Immunoglobulin D multiple myeloma: Response to therapy, survival, and prognostic factors in 75 patients

Background: To analyze the clinical features, outcomes including efficacy of treatment, and prognostic factors of patients with immunoglobulin D multiple myeloma (IgD MM). Design and methods: Seventy-five patients diagnosed with IgD MM were selected from the Korean Myeloma Registry database (www.myeloma.or.kr). Results: Median age was 57 years and the main presenting features were bone pain (77%). Renal function impairment and hypercalcemia were present in 40 (53%) and 20 (27%) patients. Sixty-seven patients (89%) had lambda light chains. Forty-eight patients (64%) were of stage III by International Staging System. Twenty-six patients (53%) had chromosomal abnormalities mostly by conventional cytogenetics. Thirty-nine patients (54%) were treated with vincristine, adriamycin, and dexamethasone chemotherapy; the overall response rate (ORR) of 56%. Sixteen patients (22%) received first-line chemotherapy including new drugs (bortezomib or thalidomide), with an ORR of 81%. At a median follow-up time of 28.6 months, median overall survival (OS) was 18.5 months. Age, extramedullary plasmacytoma, del(13) or hypoploidy, serum β₂ microglobulin level, and platelet count were significant prognostic factors for OS. Conclusions: IgD MM is an aggressive disease that is usually detected at an advanced stage. Despite a positive initial response, survival after relapse was dismal. Intensive treatment strategies before and following stem cell transplantation may improve outcomes in younger patients.