Randomized phase 2 trial of ixazomib and dexamethasone in relapsed multiple myeloma not refractory to bortezomib

Area of Science:

• Oncology
• Pharmacology
• Clinical Trials

Background:

• Proteasome inhibitors are crucial in multiple myeloma treatment.
• Optimizing proteasome inhibition while minimizing toxicity is a key therapeutic goal.
• Ixazomib is the first oral proteasome inhibitor available for clinical use.

Purpose of the Study:

• To evaluate the efficacy and toxicity of ixazomib combined with dexamethasone in patients with relapsed multiple myeloma.
• To compare two different weekly doses of ixazomib (4 mg vs. 5.5 mg) in combination therapy.

Main Methods:

• A randomized clinical trial involving 70 patients with relapsed multiple myeloma.
• Patients were assigned to receive either 4 mg or 5.5 mg of ixazomib weekly for 3 weeks of a 4-week cycle, combined with 40 mg of dexamethasone weekly.
• Outcomes assessed included response rates, event-free survival (EFS), overall survival, and adverse events.

Main Results:

• An overall response rate of 43% was observed. The 5.5 mg ixazomib dose group showed a higher response rate (54%) compared to the 4 mg group (31%).
• Median event-free survival (EFS) was 8.4 months for the entire cohort. EFS was shorter in patients previously treated with bortezomib (5.7 months) versus bortezomib-naïve patients (11.0 months).
• Grade 3 or 4 treatment-related adverse events occurred in 32% of patients on the 4 mg dose and 60% on the 5.5 mg dose, with more dose reductions at the higher dose.

Conclusions:

• Ixazomib combined with dexamethasone demonstrates good efficacy in relapsed multiple myeloma.
• The 5.5 mg dose of ixazomib resulted in a higher response rate but was associated with increased toxicity and dose reductions.
• The combination therapy is generally well-tolerated, offering a viable treatment option for relapsed myeloma patients.