n the EMN01 trial, the addition of an
alkylator (
melphalan or
cyclophosphamide) to
lenalidomide-
steroid induction
therapy was prospectively evaluated in transplant-ineligible patients with
multiple myeloma. After induction, patients were randomly assigned to maintenance treatment with
lenalidomide alone or with
prednisone continuously. The analysis presented here (median follow-up of 71 months) is focused on maintenance treatment and on subgroup analyses defined according to the International Myeloma Working Group
Frailty Score. Of the 654 evaluable patients, 217 were in the
lenalidomide-
dexamethasone arm, 217 in the
melphalan-
prednisone-
lenalidomide arm and 220 in the
cyclophosphamide-
prednisone-
lenalidomide arm. With regards to the
Frailty Score, 284 (43%) patients were fit, 205 (31%) were intermediate-fit and 165 (25%) were frail. After induction, 402 patients were eligible for maintenance
therapy (
lenalidomide arm, n=204;
lenalidomide-
prednisone arm, n=198). After a median duration of maintenance of 22.0 months, progression-free survival from the start of maintenance was 22.2 months with
lenalidomide-
prednisone vs 18.6 months with
lenalidomide (hazard ratio 0.85, P=0.14), with no differences across
frailty subgroups. The most frequent grade ≥3 toxicity was
neutropenia (10% of
lenalidomide-
prednisone and 21% of
lenalidomide patients; P=0.001). Grade ≥3 non-hematologic adverse events were rare (<15%). In fit patients,
melphalan-
prednisone-
lenalidomide significantly prolonged progression-free survival compared to
cyclophosphamide-
prednisone-
lenalidomide (hazard ratio 0.72, P=0.05) and
lenalidomide-
dexamethasone (hazard ratio 0.72, P=0.04). Likewise, a trend towards a better overall survival was noted for patients treated with
melphalan-
prednisone-
lenalidomide or
cyclophosphamide-
prednisone-
lenalidomide, as compared to
lenalidomide-
dexamethasone. No differences were observed in intermediate-fit and frail patients. This analysis showed positive outcomes of maintenance with
lenalidomide-based regimens, with a good safety profile. For the first time, we showed that fit patients benefit from a full-dose triplet regimen, while intermediate-fit and frail patients benefit from gentler regimens. ClinicalTrials.gov registration number: NCT01093196.