Closing the Efficacy and Effectiveness Gap: Outcomes in Relapsed/Refractory Multiple Myeloma (RRMM) Patients (Pts) Treated with Ixazomib-Lenalidomide-Dexamethasone (IRd) in Routine Clinical Practice Remain Comparable to the Outcomes Reported in the Phase 3 Tourmaline-MM1 Study

Background Ixazomib, the first oral proteasome inhibitor, has been approved for >3 years in >70 countries, for the treatment of RRMM pts who have received ≥1 prior therapy, on the basis of the TOURMALINE-MM1 study, which reported an overall response rate (ORR) of 78% and median progression free survival (PFS) of 20.6 mos. Although outcomes and tolerability in routine clinical practice often differ from data reported in clinical trials, growing evidence suggest that outcomes in patients treated with ixazomib-based regimens are comparable to those in the Phase 3 TOURMALINE-MM1 trial. We report on an expanded pooled analysis with longer follow-up of IRd therapy from the INSIGHT MM study (NCT02761187) and the Czech Registry of Monoclonal Gammopathies (RMG) to evaluate the effectiveness of IRd in RRMM pts in routine clinical practice. Methods INSIGHT MM is a large, prospective, observational study which has enrolled over 4,200 adult pts with MM from Europe (plus Israel, EUR), the US, Asia, and Latin America, with a planned follow-up of ≥5 years. The RMG comprises clinical data for >6,000 MM pts enrolled at 19 Czech and 4 Slovak centers. Eligible pts had 1-3 (INSIGHT) or ≥1 prior therapy (RMG) including an IR-based regimen. Individual pt level data on demographics, disease characteristics, treatment history, effectiveness, and safety from INSIGHT and RMG were integrated and analyzed. Best response or time to first response and PFS were determined as per investigator assessment, using IMWG criteria. PFS, duration of treatment (DOT), and overall survival (OS) were estimated using Kaplan Meier (KM) methodology, applying an exclusion criterion to account for immortal time bias (INSIGHT only). Results At data cutoff of 22 Nov 2018, 217 pts (83 in INSIGHT and 134 in RMG) from 11 countries had been included: 191 (88%) from EUR, 17 (8%) from the US, and 9 (4%) from Taiwan; 89% of pts were treated in an academic facility. At diagnosis, 32% of pts had ISS Stage III disease, 78% had bone lesions, 46% had anemia, and 12% had elevated creatinine. At study start, median age was 67 years with 12% >75 years; 58%/14% of pts had ECOG performance status 1/2. The distribution of immunoglobulin (Ig) heavy and light chain MM was as expected; 69% of pts had IgG MM. Overall, 21% of pts had extramedullary disease. Prior therapies included: bortezomib (90%), stem cell transplant (60%), thalidomide (47%), lenalidomide (26%), carfilzomib (8%), daratumumab (6%), and pomalidomide (2%). Media