Interim results of a phase III trial suggest an innovative immune-based therapy may offer a new option for patients with relapsed multiple myeloma.

The new monoclonal antibody elotuzumab, added to standard lenalidomide and dexamethasone therapy, extended the duration of remissions by about five months, on average, compared to standard treatment alone.

“It appears that, for patients with relapsed multiple myeloma who would otherwise be offered lenalidomide and dexamethasone, addition of this new targeted drug makes the outcomes even better,” said lead study author Sagar Lonial, MD, Chief Medical Officer of the Winship Cancer Institute of Emory University, and professor and executive vice chair of the Department of Hematology and Medical Oncology of Emory University School of Medicine in Atlanta, USA.

“It was particularly striking that the difference between the elotuzumab and control groups seems to get bigger over time, which really speaks to the power of this immune-based approach.”

Elotuzumab attaches to a cell surface protein called SLAMF7, which is found on myeloma cells and on a type of immune cells known as natural killer (NK) cells.

Scientists believe that elotuzumab mounts a two-pronged attack on cancer by targeting myeloma cells directly and by enhancing the NK cells’ ability to kill myeloma cells.

Currently, there are no monoclonal antibodies approved for treatment of multiple myeloma.

This is the largest study of a monoclonal antibody in multiple myeloma and the first phase III trial demonstrating benefit using a targeted immune-based approach to treating the disease.

In the study, 646 patients with recurrent multiple myeloma were randomly assigned to receive lenalidomide and dexamethasone (control group) or lenalidomide and dexamethasone with elotuzumab.

At a median follow-up period of 24 months, elotuzumab reduced the risk of cancer progression and death by 30%.

Patients in the elotuzumab group experienced a significantly longer period without disease progression (19.4 months, on average) than those in the control group (14.9 months, on average). 

In addition, two subgroups of patients with high-risk features ─ genetic abnormalities termed del(17p) and t[4;14] ─ appeared to benefit from elotuzumab as much as patients with average risk.

Conventional therapies tend to be less effective in those high-risk patients.

Overall, elotuzumab was well tolerated and did not deteriorate patient’s quality of life or exacerbate symptom burden.

Mild infusion reactions occurred after the first few doses in 10% of patients in the elotuzumab arm.

In 2014, the FDA granted a breakthrough therapy designation to elotuzumab in combination with lenalidomide and dexamethasone to treat patients with relapsed multiple myeloma.

This designation helps accelerate the development and review process for drugs to treat serious or life-threatening illnesses.

Ongoing clinical trials are exploring the possibility of incorporating elotuzumab into therapies for patients with newly diagnosed multiple myeloma and testing various combinations of elotuzumab and existing treatments.

Source: ASCO