BOSTON – Adding elotuzumab to lenalidomide and dexamethasone can prolong overall survival in patients with relapsed/refractory multiple myeloma, according to final results from the ELOQUENT-2 trial.
At a minimum follow-up of 6 years, elotuzumab plus lenalidomide/dexamethasone (ELd) reduced the risk of death by 18% and prolonged the median overall survival by 8.7 months when compared to treatment with lenalidomide/dexamethasone (Ld).
“The combination of elotuzumab with lenalidomide and dexamethasone demonstrated a statistically significant and clinically meaningful 18% reduction in the risk of death,” said Meletios A. Dimopoulos, MD, PhD, of the National and Kapodistrian University of Athens. “This treatment combination is the only approved antibody-based regimen shown to prolong overall survival significantly in patients with relapsed or refractory myeloma in the context of a large, prospective, randomized trial.”
Dr. Dimopoulos presented results from this phase 3 trial at the International Myeloma Workshop, held by the International Myeloma Society.
The final analysis ofincluded 646 patients with relapsed/refractory multiple myeloma who had received one to three prior lines of therapy at baseline. There were 321 patients randomized to ELd and 325 randomized to Ld. Baseline characteristics were well balanced between the treatment arms.
At the data cutoff of Oct. 3, 2018, 319 patients in the ELd arm and 316 in the Ld arm had received their assigned treatment. Ten percent (n = 33) of patients in the ELd arm and 4% (n = 14) in the Ld arm were still receiving their assigned treatment at the cutoff date.
The median number of treatment cycles was 19 (range, 9-42) in the ELd arm and 14 (range, 6-25) in the Ld arm. Most patients discontinued treatment due to disease progression (56% in the ELd arm and 57% in the Ld arm) or treatment-related toxicity (12% and 14%, respectively).
At a minimum follow-up of 71 months, the median overall survival was 48.3 months in the ELd arm and 39.6 months in the Ld arm. The hazard ratio was 0.82 (P = .0408).
The overall survival advantage with ELd was observed in all prespecified patient subgroups, Dr. Dimopoulos said. For example, overall survival favored ELd in patients aged 75 years and older (HR, 0.69), patients with International Staging System stage III disease at enrollment (HR, 0.74), those who had received two to three prior lines of therapy (HR, 0.71), and patients with del(17p) (HR, 0.71).
There were 212 deaths in the ELd arm and 225 in the Ld arm (67% and 71%, respectively). The most common causes of death were disease progression (41% in the ELd arm and 45% in the Ld arm), infection (9% and 6%, respectively), and “other” or unknown causes (7% and 9%, respectively). Two percent of patients in each arm (n = 7 in both) died from study treatment–related toxicity.
Dr. Dimopoulos pointed out that there were no imbalances in subsequent therapies between the ELd and Ld arms. The most common subsequent therapies (in the ELd and Ld arms, respectively) were bortezomib (38% and 42%), cyclophosphamide (30% in both arms), pomalidomide (26% and 29%), and lenalidomide (18% and 22%).
“Most of the adverse events which occurred throughout the study were due to the known side effects of lenalidomide and dexamethasone,” Dr. Dimopoulos said. “The contribution of elotuzumab to any kind of toxicity was minimal.”
Nearly all patients in both arms (99%) experienced adverse events. Serious adverse events were observed in 75% of patients in the ELd arm and 61% in the Ld arm. Adverse events leading to treatment discontinuation occurred in 36% and 33%, respectively, and grade 3-4 events leading to discontinuation occurred in 21% and 20%, respectively.
Grade 3-4 adverse events of special interest (in the ELd and Ld arms, respectively) were infections (35% and 27%), renal and urinary disorders (5% in both), cardiac disorders (6% and 8%), and lymphopenia (8% and 4%). Second primary malignancies occurred in 12% of patients in the ELd arm and 9% in the Ld arm.
This trial was sponsored by Bristol-Myers Squibb in collaboration with AbbVie. Dr. Dimopoulos reported relationships with Bristol-Myers Squibb, Amgen, Celgene, Janssen, and Takeda.
SOURCE: Dimopoulos MA et al. IMW 2019, .