Consolidation therapy of multiple myeloma with thalidomide-dexamethasone after intensive chemotherapy

Background: After myeloablative therapy for multiple myeloma, progression-free survival is shorter for disease in partial remission rather than complete remission. In an attempt to induce more frequent complete remission, we assessed thalidomide-dexamethasone in patients with stable partial remission after intensive therapy. Patients and methods: Twenty-one patients with multiple myeloma were identified with disease in stable partial remission after prior intensive therapy. Thalidomide-dexamethasone was given within 15 months after intensive therapy provided myeloma protein production had been reduced by >75% to a constant level for at least 4 months. Thalidomide was begun at a dose of 100 mg each evening, with increments of 50 mg every 7 days to a maximum of 300 mg. Dexamethasone was given concurrently in a dose of 20 mg/m² each morning for 4 days on days 1-4, 9-12 and 17-20, with resumption on day 35. The combination was continued for at least 3 months and patients with marked reduction of myeloma were maintained on thalidomide alone until disease progression. Results: Marked further reduction of myeloma by at least 90% occurred in 12 patients (57%), including four (19%) with disease converted to complete remission. Disease has progressed in six of 21 patients, whose median total remission was 22 months. Common side effects of constipation, fatigue, paresthesias and dry skin were mild, dose-related and reversible. Conclusions: The combination of thalidomide-dexamethasone reduced tumor mass markedly in 57% of patients with stable, residual disease after myeloablative therapy. Such an effect may produce longer disease-free survival and/or preserve tumor sensitivity to later retreatment with previously effective drugs.