Evaluating the effectiveness and safety of ixazomib as maintenance therapy after bortezomib-based induction therapy in real-world patients with multiple myeloma.

This study evaluated the effectiveness and safety of ixazomib (Ninlaro) as maintenance therapy after bortezomib (Velcade)-based induction therapy in real-world patients with multiple myeloma (MM). The data showed that the outcomes of these patients in the real-world setting were good with manageable side effects.

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. 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 bortezomib and 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. Bortezomib and ixazomib block the action of proteasomes, therefore preventing myeloma cells from growing and multiplying. Maintenance therapy with bortezomib can improve outcomes of patients with MM, however, side effects like nerve damage and pain in the hands and feet limit its long-term use. Studies have shown ixazomib to be effective for the treatment of patients with newly diagnosed MM. However, the effectiveness and safety of ixazomib as maintenance therapy after bortezomib-based induction therapy in real-world patients with MM is not known.

This study involved 71 patients with MM. Patients were divided into 2 groups. Group 1 included 37 patients with newly diagnosed MM. Group 2 included 34 patients with relapsed and/or refractory MM (RRMM). All patients received bortezomib-based treatment as first-, second- or third-line therapy. Then all patients received ixazomib maintenance therapy. The average follow-up time was 26.5 months.

After an average of 9 cycles of bortezomib-based induction therapy, the overall response rate (ORR; the partial or complete disappearance of the cancer) was 81.7%. 47.9.% of the patients achieved a very good partial response.

After an average of 6 cycles of ixazomib-based maintenance therapy, the ORR was 74.6%. 54.9.% of the patients achieved a very good partial response. Of these, 25.4% of the patients achieved a deepened response.

The overall average survival without cancer worsening in group 1 was 28.4 months and 16.2 months for group 2. After ixazomib-based maintenance, the average survival without cancer worsening in group 1 was 16.5 months and 10 months for group 2.

The most common side effects after ixazomib maintenance therapy were diarrhea (23.9%) and a low white blood cell count (12.7%). 11.2% of the patients experienced severe side effects. 

This study concluded that ixazomib as maintenance therapy after bortezomib-based induction therapy was effective with manageable side effects in real-world patients with MM.

This study looked back in time at medical records. The sample size was very small. The study only included patients from a single institution in China. Larger studies at different institutions are needed to validate the findings.