Efficacy and safety results with the combination therapy of arsenic trioxide, dexamethasone, and ascorbic acid in multiple myeloma patients: a phase 2 trial.

Background: Single-agent arsenic trioxide has shown promising results in patients with relapsed or refractory multiple myeloma (MM). Because preclinical data suggested greater activity with dexamethasone and ascorbic acid, a phase 2 trial of the combination of arsenic trioxide, dexamethasone, and ascorbic acid in patients with relapsed or refractory MM was conducted.

Methods: Twenty patients in whom no more than two previous therapies had failed were enrolled. The mean age was 62 yr, and 55% of the patients had refractory disease. The regimen consisted of 14- or 15-wk cycles, with the first cycle considered induction, followed by one or two consolidation cycles with a reduced steroid schedule and then a maintenance cycle in responding patients.

Results: The overall response rate was 30%, with at least stable disease in 80% of patients. Median progression- free survival was 316 d in all patients and 584 d in those with a response. The regimen was well tolerated, with most adverse events being mild or moderate.

Conclusions: This study showed the clinical efficacy and tolerability of the combination of arsenic trioxide, dexamethasone, and ascorbic acid. Further study is warranted.