Clinical Outcomes of Patients with Newly Diagnosed Multiple Myeloma Receiving Triplet Therapy in the Connect MM® Disease Registry

Introduction: Triplet therapies are used for treatment (Tx) of both transplant-eligible and -ineligible patients (pts) with newly diagnosed multiple myeloma (NDMM). Actual patterns and outcomes of Tx are not fully understood. Connect MM® is the first and largest multicenter, US-based, prospective observational cohort study designed to characterize Tx patterns and outcomes for pts with NDMM. This analysis describes demographic and disease characteristics of pts who received triplet Tx as an induction regimen and for whom transplant was or was not intended. The analysis explores the relationship of these factors with overall survival (OS) and other efficacy endpoints.

Patients and Methods: Pts aged ≥ 18 y with NDMM within 60 days of diagnosis were eligible for enrollment regardless of disease severity, medical history, or comorbidities. Data including transplant intent (yes/no) was collected at baseline; follow-up data was collected quarterly thereafter. Based on the initial intent, 2 groups were identified: patients with intent to transplant who received transplant (TT) and pts with no intent to transplant who did not receive a transplant (NT). Triplet Tx was defined as the combination of ≥ 3 concurrent therapeutic agents in the first course of Tx (within 56 days of study entry). KM analysis adjusted for age was conducted for OS. Because decisions on use of transplant and triplet therapy are influenced by multiple factors, a multivariable Cox regression analysis was performed to evaluate the contribution of the triplet therapy (yes/no) to OS and was adjusted for other variables, including age, comorbidities, and ISS staging.

Results: Between September 2009 and December 2011, 1493 pts were enrolled. This analysis was on 1436 pts: 650 pts with transplant intent and 786 pts without transplant intent. The data cutoff date was November 30, 2014, and the median follow-up for overall survival (OS) was 33.8 mos. Of pts with transplant intent, 451 (69%) received transplant (TT) and 199 (31%) did not. Of pts without transplant intent, 62 (8%) received transplant and 724 (92%) did not (NT). The abstract focuses on TT and NT groups only.

NT pts tended to be older and have more advanced ISS staging and higher β₂-microglobulin levels than TT pts (Table). The most common triplet regimen given during the first course treatment (within 56 days) was lenalidomide, bortezomib, and dexamethasone (RVd). RVd was administered to 34% of the NT pts (76/225) and 59% of the TT pts (152/257). The most common non-triplet regimen was bortezomib and dexamethasone (Vd), which was given to 31% of NT pts (156/499) and 38% of TT pts (73/194).

Within the NT group, pts given triplet Tx had a lower risk of death than those who did not receive triplet Tx (P = .0013). The multivariable analysis found triplet Tx to be associated with a 36% reduced risk of death (hazard ratio [HR] = 0.64 [95% CI, 0.50-0.82]; P = .001). ISS disease stage (HR = 1.43 [95% CI, 1.21-1.69]; P < .001) and history of diabetes (HR = 1.38 [95% CI, 1.08-1.78]; P = .012) were negative prognostic factors for OS. Within the TT group, pts who received triplet Tx did not attain an OS benefit (P = .8993), and no baseline characteristics were significantly associated with OS. These results may be limited by other factors not considered that may have influenced physicians' choice of treatment, including the use of maintenance therapy and a short follow-up period of 33.8 months.

Conclusions: Triplet Tx as a first regimen is associated with longer OS in pts without transplant intent who did not receive a transplant. RVd and Vd were the most common first Tx regimens, respectively. Continued follow-up of these pts and enrollment of an additional cohort will provide additional data with mature follow-up.