Thalidomide Effective in Newly Diagnosed Multiple Myeloma

ROCHESTER, Minnesota—Previous studies have shown the benefits of thalidomide (Thalomid) in patients with relapsed multiple myeloma. Now, researchers from the Mayo Clinic report that the oral combination of thalidomide and dexamethasone is feasible and active as initial therapy of the disease.

The phase II study involved 50 patients with previously untreated myeloma. Thalidomide was given orally at a dose of 200 mg/d. Dexamethasone was given orally at a dose of 40 mg/d on days 1 to 4, 9 to 12, and 17 to 20 (odd cycles) and 40 mg/d on days 1 to 4 (even cycles), repeated monthly.

The confirmed response rate (greater than 50% reduction in M-protein in both blood and urine) was 64% (32 patients), said lead author S. Vincent Rajkumar, MD, of the Division of Hematology. An additional 14 patients (28%) achieved a reduction in M-protein of 25% to 50%. Reduction in M-protein levels was accompanied by hematologic recovery from anemia, leukopenia, and thrombocytopenia. A total of 31 patients went on to stem cell collection after four cycles, and 26 underwent stem cell transplantation (J Clin Oncol 20:4319-4323, 2002).

The rate of major grade 3-4 toxicities was 32% (16 patients); the most frequent such events were deep vein thrombosis (six patients), constipation (four patients), rash (three patients), and dyspnea (two patients). There were three deaths during active therapy, due to pancreatitis, pulmonary embolism, and infection.

The authors concluded that the combination "merits further study as an oral alternative to infusional chemotherapy with vincristine, doxorubicin, and dexamethasone and other intravenous regimens currently used as pretransplan-tation induction therapy for myeloma." Dr. Rajkumar is lead investigator of an ongoing ECOG phase III study to further evaluate the efficacy of thalidomide plus dexamethasone vs dexamethasone alone in patients with newly diagnosed multiple myeloma.