Thalidomide therapy for myelofibrosis with myeloid metaplasia

Abstract

BACKGROUND Thalidomide is a putative antiangiogenesis agent with activity in several hematologic malignancies. METHODS Forty‐four patients who had myelofibrosis with myeloid metaplasia received treatment with thalidomide in a Phase II clinical trial at a dose of 200 mg daily with escalation by 200 mg weekly until the best tolerated dose (maximum, 800 mg) was reached. RESULTS Seventeen of 41 evaluable patients (41%) who received treatment for at least 15 days had a response. A complete response (without reversal of bone marrow fibrosis) was achieved in 4 patients (10%), a partial response was achieved in 4 patients (10%), and hematologic improvements in anemia, thrombopenia, and/or splenomegaly were observed in 9 patients (21%). Improvements in anemia occurred in 7 of 35 patients (20%) with hemoglobin levels 9/L. Five of 24 patients (21%) became transfusion‐independent. Major or minor regression of splenomegaly was noted in 9 of 29 evaluable patients (31%), and complete regression was noted in 5 patients. Responders had a lower baseline median vascular endothelial growth factor levels (77.9 pg/mL vs. 97.7 pg/mL; P <.01) and higher median basis fibroblast growth factor levels (60.8 pg/mL vs. 37.4 pg/mL; P <.01) compared with nonresponders. Nine patients (22%) had deterioration that was attributed to thalidomide (resolved after withdrawal) with either progressive cytopenias or excessive proliferation. Two patients developed Grade 3 neutropenia with recovery and resumed therapy with dose reductions, and both later achieved a complete response. Dose‐related toxicities included fatigue (50%), constipation (48%), rash or pruritis (37%), sedation (35%), peripheral edema (29%), tremors (23%), peripheral neuropathy (22%), and orthostasis (16%). CONCLUSIONS Thalidomide warrants further evaluation in patients with MMM, particularly in combination regimens, along with the investigation of newer analogs. Cancer 2006. © 2006 American Cancer Society.