Immunoglobulin D Multiple Myeloma: Clinical Presentation, Response to Therapy and Prognostic Factors in 75 Patients; An Analysis of the Korean Multiple Myeloma Working Party (KMMWP).

The primary objective of this study was to analyze the clinical and laboratory characteristics, response to therapy, and survival in patients with IgD multiple myeloma. The secondary objectives were to evaluate the efficacy of treatment, including autologous stem cell transplantation, in these patients.

Records of 75 patients with IgD multiple myeloma from 18 institutions were reviewed using the Korean Myeloma Registry (KMR) database (www.myeloma.co.kr).

Median patient age was 57 years (range, 34∼81 years) and 67% were male. The main presenting features were bone pain (77%) and fatigue (77%). Thirty patients (40%) had ECOG PS ≥ 2, and 71 (94%) had ≥1 lytic bone lesions. Renal function impairment (sCr level ≥2 mg/dL) and hypercalcemia (sCa level ≥12 mg/dL) were present in 53% and 27% of patients, respectively. Median serum M protein level was 1.4 g/dL, and 89% of patients had lambda light chains. Forty-nine patients (65%) were stage III by the ISS and 92% were stage III by DSS. Forty-nine patients were assessable for chromosomal analysis, 46 by conventional cytogenetics and 3 by FISH analysis. Of these, 23 patients (47%) had chromosomal abnormalities associated with poor prognosis. Thirty-nine patients (52%) were treated with VAD chemotherapy; the 36 patients assessable for response had an objective response rate of 59%. Eighteen patients (24%) received first-line combination chemotherapy including new drugs (bortezomib or thalidomide) and their objective response rate was 88%. At a median follow up of 28.6 months for the surviving patients, the median OS was 18.5 months and median PFS was 10.4 months. Multivariate analysis showed that age ' 65 (vs > 65), absence of extramedullary plasmacytoma, absence of del(13) or hypoploidy and serum beta-2 microglobulin level <8.0 mg/dL (vs ≥ 8.0mg/dL) were significant prognostic factors for OS. Thirty-four patients (45%) underwent SCT, 32 as part of their initial therapy. For patients who received SCT after complete or partial response to initial therapy, the median OS was 30 months.

IgD multiple myeloma is an aggressive disease that is usually detected at an advanced stage. Despite initial response, survival after relapse is dismal. Intensive treatment strategies to induce high quality responses before SCT may improve outcomes in younger patients.

Suh:Janssen Korea: Research Funding.