Challenging the concept of functional high-risk myeloma through transcriptional and genetic profiling.

Functional high-risk (FHR) multiple myeloma (MM) is defined as an unexpected, early relapse (ER) of disease in the absence of baseline molecular or clinical risk factors (RF), making FHR MM inherently dependent on which RFs were assessed at diagnosis, and what treatment patients received. To establish the true incidence of FHR, we analyzed uniformly treated, transplant-eligible patients from the Myeloma-XI (MyXI) trial that had been profiled for the International Myeloma Society and Working Group (IMS/IMWG) defined high-risk cytogenetic aberrations (HRCA), and the SKY92 gene expression HR signature (GEP-HR). A total of 135 MyXI patients were studied, with a median follow-up of 88 months; 25 (18.5%) experienced ER, defined as relapse <18 months from maintenance randomization post-autologous stem-cell transplantation. Hereof, 15 (60%) were IMS/IMWG-HR at diagnosis, of whom 8 were also GEP-HR. Another 6 patients were GEP-HR only and would have been missed by IMS/IMWG-HR. Among 4 patients with IMS/IMWG- and GEP-standard risk, 2 had isolated HR markers at diagnosis, leaving only 2 patients (8% of ER; 1.5% of all) truly meeting all FHR-criteria. Combined IMS/IMWG-HR and GEP-HR profiling identified 84% of ER, and differentiated long-term outcome across all 135 patients: co-occurring IMS/IMWG and GEP-HR was associated with very short overall survival compared to the absence of both (HR = 13.1; 95% CI, 6.5-26.1, P < .0001), followed by GEP-HR only (HR = 5.1; 95% CI, 2.4-11.1, P < .0001) and IMS/IMWG-HR only (HR = 3.2; 95% CI, 1.6-6.2, P = .0007). Our results support more comprehensive baseline diagnostic profiling to identify those at risk of ER upfront. The trials were registered at the ISRCTN Registry as ISRCTN49407852 and at clinicaltrials.gov as #NCT01554852.