Autologous HSCT with novel agent‐based induction and consolidation followed by lenalidomide maintenance for untreated multiple myeloma

Abstract Triplet regimen comprising proteasome inhibitors, immunomodulatory drugs, and dexamethasone (DEX) is a recommended induction/consolidation therapy for multiple myeloma (MM) patients eligible for transplant. In this Japanese phase II study conducted from 2017 to 2019, newly diagnosed MM patients aged 20–65 received four induction cycles with bortezomib (Bor), lenalidomide (Len), and DEX (VRD), followed by Bor and high‐dose melphalan with autologous stem cell rescue. Subsequently, they underwent four consolidation cycles with carfilzomib, Len, and DEX (KRD), followed by Len maintenance until disease progression. A total of 141 patients were analyzed. In an intent‐to‐treat population, the complete or better response post induction was 19.9%, rising to 39.7%, 58.9%, and 62.4% after transplant, consolidation, and 1‐year maintenance, respectively. With a median follow‐up of 38 months, the 3‐year progression‐free survival (PFS) rate was 83.5% and the 3‐year overall survival rate was 92.5%. Severe adverse events (≥grade 3) occurred in ~30% of patients; however, there was no treatment‐related mortality. These findings clearly showed the tolerability and effectiveness of this protocol. Nevertheless, patients with high‐risk cytogenetics showed a trend toward lower 3‐year PFS than those without (77.8% vs. 89.4%, p = 0.051), and ultra‐high‐risk cytogenetics (≥2 high‐risk cytogenetics) had an even worse prognosis, with 61.2% 3‐year PFS. To overcome this situation, a more potent treatment strategy incorporating novel agents such as the CD38‐antibody should be assessed in future studies.