Oral and Poster Abstracts
653. Myeloma: Therapy, excluding Transplantation: Poster II
Sunday, December 8, 2013, 6:30 PM-8:30 PM, Hall G (Ernest N. Morial Convention Center)
Background: Carfilzomib (Cfz) synergizes with lenalidomide and dexamethasone (Len-dex) to provide impressive response rates as upfront treatment of multiple myeloma (MM) (Jakubowiak et al 2012). The addition of clarithromycin to Len-dex has shown superior time to progression compared to Len-dex alone (Gay et al 2010). We hypothesized that sequential treatment with Cfz-dex and BiRD would lead to enhanced efficacy, response duration, and tolerability. We thus tested a sequential approach of upfront carfilzomib / dexamethasone, consolidation with BiRd, and lenalidomide maintenance to evaluate overall response and safety as first line therapy for MM.
Methods: Twenty-four patients (pts) with symptomatic untreated MM were enrolled in a single institution study to evaluate the efficacy and tolerability of Car-BiRd. Car-BiRd therapy is: Cfz IV over 30 minutes on Days 1, 2, 8, 9, 15, 16 of a 28-day cycle at a dose of 20mg/m2 on days 1, 2 of the 1st cycle only and 45mg/m2 for each successive dose thereafter and dex 40mg on D1, 8, 15, 22. Cfz-dex was continued until plateau in disease response defined as unchanged M-protein for 2 cycles. Elective autologous stem cell collection was then performed per physician and patient discretion and consolidation with BiRd initiated. Transplant ineligible pts proceeded directly to BiRd. BiRd is: Clarithromycin 500mg BID, lenalidomide 25mg daily on D1-21, and dex 40mg daily D1, 8, 15, 22 of 28-day cycle. Therapy was continued until a 2nd plateau in disease response after which lenalidomide maintenance at a dose of 10mg daily D1-21 of 28 day cycle was continued until disease progression or intolerability.
Results: 24 pts have currently been enrolled; 23 have completed at least 1 cycle of therapy and were evaluable for response. Sixteen pts (67%) harbored high-risk cytogenetics, as defined by the presence of one or more of the following on iFISH: del 17p, gain 1q, del 1p, t(4;14), t(14;16), or complex karyotypic abnormalities. Median study follow-up was 30.8 weeks (range 4.5-62.2). Response to the Car-BiRD regimen was: overall response rate (ORR) 87%, stringent complete response (sCR) 13%, very good partial response (VGPR) 48%, partial response (PR) 26%, stable disease (SD) 13%. Maximum response to the Cfz-dex induction was: ORR 87%, sCR 9%, VGPR 39%, PR 35%, SD 13%. Median time to PR and maximum response with Cfz-dex was 2 cycles (range 1-2) and 4 cycles (range 1-5) respectively. Median M-spike percentage decrease with Cfz-dex was 92% (range 13-100%). Twelve pts thereafter received BiRD consolidation with 5 pts (41%) further decreasing the M-spike by a median of 8% (range 1-45%). A median of 3 cycles (range 2-7) of BiRD was given until a 2nd response plateau was achieved. Seven pts subsequently received lenalidomide and all have maintained their response after a median of 5 cycles (range 1-8) of follow-up.
Seven pts (30%) have come off study, 2 (8%) secondary to disease progression (1 during Car-Dex and 1 during BiRD) and 5 pts (22%) due to toxicity (2 pts due to Grade III renal failure, both attributable to Cfz, and 2 pts due to Grade III CHF during Cfz-Dex, 1 attributable to Cfz; 1 pt with Grade III Thromboembolic event during BiRD, attributable to Len-dex).
Discussion: This is the first prospective study evaluating the response to induction Cfz/Dex in treatment-naïve MM. Cfz/Dex therapy appears safe and effective in newly diagnosed myeloma patients. Responses deepen with subsequent IMiD®-based consolidation and maintenance. Toxicities due to each component of the regimen were manageable. The ORR of 87% and rate of VGPR or better of 61% in group with a high percentage of unfavorable cytogenetics compares favorably to similar studies using 1st generation proteasome inhibitor combinations, and may continue to improve with longer study follow-up.