Posted: Monday, July 10, 2023
Treatment with the anti-CD38 monoclonal antibody isatuximab-irfc plus lenalidomide demonstrated a “high” overall response rate without worsening the well-being of patients with high-risk smoldering multiple myeloma, based on the results of the multicenter phase II ISAMAR trial presented during the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 8046). Additionally, Elisabet Esteve Manasanch, MD, of The University of Texas MD Anderson Cancer Center, Houston, and colleagues reported prolonged progression-free survival with isatuximab monotherapy versus historical data.
“The results of this study give rationale for the ongoing phase III ITHACA [trial] evaluating isatuximab [with and without] lenalidomide and dexamethasone, with the potential to change the standard of care in high-risk smoldering multiple myeloma,” the investigators concluded.
Patients were administered isatuximab alone (n = 25) or in combination with lenalidomide (n = 36). After six cycles of therapy, in those treated with lenalidomide, the overall response rate was 89%. A total of 47% of this population experienced a grade 3 treatment-related adverse event. Decreased absolute neutrophil count (56%), decreased white blood cell count (53%), decreased absolute lymphocyte count (42%), fatigue (39%), diarrhea (39%), skin rash (28%), thrombocytopenia (28%), and constipation (28%) were the most frequently reported grade 1 and 2 adverse events. No grade 5 adverse events nor adverse event–related treatment discontinuations were documented.
Treatment with isatuximab plus lenalidomide was found to increase the CD4/CD8-positive and effector memory cytotoxic T-cell counts in the bone marrow tumor microenvironment. Based on a quality-of-life analysis, compared with baseline levels, both the patients treated with and without lenalidomide showed decreased cancer worry or anxiety and an improved future perspective at 6 months. The investigators noted that quality of life was favorable and conserved throughout treatment. The median durations of progression-free and overall survival were not reached with lenalidomide, whereas they were 49.3 months and not reached, respectively, with isatuximab monotherapy.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.