Carfilzomib-lenalidomide-dexamethasone versus lenalidomide-dexamethasone in patients with newly diagnosed myeloma ineligible for autologous stem-cell transplantation (EMN20): a randomised, open-label, multicentre, phase 3 trial.

Background: Before the introduction of daratumumab-lenalidomide-dexamethasone as a first-line treatment for patients with newly diagnosed transplant-ineligible multiple myeloma, lenalidomide-dexamethasone was a standard of care. We aimed to explore whether addition of the second-generation proteasome inhibitor carfilzomib to lenalidomide-dexamethasone improved the rates of measurable residual disease (MRD) negativity and progression-free survival.

Methods: EMN20 is a randomised, open-label, multicentre, phase 3 trial comparing weekly carfilzomib-lenalidomide-dexamethasone versus lenalidomide-dexamethasone in patients with newly diagnosed transplant-ineligible multiple myeloma, conducted in 27 centres in Italy. Key inclusion criteria included fit or intermediate-fit status according to the International Myeloma Working Group (IMWG) frailty score, measurable disease according to IMWG criteria, and Eastern Cooperative Oncology Group performance status lower than 3. Patients randomly assigned to the carfilzomib-lenalidomide-dexamethasone group received 28-day carfilzomib-lenalidomide-dexamethasone cycles (carfilzomib 20 mg/m intravenously on day 1 for cycle 1, followed by 56 mg/m intravenously on days 8 and 15 for cycle 1, then 56 mg/m intravenously on days 1, 8, and 15 for cycles 2-12, and 56 mg/m intravenously on days 1 and 15 from cycle 13 until 5 years after randomisation; lenalidomide 25 mg orally on days 1-21 until disease progression or intolerance; dexamethasone 40 mg orally on days 1, 8, 15, and 22 until disease progression or intolerance). Patients assigned to the lenalidomide-dexamethasone group received 28-day cycles with lenalidomide-dexamethasone (same dosing and schedule used in the carfilzomib-lenalidomide-dexamethasone group). Primary endpoints were MRD negativity by next-generation sequencing (sensitivity 10) after 2 years of treatment and progression-free survival; and were assessed in the intention-to-treat (ITT) population (all patients who were eligible to receive treatment and who were randomly assigned to one of the treatment groups). On Nov 23, 2021, after enrolling 30% of planned patients (101/340), the trial was prematurely stopped due to the introduction of daratumumab-lenalidomide-dexamethasone as a first-line treatment in Italy, which caused the lenalidomide-dexamethasone control group to no longer be considered a standard treatment. This trial is registered with ClinicalTrials.gov, NCT04096066, and study recruitment is complete.

Findings: Between Nov 14, 2019, and Nov 23, 2021, 82 of 101 enrolled patients were assessed for eligibility and were randomised to receive carfilzomib-lenalidomide-dexamethasone (n=42) or lenalidomide-dexamethasone (n=40). In the ITT population, 35 (43%) of 82 patients were female and 47 (57%) were male. At data cutoff (March 29, 2024), the median follow-up was 35·2 months (IQR 30·3-38·7). The 2-year MRD negativity rates were 25 (60% 95% CI 43-74) of 42 patients with carfilzomib-lenalidomide-dexamethasone versus 0 (0%; 0-9) of 40 patients with lenalidomide-dexamethasone (p<0·0001). Median progression-free survival was not reached (not reached-not reached) with carfilzomib-lenalidomide-dexamethasone versus 20·9 months (15·7-not reached) with lenalidomide-dexamethasone (hazard ratio 0·24 [95% CI 0·11-0·56], p=0·00084). One patient was excluded from the safety analysis because they died before starting treatment. The most frequent grade 3 or worse adverse events were neutropenia (nine [22%] of 41 patients), thrombocytopenia (four [10%]), diarrhoea (four [10%]), cardiac events (three [7%]), infections (three [7%]), and arterial hypertension (two [5%]) with carfilzomib-lenalidomide-dexamethasone, and neutropenia (six [15%] of 40) and skin rash (four [10%]) with lenalidomide-dexamethasone. The most common serious adverse event was SARS-CoV-2-related pneumonia in both the carfilzomib-lenalidomide-dexamethasone group (two [5%] of 41 patients) and lenalidomide-dexamethasone group (three [7%] of 40 patients). Treatment-emergent adverse events leading to death were observed in two patients in the carfilzomib-lenalidomide-dexamethasone (two SARS-CoV-2 infections) and four patients in the lenalidomide-dexamethasone group (one acute myocardial infraction, one heart failure, one septic shock, and one SARS-CoV-2 infection).

Interpretation: With the limitation of a smaller sample size than planned due to the trial's early interruption, these results, to our knowledge, showed for the first-time high rates of MRD negativity with weekly carfilzomib added to lenalidomide-dexamethasone in patients with transplantation-ineligible newly diagnosed multiple myeloma. In the carfilzomib-lenalidomide-dexamethasone group, higher MRD negativity rates were associated with a progression-free survival advantage over lenalidomide-dexamethasone. Toxicities were predictable and generally manageable.

Funding: Amgen, Bristol Myers Squibb.