September 2012
• patients had received at least 3 subsequent injections of rituximab
• aged > 18 years

Patients with hairy-cell leukemia.