SUMMARY: The FDA on March 31, 2021, approved SARCLISA® (Isatuximab-irfc) 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. Multiple Myeloma is a clonal disorder of plasma cells in the bone marrow and the American Cancer Society estimates that in the United States, 34,920 new cases will be diagnosed in 2021 and 12,410 patients are expected to die of the disease. Multiple Myeloma (MM) in 2021 remains an incurable 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 median survival for patients with myeloma is over 10 years.
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® 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 present FDA approval was based on IKEMA trial, which 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 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).
At a prespecified interim analysis, and after a median follow up of 20.7 months, the PFS was Not Reached for SARCLISA® group versus 19.15 months for the KYPROLIS® and Dexamethasone group (HR=0.53; P=0.0007). This represented a 47% reduction in the risk of disease progression or death in patients treated with SARCLISA® plus KYPROLIS® and Dexamethasone, compared to those treated with KYPROLIS® and Dexamethasone. This benefit was seen across all patient subgroups including those with high risk cytogenetics. The Overall Response Rate did not differ significantly between the SARCLISA® combination and control groups (86.6% versus 82.9%), with Complete Response Rates of 39.7% versus 27.6% respectively. MRD negativity rate was 29.6% with SARCLISA® combination versus 13% in the KYPROLIS® and Dexamethasone group (P=0.0004). Overall survival data were not mature at the time of data cutoff.
It was concluded that the addition of SARCLISA® to KYPROLIS® and Dexamethasone, resulted in a superior, statistically significant improvement in PFS, with clinically meaningful improvement in depth of response. The authors added that SARCLISA® combination was well tolerated with manageable safety and a favorable benefit-risk profile, and represents a possible new standard of care treatment for patients with relapsed multiple myeloma.
Isatuximab Plus Carfilzomib and Dexamethasone Vs Carfilzomib and Dexamethasone in Relapsed/Refractory Multiple Myeloma (IKEMA): Interim Analysis of a Phase 3, Randomized, Open-Label Study. Moreau P, Dimopoulos MA, Mikhael J, et al. 2020 ASH Annual Meeting & Exposition. Abstract# 2316. Presented on December 6, 2020.
