Results of high-dose therapy for 1000 patients with multiple myeloma: durable complete remissions and superior survival in the absence of chromosome 13 abnormalities

High-dose therapy (HDT) has increased complete remission (CR) rates and survival in multiple myeloma (MM). We now report on continuous CR (CCR) and associated prognostic factors in 1000 consecutive patients receiving melphalan-based tandem HDT. Five-year CCR was 52% among 112 CR patients without chromosome 13 (▵13) abnormalities and with beta-2-microglobulin ≤ 2.5 mg/L, C-reactive protein ≤ 4 mg/L, and pre-HDT standard chemotherapy ≤ 12 months. Of all 390 CR patients without ▵13 abnormalities, 35% enjoyed 5-year CCR but none of 54 with ▵13 abnormalities. ▵13 abnormalities, present in overall 16%, reduced 5-year event-free survival from 20% to 0% and overall survival from 44% to 16% (both P < .0001). CR and a second HDT cycle applied within 6 months both extended event-free and overall survival significantly, justifying further pursuit of HDT, especially toward curing non-▵13 MM.