Inpharma 1502 - 27 Aug 2005

BL 22 active in hairy cell leukaemiaThe immunotoxin BL 22* [GCR 3888], an anti-CD22

Fv fragment fused to truncated Pseudomonas exotoxin,is active in hairy cell leukaemia (HCL), according toresults from a phase I trial.

46 pretreated patients with HCL (n = 31), chroniclymphocytic leukaemia (CLL; 11) or non-Hodgkin’slymphoma (NHL) received BL 22 at a dose of 3–50 µg/kgevery other day for three doses; patients were eligiblefor additional treatment cycles at 3–6 week intervals ifthey did not have progressive disease or highneutralising antibody levels.

Among the patients with HCL, complete and partialremissions were achieved in 61% and 19%, respectively.All the patients who responded to treatmentexperienced improvement in cytopenias; completeresolution of cytopenias occurred in all those in whoexperienced a complete remission (CR) and in two of sixpatients who experienced a partial response. A CR wasobserved in 86% of the patients who received BL 22 at adose of ≥ 40 µg/kg. The median duration of CR was36 months; eight patients remained in CR for> 45 months.

None of the patients with CLL or NHL experienced CR.One patient with CLL experienced eradication of> 99.9% of circulating CLL cells and an improvement incytopenias, but due to the presence of an abdominalmass, this patient was only classified as having amarginal response.

During the first cycle, only grade 1–2 reversibletoxicities were observed; during subsequent cycles, themost common adverse events were hypoalbuminaemia,elevations of AST and ALT levels, fatigue and oedema.* Genencor International; phase II for leukaemia in the US

Kreitman RJ, et al. Phase I trial of recombinant immunotoxin RFB4 (dsFv)-PE38(BL22) in patients with B-cell malignancies. Journal of Clinical Oncology 23:6719-6729, No. 27, 20 Sep 2005 801017245

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Inpharma 27 Aug 2005 No. 15021173-8324/10/1502-0001/$14.95 Adis © 2010 Springer International Publishing AG. All rights reserved