D(T)PACE as salvage therapy for aggressive or refractory multiple myeloma

Dexamethasone ± thalidomide with infusion of cisplatin, doxorubicin, cyclophosphamide, and etoposide [D(T)PACE] is generally reserved as salvage therapy for aggressive multiple myeloma (MM) or plasma cell leukaemia (PCL) resistant to conventional therapies. The efficacy and durability of this potentially toxic regimen in this setting is unclear. We identified 75 patients who received D(T)PACE for relapsed/refractory MM at two tertiary care centres: Princess Margaret Hospital, Toronto and Mayo Clinic Arizona. At time of D(T)PACE, 16 patients had PCL and three patients had leptomeningeal disease. Patients were heavily pretreated (median three prior regimens, range 1-12; prior autologous stem cell transplant [ASCT] 33%). Overall response rate was 49% (very-good partial response 16%, partial response 33%) with stable disease in an additional 36%. Median progression-free survival (PFS) was 5·5 months (95% confidence interval [CI]:4·3-9·8); overall survival (OS) 14·0 months (95% CI:8·7-19·3). Thirty-five patients proceeded to ASCT or clinical trial, with median PFS for this subset of 13·4 months (95% CI:7·7-20·1) and OS 20·5 months (95% CI:14·8-63·8). D(T)PACE is an effective salvage therapy for heavily pretreated MM patients. Although the overall response rate of 49% in this poor prognosis cohort is reasonable, the PFS is short, suggesting the best role for D(T)PACE is in bridging to definitive therapy, such as transplantation.