Thalidomide in multiple myeloma: lack of response of soft-tissue plasmacytomas

Thalidomide is active in patients with refractory myeloma. Seventeen patien ts (nine men/eight women, median age 73 years) with multiple myeloma (MM) w ere treated with thalidomide. Fifteen patients had refractory disease and t wo untested relapse. The median dose of thalidomide was 500 mg (range, 200- 800 mg). Nine of the 17 patients (53%) responded. The response rate was sig nificantly higher in patients with no extramedullary disease than in those with soft tissue masses (75% CI: 43-95% versus 0%: P = 001)). Of note, no d ecrease in the size of soft tissue plasmacytomas was observed in all the fi ve patients who had extramedullary involvement. This data suggests that the mechanism of action and effectiveness of thalidomide might depend on the s ite of the tumour cells.