Depth of response and response kinetics of isatuximab plus carfilzomib and dexamethasone in relapsed multiple myeloma

Carfilzomib, daratumumab, and dexamethasone (KdD) vs. lenalidomide-sparing pomalidomide-containing triplet regimens for relapsed/refractory multiple myeloma: an indirect treatment comparison

Nearly all patients with multiple myeloma eventually relapse or become refractory to treatment. Lenalidomide is increasingly administered in the frontline until disease progression or intolerance to therapy, resulting in the need for highly effective, lenalidomide-sparing options. In this study, carfilzomib plus daratumumab and dexamethasone were evaluated against lenalidomide-sparing, pomalidomide-containing triplets using matching-adjusted indirect comparison in the absence of head-to-head data. The analyses utilized long-term follow-up data from the CANDOR study (NCT03158688). Treatment with carfilzomib, daratumumab, and dexamethasone resulted in significantly longer progression-free survival (hazard ratio 0.60 [95% confidence interval: 0.37, 0.88])vs. pomalidomide plus bortezomib and dexamethasone, and numerically longer progression-free survival (hazard ratio 0.77 [95% confidence interval: 0.50, 1.08]) vs. daratumumab plus pomalidomide and dexamethasone in patients with relapsed/refractory multiple myeloma and previous lenalidomide exposure, the majority of whom were lenalidomide refractory. Carfilzomib plus daratumumab and dexamethasone offers a highly effective, lenalidomide-sparing treatment option for this population.

A sensitive high-resolution mass spectrometry method for quantifying intact M-protein light chains in patients with multiple myeloma

To determine the disease status and the response to treatment for patients with multiple myeloma, measuring serum M-protein levels is a widely used alternative to invasive punctures to count malignant plasma cells in the bone marrow. However, the quantification of this monoclonal antibody, which varies from patient to patient, poses significant analytical challenges. This paper describes a sensitive and specific mass spectrometry assay that addresses two objectives: to overcome the potential interference of biotherapeutics in the measurement of M-proteins, and to determine the depth of response to treatment by assessing minimal residual disease. After immunocapture of immunoglobulins and free light chains in serum, heavy and light chains were dissociated by chemical reduction and separated by liquid chromatography. M-proteins were analyzed by high-resolution mass spectrometry using a method combining a full MS scan for isotyping and identification and a targeted single ion monitoring scan for quantification. This method was able to discriminate M-protein from the therapeutic antibody in all patient samples analyzed and allowed quantification of M-protein with a LLOQ of 2.0 to 3.5 µg/ml in 5 out of 6 patients. This methodology appears to be promising for assessing minimal residual disease with sufficient sensitivity, specificity, and throughput.

Final analysis of carfilzomib, dexamethasone, and daratumumab vs carfilzomib and dexamethasone in the CANDOR study

CANDOR (NCT03158688) is a phase 3, randomized, open-label trial comparing carfilzomib, daratumumab, and dexamethasone (KdD) vs carfilzomib and dexamethasone (Kd) in adults with relapsed/refectory multiple myeloma (RRMM) with 1 to 3 prior therapies. The CANDOR study met its primary end point of progression-free survival (PFS) in the primary analysis. Here, we report the final analysis of the study, including secondary end points and subgroup analyses thereof. The median follow-up was 50 months. Patients treated with KdD had higher minimal residual disease-negative (MRD-) achievement rates (28% vs 9%; odds ratio [OR], 4.22; 95% confidence interval [95% CI], 2.28-7.83) and MRD- complete response rates (22% vs 8%; OR, 3.55; 95% CI, 1.83-6.88) than those treated with Kd. Median PFS was 28.4 months for KdD vs 15.2 months for Kd (hazard ratio [HR], 0.64; 95% CI, 0.49-0.83). Median overall survival (OS) for KdD was 50.8 months vs 43.6 months for Kd (HR, 0.78 [0.60-1.03]; P = .042). Trends toward improved OS occurred in predefined subgroups, including patients refractory to lenalidomide (KdD, not reached vs Kd, 38.2 months; HR, 0.69 [0.43-1.11]) and refractory to proteasome inhibitor (KdD, 43.2 months vs Kd, 30.0 months; HR, 0.70 [0.45-1.09]), and there was significant improvement in patients with high-risk cytogenetics (KdD, 34.3 months vs Kd: 17.1 months; HR, 0.52 [0.29-0.94]). No new safety signals were identified. In summary, the final analysis of CANDOR confirmed the PFS benefit and showed a trend in OS benefit with KdD vs Kd. These findings reinforce KdD as a standard of care for RRMM, especially in clinically relevant patient subgroups. This trial was registered at www.clinicaltrials.gov as #NCT03158688.

Isatuximab in the Treatment of Multiple Myeloma: A Review and Comparison With Daratumumab

Multiple myeloma (MM) is a hematologic malignancy characterized by the proliferation of clonal plasma cells. Although advances in treatment have markedly improved survival outcomes for patients with MM, this disease is still considered incurable owing to its high incidence of relapse and refractoriness. Isatuximab is an anti-CD38 monoclonal antibody that can induce apoptosis in myeloma cells through a variety of mechanisms. Many clinical studies have demonstrated the efficacy and efficiency of isatuximab in both relapsed/refractory multiple myeloma (RRMM) and newly diagnosed multiple myeloma, leading to its approval for the treatment of adults with RRMM in combination therapies. In this review, the structure, mechanisms of action, pharmacokinetics, pharmacogenetics, and safety profile of isatuximab in MM are summarized. Additionally, isatuximab is compared with daratumumab in terms of mechanism and efficacy.