SUMMARY: Multiple Myeloma is a clonal disorder of plasma cells in the bone marrow and the American Cancer Society estimates that in the United States, 34,470 new cases will be diagnosed in 2022 and 12,640 patients will die of the disease. Multiple Myeloma is a disease of the elderly, with a median age at diagnosis of 69 years and characterized by intrinsic clonal heterogeneity. Almost all patients eventually will relapse, and patients with a high-risk cytogenetic profile, extramedullary disease or refractory disease have the worst outcomes. The introduction of Proteasome Inhibitors, Immunomodulatory agents and CD 38 targeted therapies has resulted in higher Response Rates, as well as longer Progression Free Survival (PFS) and Overall Survival (OS), with the median survival for patients with myeloma approaching 10 years or more. Nonetheless, multiple myeloma in 2022 remains an incurable disease.
KYPROLIS® (Carfilzomib) is a second generation selective, epoxyketone Proteasome Inhibitor and unlike VELCADE® (Bortezomib), proteasome inhibition with KYPROLIS® is irreversible. CD38 is a transmembrane glycoprotein abundantly expressed on malignant plasma cells and with low levels of expression on normal lymphoid and myeloid cells. DARZALEX® (Daratumumab) is a human IgG1 antibody that targets CD38, and was approved for use in combination with KYPROLIS® and Dexamethasone in 2020, for the treatment of patients with multiple myeloma, who had received 1-3 prior lines of therapy. This was based on the CANDOR open label, Phase III trial, in which the triplet combination of DARZALEX®, KYPROLIS® and Dexamethasone resulted in a 37% reduction in the risk of progression or death, compared with KYPROLIS® and Dexamethasone. DARZALEX® exerts its cytotoxic effect on myeloma cells by multiple mechanisms, including Antibody Dependent Cellular Cytotoxicity (ADCC), Complement Mediated Cytotoxicity and direct apoptosis. Additionally, DARZALEX® may have a role in immunomodulation, by depleting CD38-positive regulator Immune suppressor cells, and thereby expanding T cells, in patients responding to therapy.
SARCLISA® (Isatuximab-irfc) is a CD38-targeting IgG1monoclonal antibody, similar to DARZALEX®, but unlike DARZALEX®, is not associated with complement activation, and can therefore be more readily given to patients with asthma or Chronic Obstructive Pulmonary Disease. Further, SARCLISA® targets a specific epitope on the CD38 receptor, and this distinction from DARZALEX® allows use of SARCLISA® in cases when DARZALEX® fails. Additionally, SARCLISA® infusions are less cumbersome. The FDA in 2021, approved SARCLISA® in combination with KYPROLIS® (Carfilzomib) and Dexamethasone, for the treatment of adult patients with Relapsed or Refractory multiple myeloma who have received one to three prior lines of therapy.
IKEMA trial is a multicenter, randomized, open label, Phase III study, in which the efficacy and safety of SARCLISA® in combination with KYPROLIS® and Dexamethasone was evaluated among patients with relapsed and/or refractory multiple myeloma, who had received 1-3 prior lines of therapy. In this study, 302 eligible patients were randomized 3:2 to receive SARCLISA® plus KYPROLIS® and Dexamethasone (N=179) or KYPROLIS® and Dexamethasone alone (N=123). SARCLISA® was given at 10 mg/kg IV weekly for 4 weeks and then every 2 weeks. KYPROLIS® was given at 20 mg/m2 IV on days 1 and 2 and then at 56 mg/m2 IV thereafter twice weekly for 3 of 4 weeks and Dexamethasone was given at 20 mg twice weekly. Treatment was continued until disease progression or unacceptable toxicity. The median age was 64 years, 23% had 3 or more prior lines of therapy, 90% of patients had prior treatment with Proteasome Inhibitor, 78% had prior treatment with Immunomodulatory drug (IMiD) and 24% had high-risk cytogenetics. The Primary endpoint was Progression Free Survival (PFS) as determined by an Independent Review Committee (IRC). Key Secondary endpoints included Overall Response Rate (ORR), rate of Very Good Partial Response (VGPR) or better, Complete Response (CR) rate, Minimal Residual Disease (MRD) negativity rate (10-5 by NGS), and Overall Survival (OS). The authors have now reported updated efficacy and safety results from IKEMA trial.
At a median follow-up of 44 months, the median PFS was 35.7 months in the SARCLISA® group and 19.2 months in the KYPROLIS® and Dexamethasone group (HR=0.58; 95.4% CI). The PFS benefit with SARCLISA® group was consistent across subgroups, including among patients with high-risk cytogenetics and those who were refractory to Lenalidomide. SARCLISA® plus KYPROLIS® and Dexamethasone also delayed the time to next treatment and prolonged PFS2. The median time to next treatment was 44.9 months with SARCLISA® combination and 25.0 months with KYPROLIS® and Dexamethasone (HR=0.55; 95% CI). The median PFS2 was 47.2 months and 35.6 months respectively (HR=0.68; 95% CI). The Complete Response (CR) rate or stringent CR rate was 44.1% in the SARCLISA® combination group and 28.5% in the KYPROLIS® and Dexamethasone group. MRD negativity was achieved in 33.5% of patients in the SARCLISA® combination group and 15.4% in the KYPROLIS® and Dexamethasone group. The rate of MRD negativity among patients with a CR or stringent CR was 26.3% in the SARCLISA® combination group and 12.2% in the KYPROLIS® and Dexamethasone group. No new safety signals were identified.
It was concluded that the addition of SARCLISA® to KYPROLIS® and Dexamethasone resulted in unprecedented median Progression Free Survival, Complete Response Rate and MRD negativity with a non-Lenalidomide regimen, and is the longest Progression Free Survival with a Proteasome Inhibitor backbone in the relapsed multiple myeloma setting. The authors added that SARCLISA® combination was well tolerated with manageable safety and a favorable benefit-risk profile, and this updated efficacy data support SARCLISA® in combination with KYPROLIS® and Dexamethasone as a standard of care treatment for patients with relapsed or refractory multiple myeloma.
VP5-2022: Updated progression-free survival (PFS) and depth of response in IKEMA, a randomized phase III trial of isatuximab, carfilzomib and dexamethasone (Isa-Kd) vs Kd in relapsed multiple myeloma (MM). Moreau P, Dimopoulos MA, Mikhael J, et al. ESMO Virtual Plenary. May 19-20, 2022. DOI:https://doi.org/10.1016/j.annonc.2022.04.013
