DP098 | MAINTENANCE AFTER AHCT IMPROVES OS AND PFS REGARDLESS OF RESPONSE STATUS AT TRANSPLANT IN NEWLY DIAGNOSED MYELOMA PATIENTS: A GLOBAL, REAL-WORLD ANALYSIS FROM THE WORLDWIDE NETWORK FOR BLOOD AND MARROW TRANSPLANTATION GLOBAL STUDY

In eligible NDMM, AHCT is the standard of care. Real-world global demographic and outcome data on impact of maintenance post-AHCT are scarce. Using a global registry,we explored if maintenance could overcome a suboptimal response at time of AHCT. The study included 61988 patients NDMM receiving AHCT between 2013 and 2017. Data were based on WBMT through the EBMT, CIBMTR, APBMT, EMBMT, LABMT (Table 1). The median age at AHCT was 60.1 (53.6-65.5) and only 4.9% of patients were older than 70 years. Disease stage at diagnosis was ISS I in 36.7%,ISS II in 35.2 %and ISS III in 28.1% and HR 31.2%,considering as “high risk” patients with deletion 17p ,t(4:14)or t(14:16).In our cohort,maintenance treatment is increasing between 2013 and 2017 from 14.1%to 29.8%. Disease status before AHCT was: CR 19.9%%, VGPR 38.7%, PR 35,4%, SD/MR 4.6%, RR/PD1,4%. Among the whole population in WBMT,11% had information about maintenance:51% received Lenalidomide maintenance, 10% Thalidomide, 8% Bortezomib and 11% none. After a median follow-up of 45 months post AHCT,in univariable analyses,Lenalidomide and Thalidomide and Bortezomib maintenance are all associated with improved OS,PFS, lower RI and NRM compared to no maintenance,regardless of disease status at HCT. In the MVA better response status at AHCT was significantly associated with better OS and PFS.The OS HR in Lenalidomide maintenance for VGPR, PR, SD/MR and Rel/Prog vs CR at AHCT was 1.07,1.23, 1.79 and 2.71(p=0.0003).For PFS, these estimates were 1.12,1.43,1.78and 2.10 ( p<0.0001).The benefit of Lenalidomide maintenance decreased overtime after AHCT, HR3.89at 6 months to1.02 at 36 months. Lower ISS was associated with better OS (HR II vs I 1.34and III vs I 2.29).No maintenance was associated with worse OS and PFS compared to lenalidomide maintenance, HR1.91and 1.77. The HR comparing Thalidomide vs lenalidomide for OS was 1.36, and for PFS was1.48,p=0.04 and <0.0001. The HR Bortezomib vs Lenalidomide was for OS 1.03 and PFS 1.48,p=0.82 and <0.0001. Thalidomide or Bortezomib maintenance showed advantage in OS with an HR of 2.06and 2.29for High cytogenetic risk and ISS III, also seen with PFS(HR 1.65 and 1.79,(p <0.0001). In this study,patients who underwent upfront AHCT for MM, Lenalidomide maintenance confirmed an improve in PFS and OS. Patients with CR as well as those with suboptimal response at AHCT benefit from maintenance.Both thalidomide and bortezomib maintenance showed improved PFS and OS compared to no maintenance, but were inferior to lenalidomide.