For patients with smoldering multiple myeloma, the standard of care is observation until symptoms develop. However, this approach does not identify high-risk patients who may benefit from early intervention.
In a randomized, open-label, phase 3 trial, researchers have randomly assigned 119 patients with high-risk smoldering myeloma to treatment or observation.
Patients in the treatment group received an induction regimen ( Lenalidomide [ Revlimid ] at a dose of 25 mg per day on days 1 to 21, plus Dexamethasone at a dose of 20 mg per day on days 1 to 4 and days 12 to 15, at 4-week intervals for nine cycles ), followed by a maintenance regimen ( Lenalidomide at a dose of 10 mg per day on days 1 to 21 of each 28-day cycle for 2 years ).
The primary end point was time to progression to symptomatic disease. Secondary end points were response rate, overall survival, and safety.
After a median follow-up of 40 months, the median time to progression was significantly longer in the treatment group than in the observation group ( median not reached vs 21 months; hazard ratio for progression, HR=0.18; P less than 0.001 ).
The 3-year survival rate was also higher in the treatment group ( 94% vs 80%; hazard ratio for death, HR=0.31; P=0.03 ).
A partial response or better was achieved in 79% of patients in the treatment group after the induction phase and in 90% during the maintenance phase.
Toxic effects were mainly grade 2 or lower.
The study has shown that early treatment for patients with high-risk smoldering myeloma delays progression to active disease and increases overall survival. ( Xagena )
Mateos M-V et al, N Engl J Med 2013; 369:438-447