Evaluating the effectiveness and safety of ixazomib-dexamethasone versus pomalidomide-dexamethasone combination for the treatment of patients with relapsed or refractory multiple myeloma.

This study evaluated the effectiveness and safety of ixazomib (Ninlaro)-dexamethasone (Decadron) (ixa-dex) versus pomalidomide (Pomalyst)-dexamethasone (pom-dex) combination for the treatment of patients with relapsed or refractory (r/r) multiple myeloma (MM). The data showed that ixa-dex was safe and as effective as pom-dex combination with manageable side effects in these patients.

Multiple myeloma (MM) is a type of cancer that comes from blood cells called plasma cells. A high number of patients with MM experience relapse (the tumor grows after treatment) or are refractory (not responsive to the treatment) to standard treatment. Currently, the treatment strategies for r/r MM are based on the different combinations of conventional drugs and novel drugs. One standard treatment combination for r/r MM is pomalidomide in combination with dexamethasone (pom-dex).

Maintenance therapy is usually recommended after first-line treatments to delay relapse or slow down cancer progression in patients. Common treatments for MM include proteasome inhibitors (PIs) such as ixazomib. Proteasomes are large molecules present in all body cells. They break down and remove damaged proteins. MM cells rely on proteasomes to multiply and spread. Ixazomib blocks the action of proteasomes, therefore preventing myeloma cells from growing and multiplying. Studies have shown ixazomib to be effective for the treatment of patients with newly diagnosed MM. However, the effectiveness and safety of ixa-dex versus pom-dex in previously treated patients with r/r MM are not known.

This study involved 122 patients with MM. All patients had been previously treated and either relapsed, or progressed after 2 or more lines of therapy. Patients were divided into 2 groups. Group 1 included 73 patients who received ixa-dex combination. Group 2 included 49 patients who received pom-dex combination. The average follow-up time was 15.3 months for group 1 and 17.3 months for group 2.

The overall average survival without cancer worsening in group 1 was 7.1 months compared to 4.8 months for group 2. This difference was not considered statistically significant.

In patients who previously received 2 or more lines of therapy, the average survival without cancer worsening in group 1 was 11 months compared to 5.7 months for group 2. In patients who previously received more than 3 lines of therapy, the average survival without cancer worsening in group 1 was 5.7 months compared to 3.7 months for group 2. 

The overall response rate (ORR; the partial or complete disappearance of the cancer) was 38% in group 1 versus 41% in group 2.

The number of patients experiencing severe side effects was similar between the 2 groups (51% in group 1 vs 53% in group 2). Quality of life was also similar between the 2 groups.

This study concluded that ixa-dex was safe and as effective as pom-dex combination with manageable side effects in previously treated patients with r/r MM.

This study was sponsored by Millennium Pharmaceuticals, Inc., the manufacturers of ixazomib. The sample size was very small. The patient population enrolled was older than anticipated. This study did not include data on genetic abnormalities in patients.