VTd-PACE and VTd-PACE-like regimens are effective salvage therapies in difficult-to-treat relapsed/refractory multiple myeloma: a single-center experience

Although treatment options for multiple myeloma (MM) are rapidly evolving, there still remain difficult-to-treat situations, especially in relapsed and/or refractory (r/r) disease. When modern therapies are exhausted, or emergency treatment is needed for high tumor burden, classic chemotherapy combination regimens like the VTd-PACE regimen and its modifications (PACE-M) may also be beneficial as bridging to subsequent treatment options. This single-center retrospective analysis aimed to investigate the outcome of VTd-PACE and PACE-M salvage therapy in 31 heavily pretreated r/r MM patients. The primary objective was the overall response rate (ORR). Secondary objectives were median progression-free survival (mPFS), median overall survival (mOS), safety, and renal response. Median age was 59 years (range 39-75), and 71% of patients were male. R-ISS stratification showed high-risk MM in 48%. The median number of prior therapies was 3, with 23 patients being triple- and 12 penta-refractory (74% and 39%). ORR was 71%, including 23% of patients achieving a very good partial response. Median duration of follow-up was 15 months (range 0-29 months). mPFS and mOS were 3 months (95% CI 0.27-5.74) and 11 months (95% CI 3.66-18.35), respectively. In 26 patients (83.9%), at least one subsequent treatment (stem cell transplant or BCMA-directed) was administered. Renal function significantly improved after VTd-PACE or PACE-M treatment (p = 0.032). Non-hematological adverse events >= grade 3 were predominantly infections. VTd-PACE and PACE-M are effective salvage therapies in difficult-to-treat situations in heavily pre-treated r/r MM, including patients with impaired renal function. VTd-PACE and PACE-M can be successfully used as bridging therapy for subsequent treatment.