Bortezomib and melphalan as a conditioning regimen for autologous stem cell transplantation in multiple myeloma

High-dose melphalan (200 mg/m(2)) with autologous stem cell transplantation (ASCT) is the standard treatment for young patients with multiple myeloma (MM). However, the response rates after ASCT are often unsatisfactory. We performed a pilot study by using bortezomib-melphalan as conditioning regimen for ASCT in Korean patients with MM.

The conditioning regimen consisted of administration of intravenous infusion of bortezomib 1.0 mg/m(2) on days -4 and -1 and melphalan 50 mg/m(2) (day -4) and 150 mg/m(2) (day -1). In this study, we enrolled 6 newly diagnosed patients and 2 patients with relapse.

The disease status of the 6 newly diagnosed patients at ASCT was as follows: 1 complete remission (CR), 1 very good partial remission (VGPR), and 4 partial remissions (PRs). The disease status of the 2 relapsed patients at ASCT was PR. All patients except 1 showed adequate hematologic recovery after ASCT. The median time for the absolute neutrophil counts to increase over 500/mm(3) was 13 days (range, 10-19 days). Six patients with VGPR or PR at the time of transplantation showed an improvement in response to CR after ASCT. The patients were followed up without any maintenance treatment after ASCT except 1 patient who died during ASCT. During the follow-up period, CR was maintained in 3 newly diagnosed patients, but the other 4 patients, including 2 newly diagnosed patients, relapsed.

Conditioning regimen consisting of bortezomib and melphalan may be effective for ASCT in MM; however, the feasibility of this regimen should be further evaluated in large study populations.