Maintenance therapy in newly diagnosed multiple myeloma: current recommendations

A phase I/II dose-escalation study investigating all-oral ixazomib-melphalan-prednisone induction followed by single-agent ixazomib maintenance in transplant-ineligible newly diagnosed multiple myeloma

This phase I/II dose-escalation study investigated the all-oral ixazomib-melphalan-prednisone regimen, followed by single-agent ixazomib maintenance, in elderly, transplant-ineligible patients with newly diagnosed multiple myeloma. Primary phase I objectives were to determine the safety and recommended phase II dose of ixazomib-melphalan-prednisone. The primary phase II objective was to determine the complete plus very good partial response rate. In phase I, patients were enrolled to 4 arms investigating weekly or twice-weekly ixazomib (13 28-day cycles or nine 42-day cycles) plus melphalan-prednisone. In phase II, an expansion cohort was enrolled at the recommended phase II ixazomib dose. Of the 61 patients enrolled, 26 received the recommended phase II dose (ixazomib 4.0 mg [days 1, 8, 15] plus melphalan-prednisone 60 mg/m² [days 1-4], 28-day cycles). Of the 61 enrolled patients, 36 (13 of 26 in the recommended phase II dose cohort) received single-agent ixazomib maintenance (days 1, 8, 15; 28-day cycles). In phase I, 10/38 patients reported dose-limiting toxicities in cycle 1, including grade 3 and/or 4 neutropenia (n=6) and thrombocytopenia (n=4). Complete plus very good partial response rate was 48% (48% at recommended phase II dose), including 28% (22%) complete response or better; responses deepened during maintenance in 34% (33%) of evaluable patients. After median follow up of 43.6 months, median progression-free survival was 22.1 months. Adverse events were mainly hematologic events, gastrointestinal events, and peripheral neuropathy. This study demonstrates the feasibility, tolerability, and activity of ixazomib-melphalan-prednisone induction and single-agent ixazomib maintenance in transplant-ineligible newly diagnosed multiple myeloma patients. clinicaltrials.gov identifier 01335685.

Curing myeloma at last: defining criteria and providing the evidence

Does the dogma that multiple myeloma is incurable still hold?. The genomic chaos and resulting resistance to apoptosis of myeloma, long considered an obstacle to cure, formed the basis of Total Therapy (TT) program. The TT approach uses all myeloma-active drugs upfront to target drug-resistant subclones during initial treatment to prevent later relapse. Long-term follow-up of 1202 patients (TT1: n = 231, median follow-up: 21 years; TT2: 668, median follow-up: 12 years; TT3a: n = 303, median follow-up: 9 years) permitted investigation of whether progression-free survival (PFS) and complete response (CR) duration were consistent with curability, ie observation of plateaus in Kaplan-Meier plots for PFS and CR duration. In the subset of 627 patients with plasma cell gene expression profiling data, cure plateaus were apparent at 5 years in the 14% with high-risk myeloma compared with 10 years in the remainder with low-risk disease. A parametric model based on PFS and CR duration supported an increase in curability: 10-year PFS and CR estimates increased from 8.8%/17.9% in TT1 to 15.5%/28.2% in TT2's control arm to 25.1%/35.6% in TT2's thalidomide arm and to 32.9%/48.8% in TT3a. Toward developing novel therapies, we recommend a concerted focus on patients with high-risk myeloma whose outcome has not been advanced.