Bolus administration of cladribine in the treatment of Waldenstrom macroglobulinaemia

This phase II clinical trial evaluated bolus cladribine as a single agent i n Waldenstrom macroglobulinaemia (WM). Cladribine was administered to 20 patients at a dose of 0.12, mg/kg/d by 2 h intravenous infusion for 5 consecutive days at monthly intervals for thre e courses, Partially responding patients were continued on therapy until ma ximal response and/or prohibitive toxicity, to a maximum of eight courses. Complete responders were treated with one additional course of cladribine. After a median of three courses of cladribine, all 20 patients were evaluab le one achieved a complete response (CR) (5%) and 10 achieved a partial res ponse (PR) (50%). The median duration of response follow-up was 28 months ( range 1-37 months). Four of 7 (57%) untreated and 7/13 (54%) previously tre ated patients responded. The major toxicity encountered was myelosuppressio n with 60% of patients demonstrating grade 3 or 4 neutropenia, Non-haematol ogical toxicities included two patients with herpes zoster and two patients with non-melanoma skin cancers. At a median follow-up duration of 20 month s, 17 patients remain alive and three have died. We confirm that bolus cladribine is an effective and safe method of drug de livery in WM patients. Recommendations regarding the equivalence of the con tinuous infusion and bolus methods in untreated patients requires further s tudy Bolus cladribine is more convenient and less costly than infusional cl adribine since it obviates the need for central catheters and infusional de vices.