Post-transplant consolidation therapy using thalidomide alone for the patients with multiple myeloma: A feasibility study in Japanese population

In order to test for improved survival following autologous transplantation (ASCT), we conducted a prospective clinical trial of post-ASCT thalidomide therapy in Japanese patients with multiple myeloma (MM). Twentyfive newly diagnosed patients received double or single ASCT with high-dose melphalan (200 mg/m²). Two months after stem cell infusion, if the patients failed to achieve a near-complete response, thalidomide was administered at 200 mg/day until disease progression or occurrence of intolerable adverse events. Seventeen patients were in partial response or minimal response after ASCT and received thalidomide alone. Their median progression- free survival (PFS) from ASCT was 17.4 months, and the median overall survival (OS) was 42.9 months. Some patients with normal karyotype experienced durable disease stabilization for over 5 years. Five patients who exhibited high-risk chromosomal changes such as t(4;14) or deletion of chromosome 13 or 17 showed very short PFS and OS compared with those who did not. Observed grade 3 or 4 toxicities included infection in three patients, hematological toxicities in three, and gastrointestinal toxicities in two, but there was no grade 3 or higher peripheral neuropathy, probably due to appropriate dose modifications. This long-term prospective study is the first to demonstrate the feasibility of post-ASCT thalidomide therapy in Japanese patients with MM.