High-dose chemotherapy followed by autologous stem cell transplantation changes prognosis of IgD multiple myeloma.

Immunoglobulin D (IgD) multiple myeloma (MM) is a rare plasma cell disorder constituting less than 2% of all MM cases. Survival of patients with IgD MM is generally shorter than that of patients with other types of monoclonal (M-) protein. We have retrospectively analyzed patients with IgD MM participating in clinical trials of the Czech Myeloma Group. Twenty-six IgD MM patients treated between 1996 and 2006 were identified, 14 (54%) men and 12 (46%) women. The median age was 61 years (range: 37-79 years). Ten of 26 patients (39%) were treated with first-line high-dose chemotherapy (HDCT) using melphalan 200 mg/m(2) followed by autologous stem cell transplantation (ASCT). Thirteen of 26 patients (50%) received conventional chemotherapy (CHT), mostly melphalan and prednisone or a vincristine/doxorubicin/dexamethasone (VAD) regimen. Treatment responses were evaluable for 23 of 26 (89%) patients. All HDCT patients had treatment responses, including seven patients (70%) with complete responses and three patients (30%) with partial responses. The median progression-free survival was 18 months for HDCT patients and 20 months for CHT patients. The median overall survival (OS) for all patients was 34 months. The median OS for the HDCT group has not yet been reached (70% of the patients are still alive). In contrast, the median OS for CHT patients was only 16 months. The difference in OS between the two groups was statistically significant (P=0.005). In conclusion, the overall response rate for patients with IgD MM aged 65 years or less treated with HDCT and ASCT is similar to that seen in other MM types.