Response rate, durability of response, and survival after thalidomide therapy for relapsed multiple myeloma.

To assess response rate, duration of response, progression-free survival, and toxicity of thalidomide in patients with relapsed multiple myeloma. Thirty-two patients with relapsed multiple myeloma were entered into the study between April 29, 1999, and June 20, 2000. They were given oral thalidomide at a dosage of 200 mg/d for 2 weeks, which was then increased as tolerated to a maximum of 800 mg/d. The primary end point of the study was response rate. The median age of the patients was 67 years (range, 36-78 years). Prior chemotherapy had failed in all patients, and stem cell transplantation had failed in 5 patients (16%). There were 10 confirmed responses, yielding a response rate of 31%. In addition, there was 1 unconfirmed partial response and 7 minimal responses with no complete responses. The median duration of response was 11.9 months (range, 3.7-203 months). Overall, 20 patients have died, and 26 patients have experienced disease progression. The median follow-up of surviving patients was 28.5 months (range, 193-34.0 months), with a median progression-free survival of 8.6 months (95% confidence interval [CI], 4.7-16 months). The median progression-free survival among the responding patients was 15.7 months (95% CI, 8.6-25.6 months). The median overall survival for the entire group was 22 months (95% CI, 10.6-35.9 months). The most common treatment-related nonhematologic toxic effects (grade >3) were neuropathy (16%), sedation (13%), febrile neutropenia (6%), and constipation (6%). Thalidomide is useful in the treatment of patients with relapsed multiple myeloma and produced durable response in approximately one third of patients, with median response duration of nearly 1 year.