Maintenance with pamidronate following first-line MP or VAD therapy in multiple myeloma

We investigated the anti-tumor effect of pamidronate after obtaining a decrease of serum monoclonal immunoglobulin (Ig) level by conventional chemotherapy in patients with multiple myeloma (MM) in order to evaluate whether the drug is useful as maintenance therapy for MM. Eight patients with MM received 60 mg/d pamidronate every third week for 6-18 months without chemotherapeutic agents or corticosteroids after the treatment with melphalan and prednisolone, or vincristine, adriamycin and prednisolone. Serum Ig and beta2-microglobulin (b2MG) levels were maintained at the levels obtained after the termination of chemotherapy in six and four out of eight patients, respectively. Hemoglobin levels were maintained at, or increased to more than, the levels observed at the end of chemotherapy in six patients. Decreased plasma cells in the bone marrow after the chemotherapy were evident in five patients. Two patients were categorized as non-responders, because Ig and b2MG increased and anemia progressed after treatment with the drug. Despite the very small numbers, the results suggest that pamidronate may have anti-tumor activity and be useful for treatment after the conventional chemotherapy in some cases of MM.