Impact of maintenance therapy post autologous stem cell transplantation for multiple myeloma in early and delayed transplant.

Based on phase 3 trials, maintenance therapy after autologous stem cell transplantation (ASCT) has become the standard of care in multiple myeloma (MM). We examined the trends in maintenance therapy in a large group of patients (2530) transplanted at a single institution over two decades. Majority (n = 1958; 77%) had an ASCT within 12 months of diagnosis (early ASCT). Maintenance was employed in 39% of the patients; 42% among early ASCT and 30.5% among delayed ASCT. Most common maintenance approach was an IMiD (61%), followed by a PI (31%), or a PI + IMiD (4%). Patients with high-risk FISH received PI-based maintenance more frequently. The PFS was superior with maintenance (36 vs. 22 months, p < 0.001); 37 vs. 25 months for early ASCT (p < 0.001) and 29 vs. 17 months for delayed ASCT (p = 0.0008). OS from ASCT was higher with maintenance for the whole cohort at 93 vs. 73 months (p < 0.001). OS from diagnosis was also better for the whole cohort with maintenance therapy, 112 vs. 93 months (p < 0.001). The improvement in PFS and OS was seen in high-risk and standard risk disease. The experience with maintenance therapy post ASCT for myeloma in a non-clinical trial setting confirms the findings from the phase 3 trials.