Sequential Approach with Bortezomib as Induction Before Autologous Transplantation, Followed by Lenalidomide as Consolidation-Maintenance in Untreated Multiple Myeloma Patients.

Bortezomib induction before autologous stem cell transplantation (ASCT) has shown its efficacy in newly diagnosed multiple myeloma (MM) patients, both in association with dexamethasone alone (Harousseau JL, et al. Blood 110, 2007, abstr 450) and in combination with doxorubicin and dexamethasone (Popat R, et al. Br J Haematol 141:512-516, 2008). Lenalidomide, a less toxic and more potent thalidomide-derivative, lacks the neurotoxic effects of the parent drug and represents an optimal agent to include in maintenance regimens.

These observations provided the rationale for investigating a sequential approach including bortezomib as induction and lenalidomide as consolidation-maintenance in MM patients undergoing ASCT.

A hundred and two newly diagnosed patients aged 65–75 years were enrolled in 17 Italian centers. Induction (PAD) included four 21-day cycles of bortezomib (1.3 mg/m2 days 1,4,8,11), pegylated-liposomal-doxorubicin (30 mg/m2 day 4), and dexamethasone (40 mg/day: cycle 1, days 1–4, 8–11, 15–18; cycles 2–4, days 1–4). Autologous transplantation was tandem melphalan 100 mg/m² (MEL100) followed by stem-cell support. After ASCT, patients received consolidation with four 28-day cycles of lenalidomide (25 mg/day days 1–21 every 28 days) plus prednisone (50 mg every other day) (LP), followed by maintenance (L) with lenalidomide alone (10 mg/day days 1–21 every 28 days) until relapse. Primary endpoints were safety (incidence of grade 3–4 adverse events [AEs]) and efficacy (response rate). Secondary endpoints were progression-free survival (PFS) and overall survival (OS). Time-to-event estimates analysis was performed using the Kaplan-Meier method.

Very good partial response (VGPR) or better was 58% after PAD induction and increased to 82% after MEL100 and to 86% during LP-L. Complete response (CR) rate was 13% after PAD induction, increased to 38% after MEL100 and to 66% during LP-L. After a median follow-up of 2 years, the 2-year PFS was 69%, the 2-year time-to-progression was 75% and the 2-year OS was 86%. During PAD induction, main grade 3–4 AEs were thrombocytopenia (17%), neutropenia (10%), peripheral neuropathy (16%), and pneumonia (10%); treatment-related mortality was 3%. During consolidation-maintenance grade 3–4 AEs included neutropenia (16%), thrombocytopenia (6%), pneumonia (5%), and cutaneous rash (4%). Consolidation-maintenance treatment was well tolerated: only 4% of patients required Granulocyte-colony stimulating factor support and no patient required platelet transfusion; dermatological toxicity was easily manageable with dose-reduction and supportive therapy; no treatment-related deaths were reported. Updated results will be presented at the meeting.

This is the first phase II study in newly diagnosed MM patients to date, where a sequential approach including bortezomib as induction, and lenalidomide as post ASCT consolidation-maintenance was explored. Treatment was correlated with an increase in response rate and in the depth of response (CR rate) and was generally well tolerated. These data suggest that this is a safe and effective regimen for newly diagnosed MM patients. Randomized trials are needed to confirm these results.

Patriarca:Celgene: Honoraria; Janssen Cilag: Honoraria. Bringhen:Celgene: Honoraria; Janssen Cilag: Honoraria. Boccadoro:Janssen Cilag : Consultant, advisory committee, Research Funding; Celgene: Consultant, advisory committee, Research Funding; Pharmion: Consultant, advisory committee, Research Funding. Palumbo:Celgene: Honoraria; Janssen Cilag: Honoraria.