Adding Venetoclax to Treatment Regimen of Patients with Multiple Myeloma

Shaji Kumar, MD

Final overall survival results of a Phase 3 study were presented at the American Society of Hematology (ASH) 2021 conference. The BELLINI study compared venetoclax with placebo in combination with bortezomib and dexamethasone in relapsed/refractory multiple myeloma patients.

BELLINI was a Phase 3, randomized, double-blind, multicenter study that included patients who had received 1-3 prior lines of therapy and were either sensitive or naive to proteasome inhibitors.

Progression-free survival was assessed by an independent review committee as the primary endpoint. Overall response rate and overall survival were secondary endpoints.

A team of investigators led by Shaji K Kumar, MD, Division of Hematology, Department of Internal Medicine, Mayo Clinic, discovered that the addition of venetoclax to bortezomib and dexamethasone significantly improved progression-free survival.

However, this combination also showed an increased mortality when compared with the placebo group.

Patients with t(11;14) or high BCL2, with a favorable benefit-risk profile, displayed the greatest progression-free survival improvement when venelotax was added to bortezomib and dexamethasone, which was in line with previous analyses.

Venetoclax is a highly selective, potent, oral BCL-2 inhibitor that induces apoptosis in multiple myeloma cells. Previous data have shown promising results when venetoclax is combined with bortezomib and dexamethasone in patients with relapsed/refractory multiple myeloma.

The Results

Investigators randomized 291 patients into a venetoclax group (194) and a placebo group (97). By March 15, 2021, the final overall survival data cutoff, 28 patients were receiving ongoing venetoclax treatment, and 5 patients were receiving placebo treatment.

Data from a median follow-up of 45.6 months reported that in the venetoclax group there were 78 (40%) deaths compared with 36 (37%) in the placebo group.

The median progression-free survival among all patients per investigator was 23.4 months in the venetoclax arm and 11.4 months in the placebo arm (HR, 0.58 [95% CI, 0.43-0.78]).

As for patients with t(11;14), the venetoclax arm median progression-free survival was 36.8 months compared with 9.3 months in the placebo arm (HR, 0.12 [95% CI, 0.03-0.44]).

Patients who had high BCL2 and were treated with venetoclax had a median progression-free survival of 30.1 months and 9.9 months in the placebo group (HR,0.37 [95% CI, 0.21-0.64]).

Median overall survival rate was not reached in the venetoclax or placebo arm among all patients, patients with t(11;14), patients with high BCL2, and patients with t(11;14) or high BCL2.

The Adverse Events

Investigators reported that the most common treatment-emergent adverse events with venetoclax compared to placebo included diarrhea, nausea, and constipation. Thrombocytopenia, neutropenia, pneumonia, anemia, and diarrhea, were the prominent Grade 3/4 adverse events.

When the venetoclax group was compared to the placebo group, serious adverse events occurred in 57% of venetoclax patients and 55% of placebo patients. Serious infections and infestations occurred in 35% and 29% of patients, respectively.

The amount of patients that discontinued treatment due to adverse events was 26% in the venetoclax group and 11% in the placebo group.

In the venetoclax group, 12 deaths were due to adverse events, with 9 of them caused by serious infection. The placebo group had 1 death due to adverse events.

Treatment-emergent deaths totaled 16, or 6%. Of these deaths, 3 were due to disease progression, 14 (7%) deaths occurred in the venetoclax group while 2 (2%) occurred in the placebo group.