Efficacy of low-dose thalidomide and dexamethasone as first salvage regimen in multiple myeloma

The efficacy of low-dose thalidomide (THAL) plus dexamethasone (DEX) has been evaluated in myeloma. The clinical outcome of patients treated with THAL-DEX was compared with that of a control group treated with conventional chemotherapy (CC).

A total of 120 relapsed/refractory patients to one (52%), or two or more(48%) lines of chemotherapy were treated with THAL 100mg/day (continuous) and DEX 40 mg (days 1-4 of each month). Their clinical outcome was compared to a control group of 120 patients frequency matched for serum beta2-microglobulin levels and Durie and Salmon clinical stage. Clinical characteristics were homogeneous in the two groups.

In patients treated after one line of chemotherapy, THAL-DEX significantly improved outcome. Median progression-free survival (PFS) was superior in THAL-DEX group versus CC group (17 months versus 11 months, P = 0.0024). The median survival for THAL-DEX patients has not to been reached, but the probabilities of survival at 3 years were 60% after THAL-DEX and 26% after CC (P = 0.0016). The clinical outcome of patients receiving THAL-DEX or CC after two or more lines of chemotherapy, was similar. In the THAL-DEX group, the medianPFS was 11 months compared to 9 months in the CC group (P = NS). No differences in overall survival (OS) were observed (median OS 19 months for both THAL-DEX and CC).

As first salvage regimen, THAL-DEX was superior to CC, as second or third salvage regimen, it was equivalent to CC. THAL-DEX is not myelotoxic. It postpones the delivery of effective salvage chemotherapy. This might explain the survival benefit.