A multicenter clinical study to determine the feasible initial dose of lenalidomide for maintenance therapy in patients with multiple myeloma following autologous peripheral blood stem‑cell transplantation

Maintenance therapy with lenalidomide (LEN) for patients with multiple myeloma (MM) following autologous peripheral blood stem cell transplantation (auto-PBSCT) may be a promising option for preventing relapse or disease progression. However, the recommended dose of LEN has yet to be firmly established. We herein report the results of a multicenter clinical study for determining the feasible initial dose (FID) of LEN. In this trial, a total of 11 patients who achieved a very good partial response or complete response following auto-PBSCT were enrolled from five transplant centers in Japan. Three dose levels of LEN (level 0, 5 mg; level 1, 10 mg; and level 2,:15 mg) were tested in this study. FID was defined as the maximum estimated dose at which 70% of the patients could receive maintenance therapy for 12 weeks without any serious adverse events or disease progression. Using a continual reassessment method, 6 patients were assigned to level 0 and the remaining 5 patients were assigned to level 1. All 6 patients (100%) at level 0, but only 2 patients (40%) at level 1, completed 12 weeks of administration with their assigned dose of LEN. The results of our study demonstrated that, although 5 mg of LEN was acceptable in terms of safety, 7.5 mg of LEN may also be an acceptable FID.