SAN DIEGO – For patients 65 years or younger with mantle cell lymphoma (MCL) who have undergone autologous stem cell transplantation (ASCT), maintenance therapy with lenalidomide (Revlimid) can significantly improve progression-free survival (PFS), suggest results of the phase, 3 randomized MCL0208 trial.
After a median follow-up of 39 months, the 3-year PFS in an intention-to-treat analysis was 80% for patients treated with ASCT and lenalidomide maintenance, compared with 64% for patients treated with ASCT alone, reported Marco Ladetto, MD, of Azienda Ospedaliera Nazionale SS. Antonio e Biagio e Cesare Arrigo in Alessandria, Italy.
“Lenalidomide maintenance after autologous stem cell transplant has substantial clinical activity in mantle cell lymphoma in terms of progression-free survival,” he said at the annual meeting of the American Society of Hematology. “Follow-up is still too short for meaningful overall survival considerations.”
Dr. Ladetto and his colleagues at centers in Italy and Portugalpatients aged 18-65 years with previously untreated MCL stage III or IV, or stage II with bulky disease (5 cm or greater), and good performance status.
The patients first underwent induction with three cycles of R-CHOP (rituximab, cyclophosphamide, doxorubicin, and prednisone), which was followed by treatment with rituximab plus high-dose cyclophosphamide and two cycles of rituximab with high-dose cytarabine. Stem cells were collected after the first course of the latter regimen.
The patients then underwent conditioning with BEAM (carmustine, etoposide, cytarabine, melphalan) and ASCT.
Following ASCT, patients with complete or partial remissions were randomized either to maintenance therapy with lenalidomide 15 mg for 21 of 28 days for each cycle or to observation.
Of the 303 patients initially enrolled, 248 went on to ASCT, and 205 went on to randomization – 104 assigned to maintenance and 101 assigned to observation.
A total of 52 patients completed 2 years of maintenance: Of the rest, 2 patients died from toxicities (thrombotic thrombocytopenic purpura and pneumonia), 7 had disease progression, 41 dropped out for nonprogression reasons, and 2 patients were still in maintenance at the time of the data cutoff. In this arm, 6 of 8 patients with partial responses converted to complete responses by the end of maintenance. More than a quarter of patients (28%) received less than 25% of the planned lenalidomide dose.
In the observation arm, 1 patient died from pneumonia, 20 had disease progression, 3 were lost to follow-up, 6 were still under observation, and 71 completed observation. In this arm, 1 of 4 patients with a partial response converted to a complete response at the end of the observation period.
Despite suboptimal dosing in a large proportion of patients, the PFS primary endpoint showed significant benefit for lenalidomide, with an unstratified hazard ratio of 0.52 (P = .015) and a stratified HR of 0.51 (P = .013).
At a median follow-up of 39 months from randomization, 3-year overall survival (OS) rates were 93% with lenalidomide and 86% with observation, a difference that was not statistically significant.
Grade 3 or 4 hematologic toxicities occurred in 63% of patients in the lenalidomide arm, compared with 11% in the observation arm. The respective rates of granulocytopenia were 59% vs. 10%. Nonhematological grade 3 toxicity was comparable in the two arms except for grade 3 or 4 infections, which were more common with lenalidomide. Seven patients in the lenalidomide arm and three patients in the observation arm developed second cancers.
Dr. Ladetto noted that difficulties in delivering the planned dose of lenalidomide may have been caused by an already-stressed hematopoietic compartment; he commented that the question of the relative benefit of a fixed lenalidomide schedule or an until-progression approach still needs to be answered.
Additionally, the induction schedule used in the trial, while feasible, is not superior to “less cumbersome and possibly less toxic regimens,” he said.
The study was supported by the Italian Lymphoma Foundation (Fondazione Italiana Linfomi) with the European Mantle Cell Lymphoma Network. Dr. Ladetto reported honoraria from Roche, Celgene, Acerta, Janssen, AbbVie, and Sandoz, as well as off-label use of lenalidomide.
SOURCE: Ladetto M et al. ASH 2018, Abstract 401.