Evaluating isatuximab for patients with recurrent or non-responding multiple myeloma

This study examined the effectiveness and safety of isatuximab plus PD (pomalidomide, dexamethasone) for patients with multiple myeloma (MM) that has come back or stopped responding to treatment. This study concluded that isatuximab was well-tolerated and significantly improved survival outcomes for these patients.

MM is a cancer of white blood cells. After initial treatment, some patients experience relapse (cancer recurrence) or develop disease that stops responding to treatment (refractory). Treatment remains challenging for these patients.

Isatuximab is a biological drug that directly targets cancer cells. Previous studies have shown that isatuximab was effective for patients with MM. Currently, pomalidomide, a targeted therapy, and dexamethasone, a steroid, are used together to treat patients with relapsed or refractory MM. It is unclear if adding isatuximab to this regimen improves outcomes for patients with relapsed/refractory MM. 

307 patients with relapsed or refractory MM were divided into 2 groups. 153 patients received PD and 154 patients received PD plus isatuximab (IPD). Patients were followed for an average of 11.6 months.

Isatuximab significantly delayed disease progression (tumor growth or spread). The average survival without cancer progression was 11.5 months in the IPD group and 6.5 months in the PD group. Patients in the IPD group had a 40.4% greater chance of surviving longer without cancer progression than the PD group. 

Isatuximab also increased the number of patients who responded to treatment. 60% of patients in the IPD group at least partially responded to treatment compared to 35% of patients in the PD group.

A separate analysis looked at whether patients had cancer that did not respond to drugs such as lenalidomide (Revlimid). These patients had a 40 to 50% increased chance of survival with IPD.  Isatuximab also increased patients’ chances of surviving longer by 31.3%.

More patients in the IPD group reported side effects than the PD group. The most common side effects were drug infusion reactions (38% vs. 0%), chest infections (28% vs. 17%), and diarrhea (26% vs. 20%). 

This study concluded that isatuximab was well-tolerated and significantly improved survival outcomes for patients with relapsed or refractory MM. The authors suggest that isatuximab is an important new treatment option for these patients.

The manufacturer of isatuximab, Sanofi, funded this study. Also, both physicians and patients knew which treatment group that patients were in, which may bias these results. More studies are needed to confirm these results.