Improved survival of patients with primary plasma cell leukemia with VRd or daratumumab‐based quadruplets: A multicenter study by the Greek myeloma study group

Abstract

AbstractWe evaluated the efficacy and prognostic impact of bortezomib‐lenalidomide triplet (VRd) or daratumumab‐based quadruplets (DBQ) versus previous anti‐myeloma therapies, that is, bortezomib standard combinations (BSC) or conventional chemotherapy (CT), in a large cohort of patients with primary plasma cell leukemia (pPCL), including those fulfilling the revised diagnostic criteria, that is, circulating plasma cells (cPCS): ≥5%; 110 pPCL patients (M/F: 51/59; median age 65 years, range: 44–86) out of 3324 myeloma patients (3%), registered in our database between 2001 and 2021, were studied; 37% had cPCS 5%–19%; 89% received novel combinations including DBQ (21%), VRd (16%) and BSC (52%); 35% underwent autologous stem cell transplantation. 83% achieved objective responses. Treatment with VRd/DBQ strongly correlated with a higher complete response rate (41% vs. 17%; p = .008). After a median follow‐up of 51 months (95% CI: 45–56), 67 patients died. Early mortality was 3.5%. Progression‐free survival was 16 months (95% CI: 12–19.8), significantly longer in patients treated with VRd/DBQ versus BSC/CT (25 months, 95% CI: 13.5–36.5 vs. 13 months 95% CI: 9–16.8; p = .03). Median overall survival (OS) was 29 months (95% CI: 19.6–38.3), significantly longer in patients treated with VRd/DBQ versus BSC/CT (not reached vs. 20 months, 95% CI: 14–26; 3‐year OS: 70% vs. 32%, respectively; p < .001; HzR: 3.88). In the multivariate analysis VRd/DBQ therapy, del17p(+) and PLT <100.000/μL, independently predicted OS (p < .05). Our study has demonstrated that in the real‐world setting, treatment with VRd/DBQ induces deep and durable responses and is a strong prognostic factor for OS representing currently the best therapeutic option for pPCL.