Purpose This analysis of the FIRST trial in patients with newly diagnosed multiple myeloma (MM) ineligible for stem-cell transplantation examined updated outcomes and impact of patient age. Patients and Methods Patients with untreated symptomatic MM were randomly assigned at a one-to-one-to-one ratio to lenalidomide plus low-dose dexamethasone until disease progression (Rd continuous), Rd for 72 weeks (18 cycles; Rd18), or melphalan, prednisone, and thalidomide (MPT; 72 weeks), stratified by age (≤ 75 v > 75 years), disease stage (International Staging System stage I/II v III), and country. The primary end point was progression-free survival. Rd continuous and MPT were primary comparators. Results Between August 21, 2008, and March 7, 2011, 1,623 patients were enrolled (Rd continuous, n = 535; Rd18, n = 541; MPT, n = 547), including 567 (35%) age older than 75 years. Higher rates of advanced-stage disease and renal impairment were observed in patients older than 75 versus 75 years of age or younger. Rd continuous reduced the risk of progression or death compared with MPT by 31% (hazard ratio HR, 0.69; 95% CI, 0.59 to 0.80; P < .001) overall, 36% (HR, 0.64; 95% CI, 0.53 to 0.77; P < .001) in patients age 75 years or younger, and 20% (HR, 0.80; 95% CI, 0.62 to 1.03; P = .084) in those age older than 75 years. Median overall survival was longer with Rd continuous than with MPT, including a 14-month difference in patients age older than 75 years. Progression-free survival with Rd18 was similar to that with MPT, and overall survival with Rd18 was marginally inferior to that with Rd continuous. Rates of grade 3 to 4 treatment-emergent adverse events were similar for Rd continuous-treated patients age 75 years or older and those age older than 75 years; however, older patients had more frequent lenalidomide dose reductions. Conclusion Results support Rd continuous treatment as a new standard of care for stem-cell transplantation-ineligible patients with newly diagnosed MM of all ages.