Response Improvement Rather than Response Status after First Autologous Stem Cell Transplantation Is a Significant Prognostic Factor for Survival Benefit from Tandem Compared with Single Transplantation in Multiple Myeloma Patients.

High-dose chemotherapy and autologous stem cell transplantation (ASCT) have provided effective treatment for patients with newly diagnosed multiple myeloma for more than 3 decades; however, which patients will benefit from tandem ASCT compared with single ASCT remains unclear. Here we retrospectively analyzed 978 trial and nontrial patients who underwent single or tandem ASCT in Heidelberg or other German-Speaking Myeloma Multicenter Group centers. Our results show that response improvement after first ASCT is a significant prognostic factor for progression-free survival benefit from tandem versus single ASCT (multivariable analysis, P = .002; hazard ratio, .64; 95% confidence interval, .48 to .85; P for interaction = .02). The depth of response after first ASCT and the cytogenetic profile did not have a significant prognostic effect on survival benefit from tandem ASCT. Our results suggest that it is not the response depth, but rather the response improvement after first ASCT is of prognostic significance regarding the benefit of tandem ASCT versus single ASCT.