Addition of thalidomide to melphalan and prednisone treatment prolongs survival in multiple myeloma - a retrospective population based study of 1162 patients

The combination of melphalan and prednisone (MP) has been the standard treatment of multiple myeloma (MM). Since the introduction of novel agents, the clinical outcome in MM has improved. Six randomized prospective studies with thalidomide combined with melphalan and prednisone (MPT) compared to MP have been performed, most of them showing that MPT gives a better response rate and median overall survival (OS). Amongst 1843 MM patients admitted to 15 Swedish centres, we selected all patients treated with MP and MPT in first, second, third or fourth line of therapy, in total 888 patients treated with MP and 274 with MPT. Patients were evaluated for response rate, OS and Time to Next Treatment. Multivariate Cox model analysis was made to adjust for different criteria at time for MM-diagnosis. The median OS from beginning of first line of treatment was 2.2/4.2yrs after MP/MPT respectively, and in second, third and fourth line of treatment 1.8/2.9, 1.4/1.6 and 1.1/1.9yrs (P<0.0001, 0.003, 0.74 and 0.235). The relative risk for death in the MPT group vs. the MP group was 0.61 (95% CI: 0.45-0.84) in first and 0.55 (0.38-0.83), P<0.01) in second line. Treatment with MPT gave a significantly better OS rate after both first and second line of therapy when compared with treatment with MP only.