Comparison of Maintenance Therapy Regimens of Patients Treated for Multiple Myeloma

Background: Despite significant progress in treatment modalities and improved survival and response rates in patients diagnosed with multiple myeloma (MM), it remains an incurable disease with a poor outcome, especially in high-risk groups. Though not all patients are eligible, autologous stem-cell transplantation (ASCT) remains an integral part of the treatment of patients with both newly diagnosed and relapsed MM. Regardless of whether patients receive a transplant, they do receive maintenance therapy, and recent evidence has demonstrated that maintenance therapies offer an advantage in progression free and overall survival. While Revlimid is the standard of care, data regarding the specifics of maintenance therapy in high-risk patients is limited and the overall impact of various regimens on survival needs to be further investigated. In our retrospective chart review we reviewed all adult patients with advanced MM within Henry Ford Cancer Institute in the last 10 years to determine the impact of maintenance therapy on progression free survival (PFS) and overall survival (OS).

Methods: We conducted a retrospective chart review of adult patients with MM who underwent ASCT between January 1, 2012 to December 31, 2022. Those who received maintenance chemotherapy after transplant were included in the study. Patients who were lost to follow-up or who had largely incomplete records were excluded. Data points including age, ethnicity, cytogenetic analysis, risk category, maintenance regimen after transplant, last chemotherapy regimen, last follow-up, and date of death (if applicable) were recorded. Maintenance chemotherapy regimens were recorded as Revlimid versus other. Patients were split into 2 categories based on risk - high risk and standard risk. Kaplan-Meier plots were used to illustrate overall survival and time to relapse between groups for various variables. Statistical significance was set at p<0.05

Results: 158 patients were included in the study of which 44 were considered high-risk based on cytogenetics, 106 were standard-risk and 8 were missing. Most of the patients (n=137, 87.3%) received Revlimid, while 20 (12.7%) received maintenance therapy other than Revlimid, and for 1 patient, the type of maintenance therapy was unknown. Within the high-risk group, no statistical significance in OS or PFS was found between patients that received Revlimid versus those that did not. Furthermore, there was no statistical significance in OS and PFS within high risk versus standard cytogenetic risk groups.

Conclusions: We did not see a difference in outcome based on risk and believe all patients would derive equal benefit from maintenance therapy We also did not see a difference in outcome between high and standard risk patients, and for the high-risk subgroup, there was a separation in curves suggesting that maintenance therapy has benefit compared to no maintenance.