Treatment outcome with the combination of carfilzomib, lenalidomide, and low-dose dexamethasone (CRd) for newly diagnosed multiple myeloma (NDMM) after extended follow-up

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Background: We previously reported results from a phase 1/2 trial of CRd in NDMM (NCT01029054), demonstrating a high rate (42%) of stringent complete response (sCR) and overall favorable efficacy /safety after a median of 12 cycles of treatment (tx) and a median follow-up of 13 mo (Jakubowiak et al Blood, 2012). Here we report updated results after extended tx and additional 12 mo of follow-up. Methods: Patients (pts) received 28-day (d) cycles of carfilzomib (CFZ) 20–36 mg/m2 IV (d1, 2, 8, 9, 15, 16), lenalidomide (LEN) 25 mg PO (d1–21), and dexamethasone 40/20 mg PO wkly (cycles 1–4/5–8). For cycles 8–24, CRd was given with a modified CFZ schedule (d1, 2, 15, 16) and then LEN alone after cycle 24. Stem cell transplant was an option after cycle 4. Response was assessed by IMWG plus nCR. Results: As of Nov 2012, 53 pts had received a median of 22 CRd cycles (range 2–24); 7 pts opted for transplant; 24 continued LEN maintenance for median 8 mo (range 1–10). Median follow-up was 25 mo (range 5–37). With extended tx, the CR rate was 64%; sCR improved from 42% to 53%, ≥nCR from 62% to 72%, and ≥VGPR from 81% to 87% (follow-up 13 vs 25 mo); ≥PR remained at 98%. Immunophenotypic CR (IMWG) was achieved in 22/26 evaluated pts. Of pts in sCR, 25% had high-risk cytogenetics per IMWG. In pts who did not proceed to transplant (n=46), the sCR was 59%, CR 70%, ≥nCR 78%, ≥VGPR 91%, and ≥PR 100%. Over the course of tx, depth of response improved. Median time to ≥VGPR was 4 cycles (range 2–17), ≥nCR 4.5 cycles (range 2–15), and sCR 10 cycles (range 4–30); 2 pts converted to sCR during LEN maintenance. At 2 years, the estimated PFS rate was 94% and OS was 98%; for pts with sCR, rates were 96% and 100%, respectively. Adverse event types, rates, and dose modifications during extended tx were comparable with those previously reported. There was 1 death off study due to disease progression. Conclusions: Extended follow-up showed that depth of response continued to improve over the course of prolonged CRd tx, resulting in exceptional CR, sCR, and PFS. Extended tx continued to be well tolerated. The results compare favorably with historical studies in both transplant and non-transplant NDMM. Clinical trial information: NCT01029054.

Stringent complete response (sCR) in patients (pts) with newly diagnosed multiple myeloma (NDMM) treated with carfilzomib (CFZ), lenalidomide (LEN), and dexamethasone (DEX)

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Background: Combination treatment (tx) with CFZ, LEN, and DEX (CRd) is well tolerated and highly active in NDMM. In a phase 1/2 study, CRd provided rapid reduction of disease by 68% after cycle (C) 1 and 94% ≥partial response (PR) at a median of 8C, including 65% ≥very good PR and 53% ≥near CR (nCR), which improved to 79% ≥nCR after C12 (ASH 2011, Abstr 631). Here, we examine the clinical significance of the response rates with longer follow-up. Methods: Pts with NDMM were treated in 28-day (d) C with CFZ 20–36 mg/m2 IV (d1, 2, 8, 9, 15, 16), LEN 25 mg PO (d1–21) and DEX 40/20 mg PO weekly (C1–4/5–8). After C4, autologous stem cell transplant (ASCT) candidates achieving ≥PR could collect stem cells but then continued CRd with the option to proceed to ASCT. After C8, pts received CRd maintenance, using the last tolerated doses, with LEN/DEX at the same schedule but a modified CFZ schedule (d1, 2, 15, 16). Response was assessed by IMWG criteria plus nCR. Results: As of Nov 30, 2011, median follow-up was 14 mo (range 4–25) with 33/53 (62%) pts achieving ≥nCR and 42% sCR. After a median of 13C (range 1–25), 36 pts completed C8 and continued CRd maintenance, 64% achieving sCR. 20/22 pts in CR evaluated for minimal residual disease (MRD) by multiparameter flow cytometry had no MRD. Progression-free survival (PFS) rate was 97% at 12 and 92% at 24 mo. All pts who achieved sCR have maintained response for a median of 9 mo (range 1–20). Extended CRd tx was well tolerated. During CRd maintenance, the most common toxicities (all grades) were lymphopenia (30%), leukopenia (26%), and fatigue (25%), and peripheral neuropathy remained limited (11%, all G1/2). There were no tx discontinuations due to toxicity during maintenance and limited dose modifications (CFZ 19%, LEN 28%, DEX 31%). Conclusions: CRd is highly active in NDMM, providing rapid and deep responses. Extended tx was well tolerated and resulted in improved depth of response with a high sCR rate and a significant proportion of pts without evidence of MRD. Responses were durable with very promising PFS. All pts who achieved sCR remained on CRd with sustained sCR. These results compare favorably to other frontline regimens.

Discordance between serum cardiac biomarker and immunoglobulin-free light-chain response in patients with immunoglobulin light-chain amyloidosis treated with immune modulatory drugs

We evaluated the capability of soluble cardiac biomarkers to predict tolerability and outcomes of IMiD-containing treatments among 106 patients treated on clinical trials. Baseline elevations in troponin T (TnT) and N-terminal brain naturietic protein (NT-proBNP) predicted for an inability to tolerate IMiD-based regimens. The best predictors for early attrition during cycle 1 were TnT ≥ 0.07 μg/L and NT-proBNP ≥ 11,939 ng/L. NT-proBNP-response underperformed TnT-response as a predictor for overall survival (OS), but both predicted for early protocol attrition. Despite hematologic response, IMiD-treated patients were at higher risk for NT-proBNP rises and early drug discontinuation than a control population but not for early death. These observations prompt two questions: (1) does IMiD-based therapy lead to increased fluid retention and/or cardiac toxicity and (2) is an NT-proBNP-driven cardiac response system valid in IMiD-treated amyloidosis patients? Recognition of potential drug-induced cardiac toxicity is important so that increased cardiac surveillance and drug dose-adjustment or discontinuation may be implemented.

Long-term results of single-agent thalidomide as initial therapy for asymptomatic (smoldering or indolent) myeloma

We report the long-term follow-up results of a phase II trial of thalidomide for early-stage multiple myeloma (MM). Patients were eligible if they had smoldering multiple myeloma (SMM) or indolent MM without the need for immediate therapy. Thalidomide was initiated at a dose of 200 mg/day and adjusted as tolerated. Disease progression was defined using modified American Society of Hematology/Food and Drug Administration consensus panel criteria for SMM. Thirty-one patients were enrolled; 29 (19 SMM and 10 indolent MM) were eligible. The median age was 61 years. Median follow-up of living patients was 10.2 years (range, 7.5-11.0 years). Ten patients (34%) had a partial response (PR) and nine had minimal response (MR) for an MR plus PR rate of 66%. The median time to progression (TTP) to symptomatic myeloma was 35 months. Median TTP was 61 months in those achieving PR, 39 months with MR, and 9 months among those failing to achieve either MR or PR, P = 0.005. Median overall survival from diagnosis was 86 months; median survival from onset of symptomatic myeloma was 49 months. Grade 3-4 nonhematologic adverse events were noted in 55% of patients. Randomized trials are needed to determine the role of early therapy in SMM.