Development of an Inclusive Risk Prognostic Index for Newly Diagnosed Multiple Myeloma
Authors: Derman Ben A , Belli Andrew J. , Wang Ching-Kun , Hansen Eric , Langerman Spencer S , Jakubowiak Andrzej , Chiu Brian C-H 
Published: November 2021

Background: Multiple myeloma (MM) risk stratification schemata such as the International Staging System (ISS) and Revised-ISS (R-ISS) were derived from clinical trial subjects made up predominately of younger White individuals with adequate renal function. It is unknown whether these prognostic indices are applicable to all patients with newly diagnosed (ND) MM, especially among Black individuals, older adults, and those with renal dysfunction. The R-ISS expanded on the ISS by including and serum lactate dehydrogenase (LDH) and high-risk cytogenetic abnormalities (HRCA) identified by fluorescence in-situ hybridization (FISH), but HRCA may not translate into poor prognosis for older adults and for Black individuals. We sought to create an inclusive risk prognostic index for NDMM using real-world data derived from electronic health records.

Methods: De-identified NDMM patient-level data in the real-world setting was provided by COTA, Inc. 3000 patients were identified who met the inclusion criteria of NDMM between 2005 and 2020. Baseline diagnostic parameters available within 60 days before or after diagnosis were included. Progression free survival (PFS) was defined as the time from diagnosis to disease progression or death of any cause. Overall survival (OS) was defined as the time from diagnosis to death of any cause. Proportional hazards models were used to calculate hazard ratios (HR) and 95% confidence intervals for all-cause mortality. Age-adjusted univariate analyses identified variables significantly associated with OS, and continuous variables were dichotomized based on accepted cutoffs. Multivariate Cox models to identify the variables with the strongest association with OS were performed adjusting for age, sex, Black race, receipt of proteasome inhibitor and immunomodulatory imide during induction, autologous stem cell transplant within 1 year of diagnosis, ECOG performance status, and creatinine. An additive risk score was created with one point given to each significant variable. The risk score was then validated for PFS using the Multiple Myeloma Research Foundation's (MMRF) CoMMpass database (version IA15).

Results: 3000 NDMM pts from the COTA, Inc. real-world database were initially evaluated, and a total of 689 NDMM pts had sufficient level of data to be included. The median follow-up time was 49.9 months (interquartile range (IQR) 29.1-76.2 months). Median age was 64 (IQR 32-86), including 44% age 65+. Of the 607 with reported race, 474 (78%) were White, 86 (14%) Black, 17 (3%) Asian, and 30 (5%) other. Of the 676 pts with reported serum creatinine (mg/dL), the median was 1 mg/dL (IQR 0.8-1.3) with 85 (13%) measuring &gt;2 mg/dL. Examined peripheral blood variables were: calcium (corrected for albumin), albumin&lt;3.5 mg/dL, beta2-microgloublin (B2M) &gt;3.5 mcg/mL, LDH &gt;250 U/L, hemoglobin &lt;10 g/dL, M-spike &gt;3 g/dL, and IgA isotype. Variables with significance using multivariate analysis at p&lt;0.1 were: LDH&gt;250 U/L, B2M &gt;3.5 mcg/mL, hemoglobin &lt;10 g/dL, and IgA isotype. These variables were simultaneously present in 558 patients. Patients were stratified into 3 groups: standard (std score = 0, n=186), intermediate (int score = 1-2, n=295), and high (score 3-4, n=77) risk. For this inclusive risk prognostic index (IRPI), the c-statistic was 0.61 for OS (HR 2.0, 95% CI 1.5-2.6, p&lt;0.001) which compared favorably to the c-statistic for ISS (c=0.64, HR 1.8, 95% CI 1.5-2.2, p&lt;0.001) and for R-ISS (c=0.63, HR 2.0, 95% CI 1.6-2.6). For the IRPI, median OS was 218 (std) vs 121.5 (int) vs 79.5 months (high). In comparison, median OS by ISS was 198.9 (stage I) vs 121.6 (stage II) vs 80.6 months (stage III), and by R-ISS: 198.9 (I) vs 121.6 (II) vs 79.5 months (III).

Validation of the inclusive risk prognostic index (IRPI) using the MMRF CoMMpass database in 938 patients with all four criteria showed median PFS was 44 (std) vs 33 (int) vs 20.5 months (high). In comparison, median PFS by ISS was 45.9 (I) vs 31.5 (II) vs 20.5 (III) months. Median PFS by R-ISS was 50.1 (I) vs 32.7 (II) vs 19.1 (III) months.

Conclusions: Employing real-world datasets that incorporate a more diverse patient population led to the generation of an inclusive risk prognostic index incorporating beta2-microgloublin, LDH, hemoglobin, and IgA isotype. This IRPI does not require bone marrow sampling, performs similarly to ISS and R-ISS in predicting PFS, and with datasets with longer follow-up may prove to predict OS.

Figure 1 Figure 1.

Disclosures

Derman: Sanofi: Membership on an entity's Board of Directors or advisory committees. Belli: COTA, Inc.: Current Employment, Other: Equity ownership. Wang: COTA, Inc.: Current Employment, Other: Equity ownership. Hansen: COTA, Inc.: Current Employment. Jakubowiak: Amgen: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Gracell: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.