Extended KRd + transplant for patients with NDMM provided high-quality responses with prolonged disease control and manageable tolerability
Responses were rapid, but achieving best response required extended KRd treatment for most patients
In this phase 2 multicenter study (NCT01816971), we evaluated incorporation of autologous stem cell transplant (ASCT) into a carfilzomib-lenalidomide-dexamethasone (KRd) regimen for patients with newly diagnosed multiple myeloma (NDMM). Transplant-eligible patients with NDMM received 4 cycles of KRd induction, ASCT, 4 cycles of KRd consolidation, and 10 cycles of KRd maintenance. The primary endpoint was rate of stringent complete response (sCR) after 8 cycles of KRd with a predefined threshold of ≥50% to support further study. Seventy-six patients were enrolled. Median age was 59 years (range 40-76), and 35.5% had high-risk cytogenetics. The primary endpoint was met, with an sCR rate of 60% after 8 cycles. Depth of response improved over time. On intent-to-treat (ITT), the sCR rate reached 76%. The MRD-negative rate using modified ITT was 70% by next generation sequencing (<10-5 sensitivity). After median follow-up of 56 months, 5-year progression-free survival (PFS) and overall survival (OS) rates were 72% and 84% for ITT, 85% and 91% for MRD-negative patients, and 57% and 72% for patients with high-risk cytogenetics; for high-risk patients who were MRD negative, 5-year rates were 77% and 81%. Grade 3/4 adverse events included neutropenia (34%), lymphopenia (32%), infection (22%), and cardiac events (3%). There was no grade 3/4 peripheral neuropathy. Patients with NDMM treated with KRd with ASCT achieved high rates of sCR and MRD-negative disease at the end of KRd consolidation. Extended KRd maintenance post-consolidation contributed to deepening of responses and likely to prolonged PFS and OS. Safety and tolerability were manageable.