Phase 2 study of arsenic trioxide in patients with relapsed or refractory multiple myeloma

Area of Science:

• Hematology
• Oncology
• Pharmacology

Background:

• Multiple myeloma (MM) remains a significant challenge, with patients often relapsing despite current treatments.
• There is a critical need for novel, non-cytotoxic salvage therapies for advanced MM.
• Arsenic trioxide, an established antitumour agent, has shown promising preclinical activity and preliminary clinical benefit in MM.

Purpose of the Study:

• To evaluate the efficacy and safety of arsenic trioxide as a single-agent salvage therapy in patients with relapsed or refractory multiple myeloma.
• To determine response rates, duration of response, and adverse events associated with arsenic trioxide treatment in this patient population.

Main Methods:

• A phase 2, multicentre, open-label study was conducted.
• Twenty-four patients with relapsed (n=8) or refractory (n=16) MM received arsenic trioxide at 0.25 mg/kg/day for 5 days/week over 2 weeks per 4-week cycle.
• Outcomes assessed included M-protein reduction, stable disease, time to response, duration of response, and toxicity.

Main Results:

• A reduction of 25% or more in serum M-protein levels was observed in 33% (8/24) of patients.
• An additional 25% (6/24) of patients achieved stable disease.
• The median time to response was 67.5 days, and the median duration of response was 130 days.
• Grade 3 or 4 neutropenia occurred in 16 patients.
• Arsenic trioxide therapy also led to lowered serum creatinine levels in two patients with high baseline values.

Conclusions:

• Arsenic trioxide demonstrates activity as a single-agent salvage therapy for patients with late-stage, relapsed, and refractory multiple myeloma.
• The agent is reasonably well tolerated, suggesting it is a viable option for patients with limited treatment alternatives.
• Further investigation into arsenic trioxide's role in MM treatment is warranted.