Time to first disease progression, but not beta2-microglobulin, predicts outcome in myeloma patients who receive thalidomide as salvage therapy

BACKGROUND: Baseline parameters that may be predictive of outcome after thalidomide treatment have been investigated to identify which myeloma patient subgroups will most benefit from this drug. METHODS: Thalidomide has been used as a salvage regimen at the study institution since 1999. A total of 102 myeloma patients who were diagnosed between January 1999 and February 2005 were evaluable for intention-to-treat analysis; 78 patients received thalidomide (at a dose of 100 mg/day continuously) and dexamethasone (at a dose of 40 mg/day on Days 1-4 each month) (TD) as salvage treatment whereas 24 patients died or were lost to follow-up before the initiation of TD. Several parameters such as serum beta2-microglobulin, serum C-reactive protein, immunoglobulin A isotype, hemoglobin, stage of disease, bone marrow plasmacytosis, age, serum creatinine, gender, stem cell transplantation at the time of diagnosis, and time to first disease progression were analyzed in association with overall survival (OS). RESULTS: The OS from the time of diagnosis was 43.8 months. Using univariate analysis, factors found to be associated with a shorter OS were a creatinine level > or =2 mg/dL (P = .05), stage III (P = .04), and time to first disease progression < or =12 months (P < .0001). The only factor that remained significantly associated with a shorter OS in multivariate models was time to first disease progression < or =12 months (P = .0006). Elevated serum beta2-microglobulin was not found to be predictive of poor OS. CONCLUSIONS: Time to first disease progression >12 months was found to be the best indicator of OS. Elevated serum beta2-microglobulin, generally considered to be a poor prognostic factor, was not found to be predictive of outcome.