Sborov, Doug

Introduction: Extra copies of chromosome 1q21 (+1q: gain=3 copies, amp=4 or more copies) have been associated with worse outcomes for patients with multiple myeloma (MM). We performed a systematic review to evaluate current reporting of +1q, efficacy of existing regimens for +1q, and prognostic implications of +1q in MM randomized controlled trials (RCTs). Methods: We searched three databases for MM RCTs. Our inclusion criteria were all published MM RCTs from 2012-2022. Each MM RCT was analyzed for reported data on +1q. The following features specific to +1q were collected: +1q reported or not as a high-risk cytogenetic alteration, definition of gain1q with respect to percentage of cells with abnormality detected, documentation of distinction between Gain1q and Amp1q in analysis, prevalence of +1q in enrolled population, outcomes of patients [Overall Survival (OS) and Progression Free Survival (PFS)] in patients with +1q in the experimental versus control arm and in patients with and without +1q. Results: A total of 124 trials were included. Among these trials, 28 (23%) studies reported data on +1q, including 26 studies that reported data in the primary manuscript and two studies that reported in separate publication. These trials reported a total of 2692 patients with +1q which represented 25% of all the patients enrolled. Out of 28 trials, three trials (11%) specified the criteria for categorizing patients as +1q (example in IKEMA and IFM-99: the presence of at least three copies in at least 30% of analyzed plasma cells was required). Only four trials (14%) reported survival data on gain and amp separately and the remaining 24 (86%) studies reported for gain or did not specify gain vs amp. Amongst the trials that reported +1q, 22 (79%) considered this to be a high-risk cytogenetic abnormality. Amongst trials that met primary endpoint showing improvement in PFS and clearly reported on +1q, the following drugs also improved PFS for those with +1q (when comparing hazard ratio (HR) for intervention versus control arm in the +1q subgroup): lenalidomide (len) maintenance in Myeloma XI, selinexor in BOSTON, and isatuximab in IKEMA and ICARIA. Several trials met their endpoint and showed improvement in PFS in the +1q cohort in same direction as overall study results but had confidence intervals for +1q subgroup that crossed 1. These included addition of carfilzomib in Myeloma XI, addition of carfilzomib vs bortezomib to len and dex for +1q (but not in Amp1q) in ENDURANCE, addition of elotuzumab to pomalidomide and dex, and bortezomib-based treatment before and after autologous stem cell transplantation (auto-SCT) vs no bortezomib (Table 2). Seven studies reported HR for patients with +1q in the trial (across both arms) compared to those without. In six studies (all studies other than SWOG1211), worse outcomes were seen with respect to OS and PFS for those with +1q versus without (Table 2). Important interventions for which subgroup analysis of +1q was not presented in trial results, and hence conclusions about the efficacy of the drugs specifically for patients with +1q cannot be ascertained included pomalidomide and ixazomib. Although subgroup analysis of various daratumumab trials has shown improvement for high-risk MM, the effect on gain1q was not isolated. Two recent contemporary trials that isolated effect of auto-SCT (DETERMINATION and IFM-2009) did not report +1q. However, in FORTE Trial, adverse prognostic implications of +1q were not seen in the arm receiving carfilzomib, len, dex and auto-SCT, indicating a possible role of carfilzomib and auto-SCT in ameliorating the adverse prognostic implications of +1q. Although len maintenance improved PFS after auto-SCT as maintenance in Myeloma XI overall for those with +1q, it did not appear to improve PFS for patients with isolated +1q (with no other concurrent genetic abnormalities). Conclusion: This systematic review of MM RCTs finds considerable heterogeneity in the reporting of +1q abnormalities in the literature, and +1q to be inconsistently classified as a poor prognostic factor in subgroup analysis of randomized myeloma trials. Most interventions that have shown to be successful in randomized trials and have clearly reported on the +1q subgroup have shown concordant direction of results and benefit of the applied intervention in the +1q subgroup. A more standardized approach to reporting of this abnormality is needed.

CONCLUSION The most widely used multiple myeloma (MM) staging system, the Revised International Staging System (R-ISS), is based on lactate dehydrogenase (LDH), albumin, high-risk genetic markers by FISH, and beta-2 microglobulin (B2M). However, it does not account for additional risk impacted by multiple genetic abnormalities, or the risk imparted by presence of gain of chromosome 1q, and most patients are staged as R-ISS Stage 2. Two new staging systems, the Mayo Additive Staging System (MASS), and the Second Revision of the International Staging System (R2-ISS) have been recently proposed. A comparison of the performance of these two systems has not previously been done. We aimed to externally demonstrate the application of these staging systems and compare their performances in a large, contemporary cohort of patients in the United States. We conducted a retrospective cohort study using the nationwide Flatiron Health electronic health record (EHR)-derived de-identified database, comprising de-identified patient-level structured and unstructured data, curated via technology-enabled abstraction and originating from approximately 280 US cancer clinics (~800 sites of care). The study included newly diagnosed MM patients initiating treatment between January 1, 2016 and October 1, 2022. We used the Kaplan-Meier method to evaluate real-world overall survival (rwOS) and patients were followed from first-line treatment initiation (index date) until the first of death, end of the study period or last recorded activity. The log-rank test to compare survival curves across derived stages. Multivariable analysis was conducted using stratified Cox models to account for non-proportional hazards by age with covariate adjustment for race/ethnicity, sex, practice type (academic or community) and diagnosis year (2016-2019 vs 2020-2022). Discrimination and calibration were evaluated in crude models using Harrell's c-index and the Hosmer-Lemeshow goodness-of-fit test, respectively. There were 497 patients with MM included. Patient characteristics are listed in Panel A. The distribution of patients across R-ISS stages were as follows, 24%, 63% and 13% for Stage 1, 2 and 3 respectively. rwOS differed across R-ISS stage (log-rank p = 0.0006) and the median OS (OS) was not reached (NR), 63, and 37 months for R-ISS stage 1, 2, and 3, respectively. 34%, 35% and 31% for MASS 1, 2, and 3, respectively. The corresponding survival curves were significantly different (p < 0.0001), with associated mOS of 77, 61 and 45 months for MASS stages 1, 2, and 3, respectively. R2-ISS includes four risk categories (stages I-IV) and in our cohort, 20% (n = 100) were stage I (low), 126 (25%) were stage II (low-intermediate), 229 (46%) were stage III (intermediate), and 42 (9%) were stage IV (high). Survival across stages were significantly different (p<0.0001), though the survival curves for low and low-intermediate, and intermediate-high and high, were clustered, suggesting comparable outcomes in stages I-II and stages III-IV. mOS for R2-ISS stages I, II, III, and IV was NR, 69, 50 and 51 months respectively (Panel B). In fully adjusted analyses, as compared to MASS I, the hazards of death were 2.0 (95% CI 1.3-3.2) for MASS II and 2.7 (1.7-4.2) for MASS III. The hazards of death were similar for R2-ISS low and low-int (HR for low-int vs low: 1.2 [0.7, 2.3]). As compared to R2-ISS low, the hazards of death were similarly higher for int-high and high (HRs: 2.4 [1.4, 4.1] and 2.6 [1.3, 5.2], respectively). Discrimination and calibration were similar across all staging systems (c = 0.6, and Hosmer-Lemeshow p>0.05 for all three staging systems). Application of contemporary MM staging systems in a large cohort of US patients shows that they are prognostic for OS in MM. MASS demonstrated a greater separation for OS across stages, whereas R2-ISS intermediate-high and high were largely overlapping. Although our results demonstrate similar accuracy and reliability of MASS and R2-ISS, the discrimination of patients across different stages seen with the newer staging systems, as opposed to R-ISS, calls for greater use of these newer staging systems in routine clinical practice.