MM-435: Propensity Score Matching Analysis to Evaluate Bortezomib/Cyclophosphamide /Dexamethasone and Bortezomib/Thalidomide/Dexamethasone from Real-World Data in Patients with Newly Diagnosed Multiple Myeloma, on Behalf of the Colombian Multiple Myeloma Registry

Context The most frequently used induction treatments for newly diagnosed multiple myeloma in Colombia are VTD and CyBorD for transplant-eligible patients. Objective At present, there are no clinical studies in our region that compare the effectiveness of these two regimens. Design To reduce the bias between the groups, we performed a 1:1 propensity score matching (PSM) technique for analysis. Setting The Registro Epidemiologico de Neoplasias Hematologicas en Colombia (RENEHOC) collected data electronically on Colombian patients with multiple myeloma between 2010 and 2018. Patients or Other Participants After pairing using PSM by nearest neighbor, a total of 448 patients, 224 in each group, were identified. Patients in the two groups were matched for age, sex, myeloma type, international staging system stage at diagnosis, kidney injury, dialysis, extramedullary involvement, and transplantation. Interventions None. Main Outcomes Measures Overall response rate and overall survival. Results In the unpaired model, statistically significant differences were shown in age, which was corrected after running the PSM. In all the variables used for the model, no differences were shown between the two groups. The VTD regimen tends to be favored 73.47% vs 63.68% p = 0.061 in the unpaired model; however, when the analysis is made after the PSM, the differences dissipate and become non-significant 68.75% vs 73.66% p = 0.565. There were no statistically significant differences for complete response or very good partial response. We did an overall survival analysis for each regimen whether or not they had undergone transplantation. The median overall survival in the transplanted VTD group was 34 months IQR (20–54) and in VTD not taken to transplantation, it was 8 months IQR (5–17) p Conclusions VTD or CyBorD were equally effective in terms of response and survivability in real world practice. Overall survival was adversely affected when patients did not undergo autologous bone marrow transplantation, regardless of the regimen used in induction.