Induction therapy with lenalidomide and dexamethasone increased time to progression and improved survival in patients with smoldering multiple myeloma, according to results of a randomized phase 3 trial.
Observation, which is the standard of care for patients with smoldering multiple myeloma, may not be effective for identifying high-risk patients who are candidates for early intervention, according to researchers.
The current open-label trial included 119 individuals with high-risk smoldering disease.
Patients in the treatment arm were assigned nine cycles of an induction regimen of lenalidomide (Revlimid, Celgene) at 25 mg per day on days 1 to 21, plus dexamethasone at 20 mg/day on days 1 to 4 and days 12 to 15 at 4-week intervals. This regimen was followed by maintenance lenalidomide therapy at 10 mg/day on days 1 to 21 of each 28-day cycle for 2 years.
Patients in the other arm underwent observation.
Progression to symptomatic disease served as the primary endpoint. Secondary outcome measures included response rate, OS and safety.
Median follow-up was 40 months.
Researchers reported a significantly longer median time to progression in the treatment arm compared with the observation arm (not reached vs. 21 months; HR for progression=0.18; 95% CI, 0.09-0.32).
The 3-year survival rate was 94% in the treatment group and 80% in the observation group (HR for death=0.31; 95% CI, 0.10-0.91), which the researchers noted was also a significant difference.
Seventy-nine percent of patients in the treatment group achieved a partial response or better after induction, and 90% achieved this response during maintenance.
Safety profile results indicated that most toxicities were grade 2 or lower.