Myeloma XIV: A Phase III Trial to Compare Standard and Frailty-adjusted Induction Therapy With Ixazomib, Lenalidomide and Dexamethasone (IRD) and Maintenance Lenalidomide (R) to Lenalidomide Plus Ixazomib (R+I)

Trial Title: FiTNEss (UK-MRA Myeloma XIV) - Frailty-adjusted therapy in Transplant Non-Eligible patients with newly diagnosed Multiple Myeloma Overview: A phase III, multi-centre, randomised controlled trial to compare standard (reactive) and frailty-adjusted (adaptive) induction therapy delivery with the novel triplet ixazomib, lenalidomide and dexamethasone (IRD), and to compare maintenance lenalidomide (R) to lenalidomide plus ixazomib (R+I) in patients with newly diagnosed multiple myeloma not suitable for a stem cell transplant. All participants receive induction treatment with ixazomib, lenalidomide and dexamethasone and are randomised on a 1:1 basis at trial entry to the use of frailty score-adjusted up-front dose reductions vs. standard up-front dosing followed by toxicity dependent reactive dose-modifications during therapy. Following 12 cycles of induction treatment participants alive and progression-free undergo a second randomisation on a 1:1 basis to maintenance treatment with lenalidomide plus placebo versus lenalidomide plus ixazomib. Participants and their treating physicians will be blinded to maintenance allocation. Participant population: * Newly diagnosed as having Multiple Myeloma (MM) according to the updated IMWG diagnostic criteria 2014 (see Appendix 1 for criteria) * Not eligible for stem cell transplant * Aged at least 18 years * Able to provide written informed consent Number of participants: 740 participants will be entered into the trial at Randomisation 1 (R1), with 478 participants at Randomisation 2 (R2). Objectives: The primary objectives of this study are to determine: * Early treatment cessation (within 60 days of randomisation) for standard versus frailty-adjusted up-front dosing * Progression-free survival (PFS, from maintenance randomisation) for lenalidomide + placebo (R) versus lenalidomide + ixazomib (R+I) The secondary objectives of this study are to assess progression-free survival (PFS) for standard versus frailty-adjusted up-front dosing reductions, time to progression, time to 2nd PFS event (PFS2), overall survival (OS), survival after progression, deaths within 12 months of R1, overall response rate (ORR), attainment of ≥VGPR, attainment of MRD negativity, duration of response, time to improved response, time to next treatment, treatment compliance and total amount of therapy delivered, toxicity \& safety including the incidence of SPMs, Quality of Life (QoL), cost effectiveness of standard versus frailty-adjusted up-front dosing of IRD and cost-effectiveness of R + I versus R. Exploratory objectives are prospective validation of a novel frailty risk score (UK-MRA Myeloma Risk Profile - MRP), usefulness of Karnofsky Performance Status (PS), and association of molecular subgroups with response, PFS and OS.