Updated analysis of CALGB 100104 (Alliance): a randomised phase III study evaluating lenalidomide vs placebo maintenance after single autologous stem cell transplant for multiple myeloma

BACKGROUND: CALGB 100104 (Alliance) studied lenalidomide vs. placebo following autologous stem cell transplant (ASCT) for newly diagnosed myeloma patients, demonstrating improved time to progression (TTP) and overall survival (OS), and an increase in second primary malignancies (SPM) for lenalidomide at 34-months median follow-up. Here we report an updated intent-to-treat analysis at 91-months median follow-up. METHODS: Patients were eligible if they had active myeloma, had received at most two induction regimens and had achieved stable disease or better in the first 100 days after ASCT. In this phase 3 study, 460 patients were randomised in a double-blind manner to either lenalidomide (n=231) or placebo (n=229) utilizing a permutated-block randomisation with fixed block size. Randomisation was stratified by three factors: normal or elevated β2-microglobulin level at registration (≤2·5 mg/L vs > 2·5 mg/L), prior use or nonuse of thalidomide during induction therapy, and prior use or nonuse of lenalidomide during induction therapy. The starting dose was 10 mg daily, escalated to 15 mg daily after three months. The primary endpoint was TTP (time of progressive disease or death from any cause) using intent-to-treat analysis. After three interim analyses, the study was unblinded at median follow-up of 18 months and 86/128 placebo patients without progressive disease chose to cross over to lenalidomide. This study is registered with ClinicalTrials.gov identifier NCT00114101; new patients are no longer being recruited, but some patients remain on treatment and in follow-up. FINDINGS: The median TTP for lenalidomide is 57·3 months (95% CI 44·2–73·3) and 28·9 months (95% CI 23·0–36·3) for placebo (hazard ratio (HR): 0·57, 95% CI 0·46–0·71, p<0·0001). The TTP benefit with lenalidomide was observed regardless of whether patients were in a complete response at time of randomisation or whether they had received thalidomide or lenalidomide induction therapy. The most common grade 3–4 adverse events were neutropenia (116 (50%) of 231 patients in the lenalidomide arm and 37 (16%) of 229 patients in the placebo arm) and thrombocytopenia (34 patients (15%) in the lenalidomide arm and 11 patients (4·8%) in the placebo arm. Eighteen haematological (7·8%) and 14 solid tumour (6·1%) SPMs have been diagnosed following randomisation and prior to disease progression in the lenalidomide arm vs. three haematological (1·3%) and nine solid tumour (3·9%) SPMs in the placebo arm. Of the placebo SPMs, three haematological and five of nine solid tumour SPMs were in the crossover subgroup. INTERPRETATION: Despite an increase in haematological adverse events and SPMs, lenalidomide maintenance therapy following ASCT significantly improves TTP and can be considered a standard of care.