Source
Department of Leukemia, The University of Texas M. D. Anderson Cancer Center, Houston, Texas 77030, USA. sverstov@mdanderson.org
Abstract
PURPOSE:
Patients with hypereosinophilic syndrome (HES) or chronic eosinophilic leukemia (CEL) that are refractory to standard therapies are difficult to manage and have significantly shortened life expectancy.
EXPERIMENTAL DESIGN:
CD52 is a surface glycoprotein highly expressed on eosinophils. We treated 11 patients with advanced HES/CEL with alemtuzumab, a humanized anti-CD52 monoclonal antibody. Alemtuzumab was administered, in general, first in escalating doses (5, 10, 30 mg i.v. on days 1-3), then at the tolerated dose thrice per week for a total of 12 doses. Patients with complete hematologic response (CHR; normal percent and absolute eosinophil count) were allowed to continue therapy once weekly as maintenance.
RESULTS:
Ten patients (91%) achieved CHR after a median of 2 weeks (0.5-5 weeks) of therapy. Bone marrow eosinophilia resolved in four of seven evaluable patients. The median duration of CHR was 3 months (1.5-17+ months). Seven of the 10 CHR patients relapsed, five while off-therapy. Two patients achieved second CHR upon alemtuzumab rechallenge. Three patients experienced mild infusion-related symptoms, two developed cytomegalovirus reactivation requiring therapy, and one developed orbital lymphoma that was successfully treated.
CONCLUSIONS:
Our limited experience suggests alemtuzumab to be a valuable therapy for advanced HES or CEL, refractory to standard therapies, and supports the clinical evaluation of alemtuzumab in a larger trial.