Dose-intensified bendamustine followed by autologous peripheral blood stem cell support in relapsed and refractory multiple myeloma with impaired bone marrow function

Therapeutic options in heavily pretreated relapsed/refractory multiple myeloma patients are often very limited because of impaired bone marrow function. Bendamustine is effective in multiple myeloma and has a favourable toxicity profile. We hypothesized that dose-intensified bendamustine (180mg/m(2), day 1 and 2) followed by autologous blood stem cell support (ASCS) would improve bone marrow function with low post-transplant toxicity in patients with severely impaired haematopoiesis. We analyzed 28 consecutive myeloma patients, with a median of three prior lines of therapy (range 2-7), who had relapsed from the last treatment with very limited bone marrow function and were therefore ineligible for conventional chemotherapy, novel agents or trial enrolment. Dose-intensified bendamustine with ASCS improved haematopoiesis as reflected by increased platelet counts (median 40/nl vs 94/nl, p=0.0004) and white blood cell counts (3.0/nl vs 4.8/nl, p=0.02) at day +100. The median time until engraftment of platelets (>50/nl) was 11days (0-24days) and of white cell counts (>1.0/nl) 0days (0-24days). At least, a minimal response was achieved in 36% of patients. The disease stabilization rate was 50% while the median progression-free survival rate was limited to 2.14months. Most importantly, patients were once again eligible for alternative treatments including enrolment into clinical trials. We conclude that dose-intensified bendamustine followed by ASCS is safe and feasible for multiple myeloma patients with very limited bone marrow reserve. Copyright (c) 2015 John Wiley & Sons, Ltd.