Efficacy of rituximab and cladribine in patients with chronic lymphocytic leukemia and feasibility of stem cell mobilization: a prospective multicenter phase II trial (protocol SAKK 34/02)

Abstract

This phase II trial investigated rituximab and cladribine in chronic lymphocytic leukemia. Four induction cycles, comprising cladribine (0.1 mg/kg/day days 1–5, cycles 1–4) and rituximab (375 mg/m² day 1, cycles 2–4), were given every 28 days. Stem cell mobilization (rituximab 375 mg/m² days 1 and 8; cyclophosphamide 4 g/m² day 2; and granulocyte colony-stimulating factor 10 µg/kg/day, from day 4) was performed in responders. Of 42 patients, nine achieved complete remission (CR), 15 very good partial remission, and two nodular partial remission (overall response rate 62%). Stem cell mobilization and harvesting (≥2×10⁶ stem cells/kg body weight) were successful in 12 of 20 patients. Rituximab infusion-related adverse events were moderate. The main grade 3/4 adverse events during induction were neutropenia and lymphocytopenia. Rituximab plus cladribine was effective; however, the CR rate was modest and stem cell harvest was impaired in a large number of responding patients.

Keywords:

• CLL
• rituximab
• cladribine
• phase II study

Acknowledgements

We would like to thank Prof. Dr. M. F. Fey for the careful reading of and the precise and helpful comments on the manuscript. We also thank Pierluigi Ballabeni for his statistical support at the early stage.

Declaration of interest: This trial was supported by the Staatssekretariat für Bildung und Forschung (SBF), Oncosuisse (grant number OCS 01274-08-2002), Roche Pharma (Schweiz) AG, Reinach, and Lipomed AG, Arlesheim.