Lenalidomide in combination with bendamustine and prednisolone in relapsed/refractory multiple myeloma: results of a phase 2 clinical trial (OSHO-#077).

INTRODUCTION: While lenalidomide monotherapy is established for relapsed and/or refractory multiple myeloma (MM) treatment, combination therapies including lenalidomide are still under investigation in a number of phase 2/3 studies. In the current study, a treatment regime of lenalidomide (Revlimid®), bendamustine and prednisolone (RBP) was tested in patients with relapsed/refractory MM. METHODS: In the previously completed phase 1 study RBP with a dose of 75 mg/m2 bendamustine days 1-2, prednisolone 100 mg days 1-4 and 25 mg lenalidomide days 1-21 was well tolerated. RESULTS: Between July 2011 and September 2013, 25 patients were included in this analysis. The median number of previous treatments was 1 (range 1-2). Twenty-two patients (88%) responded after at least two cycles of RBP (one sCR, five nCR, eight VGPR and eight PR). The median time to first haematological response was 28 days, and median time to best response was 56 days. Due to increased haematological toxicity a dose reduction in most patients required in subsequent cycles of therapy. The median progression-free and overall survival was 22 and 38 months, respectively. In conclusion RBP is a highly effective therapy for patients with relapsed/refractory MM. In contrast to our phase 1 study, dose reduction was necessary in many patients because of haematological toxicity.

Lenalidomide, bendamustine and prednisolone exhibits a favourable safety and efficacy profile in relapsed or refractory multiple myeloma: final results of a phase 1 clinical trial OSHO - #077.

This phase 1 dose finding study tested a combination of lenalidomide, bendamustine and prednisolone (RBP) in 21 patients in five cohorts with advanced multiple relasped/refractory myeloma (MM) to determine the maximum tolerable dose (MTD) of the combination. The first cohort received a starting dose of lenalidomide 10 mg/d, days 1-21, bendamustine 60 mg/m(2) /d, days 1-2, and prednisolone 100 mg/d, days 1-4. Dose escalation was done in cohorts of three to six patients with lenalidomide dose increasing to 15, 20 and 25 mg, and after reaching 25 mg/d, bendamustine was increased to 75 mg/m(2) . A total of 21 patients were enrolled and all completed at least two cycles. Two patients developed dose-limiting haemotoxicity: one patient on lenalidomide 25 mg/d and bendamustine 60 mg/m(2) and another patient at the highest dose level (lenalidomide 25 mg/d and bendamustine 75 mg/m(2) ). The MTD was not reached. Sixteen patients (76%) responded after at least two cycles of RBP with one stringent complete response (CR), one near CR, five very good partial response and nine partial response. After a median observation time of 16 months, progression-free survival at 18 months was 48% and overall survival was 64%. In conclusion, RBP with lenalidomide 25 mg/d, days 1-21 and bendamustine 75 mg/m(2) days 1-2 is well tolerated in patients with relapsed/refractory MM.