Thalidomide-based Regimens for Elderly and/or Transplant Ineligible Patients with Multiple Myeloma: A Meta-analysis

BACKGROUND Thalidomide is an immunomodulatory and anti-angiogenic drug that has shown promise in patients with myeloma. Trials comparing efficacy of standard melphalan and prednisone (MP) therapy with MP plus thalidomide (MPT) in transplant-ineligible or elderly patients with multiple myeloma (MM) have provided conflicting evidence. This meta-analysis aimed to determine the efficacy and toxicity of thalidomide in previously untreated elderly patients with myeloma. METHODS Medline, the Cochrane Controlled Trials register, conference proceedings of the American Society of Hematology (1995-2014), the American Society of Clinical Oncology (1995-2014), and CBM, VIP, and CNKI databases were searched for randomized control trials with the use of the medical subject headings "MM " and "thalidomide ". Trials were assessed by two reviewers for eligibility. Meta-analysis was conducted using a fixed effects model. Sensitivity analysis was performed to test the robustness of the findings. RESULTS Overall, seven trials were identified, covering a total of 1821 subjects. The summary hazard ratio (thalidomide vs. control) was 0.82 (95% confidence interval [CI]: 0.72-0.94) for overall survival (OS), and 0.65 (95% CI: 0.58-0.73) for progression-free survival, in favor of thalidomide treated group. The risk ratio of complete response with induction thalidomide was 3.48 (95% CI: 2.24-5.41). A higher rate of III/IV adverse events were observed in MPT arm compared with the MP arm. However, analysis of sub-groups administering anticoagulation as venous thromboembolism prophylaxis suggested no difference in relative risk of thrombotic events between two arms (RR = 1.47, 95% CI: 0.43-5.07, P = 0.54). Further analysis of trials on the treatment effects of MPT versus MP on adverse events-related mortality showed no statistical difference between two arms (RR = 1.24, 95% CI: [0.95-1.63], P = 0.120). CONCLUSION Thalidomide appears to improve the OS of elderly and/or transplant-ineligible patients with MM when it is added to standard MP therapy.