DP120 | A NATIONWIDE ITALIAN SURVEY ON TANDEM AUTOLOGOUS STEM-CELL TRANSPLANTATION FOR NEWLY DIAGNOSED MULTIPLE MYELOMA TREATED WITH DARATUMUMAB-BORTEZOMIB-THALIDOMIDE-DEXAMETHASONE INDUCTION

Quadruplet induction with D-VTd followed by single ASCT is the current standard treatment for NDMM in European Countries. However, in the latest EHA guidelines tandem ASCT is still recommended as an option for high-risk (HR) patients (pts), based on previous studies suggesting a survival benefit in this setting. On behalf of the GIMEMA Multiple Myeloma Working Party, we conducted a retrospective, multicenter, nationwide survey across 65 Italian centers on the use of tandem ASCT in NDMM pts from January 1st, 2022 to June 30th, 2024 (Table 1). The analysis of patients who actually received treatment are herein reported. During the study period, 2759 NDMM pts received D-VTd induction. Of these, 1106 (40.1%) pts had <60 years at diagnosis, 747 (27.1%) carried at least one HR FISH abnormality, including del17(p13), t(4;14), t(14;16), and gain/amp(1q21), and 686 (24.9%) pts had ISS 3 or R-ISS 3 disease stage. After D-VTd induction, 971 (35.2%) pts obtained ≥ CR. At data cut-off (January 9th, 2025), 1779 pts had received a single ASCT: of these, 647 (68.1%) in 2022, 744 (64.5%) in 2023, and 388 (59.1%) pts in the first six months of 2024. Over the same period, tandem ASCT was preplanned in 980 pts (35.6%) and was actually received in 741 of them: 257 (27.1%) pts in 2022, 346 (30%) in 2023, and 138 (21%) pts in the first six months of 2024. Across participating centers, the choice of tandem ASCT was based on multiple criteria, the most common being the presence at baseline of HR FISH abnormalities (86%), extramedullary disease or circulating plasma cells (66%), and advanced disease stage (37%). A suboptimal response (<VGPR) after first ASCT was a choice criterion of tandem ASCT in 34% of pts. Overall, 239 pts failed to receive a pre-planned tandem ASCT, 84 of them (35%) because of inadequate stem-cell collection and the remaining 155 pts for other reason, including treatment-related toxicities, patients’ refusal, and disease progression. At data-cut off, 1074 pts had completed D-VTd consolidation, and 2106 pts received post-ASCT maintenance therapy with lenalidomide. In the era of antiCD38-based quadruplet induction, tandem ASCT was considered an appropriate treatment option in approximately one third of NDMM Italian pts, above all with HR features, and its use was stable during the years. Poor stem-cell collection after D-VTd was the main limitation to this procedure. Lenalidomide maintenance therapy was offered to the majority of pts.