Continuous lenalidomide-dexamethasone treatment is effective for patients not eligible for stem cell transplantation

This study examined the effectiveness of lenalidomide (Revlimid) and dexamethasone (Ozurdex) in treating patients with newly diagnosed multiple myeloma not eligible for a stem cell transplant. Authors reported superior treatment outcomes with continuous lenalidomide compared to 18 cycles of lenalidomide or standard-of-care.

High-dose chemotherapy followed by stem cell transplantation is a standard treatment for newly diagnosed multiple myeloma. However, a transplant is not tolerable or beneficial for all patients. MPT is commonly prescribed for patients not eligible to undergo stem cell transplantation. This is a combination of the chemotherapy drug melphalan (Alkeran), the steroid drug prednisone, and the biologic drug thalidomide (Immunoprin).

Lenalidomide is a recently developed type of biologic therapy that uses the patient's immune system to fight cancer. Lenalidomide combined with the steroid drug dexamethasone has been used effectively as a second-line option for previously treated multiple myeloma. Its benefit as a first-line and maintenance treatment (long-term therapy to prevent progression) is unclear.

The aim of this study was to examine lenalidomide-dexamethasone as a first-line treatment option for patients not eligible for stem cell transplantation.

1,623 patients with newly diagnosed multiple myeloma were included. Patients were randomly assigned to one of three treatment groups. 535 patients received lenalidomide plus dexamethasone continuously for an average of 18.4 months (until disease progression). 541 patients received 18 cycles (each lasting 28 days) of the same treatment combination for an average of 16.6 months. 547 patients received MPT for an average of 15.4 months.

The average time until disease progression was 25.5 months in the continuous lenalidomide-dexamethasone group. This was significantly longer compared to patients receiving 18 cycles of lenalidomide-dexamethasone (20.7 months) or MPT (21.2 months).

4-year overall survival rate (proportion who have not died from any cause since treatment) was 59% with continuous lenalidomide-dexamethasone. This was significantly higher compared to 18 cycles of lenalidomide-dexamethasone (56%) and MPT (51%). On average, the risk of death was reduced by 22% among patients treated with continuous lenalidomide-dexamethasone. This was unaffected by patient age. However, those with high-risk disease were less likely to show the same benefit.

Treatment response rates were also superior among patients treated with continuous lenalidomide-dexamethasone (75%). 73% of patients undergoing 18 cycles of lenalidomide-dexamethasone and 62% of patients treated with MPT showed the same response. 43% of patients received second-line therapy in the continuous lenalidomide-dexamethasone group. This was 55% in the group receiving 18 cycles of lenalidomide-dexamethasone and 56% in the MPT group.

Overall, the rate of at least one serious side effect occurring was similar across the 3 groups (80 to 89%). Continuous lenalidomide-dexamethasone was associated with fewer blood-related or neurological side effects as well as fewer secondary blood cancers. More cases of infection were observed with continuous lenalidomide-dexamethasone.

Authors concluded that continuous lenalidomide-dexamethasone improved disease progression and survival in patients with newly diagnosed multiple myeloma not eligible for stem cell transplantation.