Patients with high-risk smoldering multiple myeloma (SMM) have a 50% risk of progression to overt disease within 2 years. These patients have relatively strong immune systems compared with patients with more advanced myeloma; hence, the rationale to study immunotherapy in this population.
This phase 2 study aimed to determine the clinical benefit of early therapeutic intervention with the combination of elotuzumab, lenalidomide, and dexamethasone in patients with high-risk SMM.
Patient eligibility was determined based on recently defined criteria for high-risk SMM.1 All enrolled patients received weekly elotuzumab (10 mg/kg) on days 1, 8, 15, and 22 for the first two 28-day cycles; lenalidomide on days 1 to 21; and dexamethasone 40 mg on days 1, 8, and 15. Patients were then allowed to continue on maintenance therapy with elotuzumab and lenalidomide.
A total of 51 patients were enrolled in this study. The median age of patients was 63 years, and the median number of cycles completed was 8 (range, 1-23). Of 47 evaluable patients, the overall response rate was 82.6%, including 2 complete responses, 6 very good partial responses, and 11 partial responses. The clinical benefit rate was 100%. Data showed that high-dose dexamethasone does not have a detrimental effect on the immune system in patients with SMM. Thus far, no patients have progressed to active multiple myeloma at 24 months of study.
Most commonly occurring treatment-related grade 3 toxicities included hypophosphatemia, neutropenia, decreased lymphocyte count, hypertension, pulmonary infection, and hypokalemia.
Researchers concluded that the combination of elotuzumab, lenalidomide, and dexamethasone is very well tolerated among patients with high-risk SMM. The high response rates seen in this otherwise untreated population suggest that early therapeutic intervention is worthy of consideration in patients with high-risk SMM.
Ghobrial IM, et al. ASH 2016. Abstract 976.