Triplet Outperforms Doublet in Relapsed/Refractory Multiple Myeloma

Adding cyclophosphamide to pomalidomide and dexamethasone can improve progression-free survival (PFS) in Asian patients with relapsed or refractory multiple myeloma, according to a study presented at the ASH Annual Meeting 2023.

The study is part of the Asian Myeloma Network’s goal to evaluate low-cost treatment combinations that are relevant to Asian populations, said Wee-Joo Chng, MBBS, PhD, of the National University Cancer Institute in Singapore, who presented the research.

This phase 3 trial included 122 patients with relapsed or refractory multiple myeloma who had prior exposure to proteasome inhibitors and immunomodulatory agents. The patients were randomly assigned to receive cyclophosphamide plus pomalidomide and dexamethasone (n=62) or pomalidomide and dexamethasone (n=60).

Baseline characteristics were similar between the arms. In both arms, patients had received a median of 3 prior lines of therapy (range, 1-6). The most common prior treatments (in the triplet and doublet arms, respectively) were lenalidomide (98.4% vs 100%), bortezomib (75.8% vs 76.7%), thalidomide (54.8% vs 46.7%), cyclophosphamide (46.8% vs 31.7%), and autologous hematopoietic stem cell transplant (43.5% vs 40.0%).

At a median follow-up of 13.5 months, the median PFS was significantly longer in the cyclophosphamide arm. The median PFS was 10.9 months in the triplet arm and 5.8 months in the doublet arm (hazard ratio [HR], 0.43; 95% CI, 0.27-0.69; P <.001).

The difference in overall survival between the treatment arms was not statistically significant (HR, 0.76; 95% CI, 0.36-1.58; P =.464). The median overall survival was 41.5 months in the triplet arm and 27.5 months in the doublet arm.

The overall response rate was 61.3% in the triplet arm and 38.3% in the doublet arm. The rate of stringent complete response was 6.5% and 0%, respectively. The rate of complete response was 11.3% and 3.3%, respectively. The median duration of response was 12.0 months and 5.7 months, respectively (HR, 0.41; 95% CI, 0.20-0.87; P =.021).

The most common grade 3-4 treatment-emergent adverse events (in the triplet and doublet arms, respectively) were neutropenia (37.1% vs 21.7%) and pneumonia (12.9% vs 13.3%).

There were 17 deaths in each arm, but most were due to disease progression. There was 1 treatment-related death in the triplet arm and 2 in the doublet arm. Two deaths were due to infections, and 1 was due to fluid overload.

“The [cyclophosphamide-pomalidomide-dexamethasone] regimen is well tolerated and represents an excellent oral-based therapeutic option in this heavily pretreated Asian myeloma population,” Dr Chng concluded.

Disclosures: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.

This article originally appeared on Cancer Therapy Advisor