Background. Multiple myeloma is the second most prevalent and mostly fatal hematologic cancer. Further advances have been made in understanding the mechanisms involved in the myeloma pathogenesis and elucidation of critical signalling pathways as therapeutical targets. Proteasome inhibitors are the example of this new approach and bortezomib is the first agent in this class to enter clinical trials. Methods and Results. In 6 hematological centers in Czech Republic 29 patients with refractory/relapsed myeloma had been treated with bortezomib (Velcade, Millennium Pharmaceuticals) in 2004. The initial dose 1.3 mg/m2 of Velcade was given, in 1 case the dose was adjusted due to pre-existing renal failure to 1 mg/m2. The response was achieved in 17 patients (59%). Four patients had complete, 11 partial and two minor responses. In 5 cases stabilization of disease was observed and 6 patients progressed during the therapy. Conclusions. Unfortunately, one patient died immediately after the start of therapy due to sepsis. The most common adverse events were thrombocytopenia, anaemia, neuropathy, gastrointestinal complication, renal failure and fatigue. Grade 4 adverse events occurred in 37,9 % of patients (4x thrombocytopenia, 2x gastrointestinal, 2x renal failure, 1x sepsis, leucopenia, hepatopathy and anaemia, respectively). Peripheral neuropathic pain of grade 3 was reported in 4 cases, in one patient therapy had to be interrupted due to this complication. We confirmed promising results of phase II trials.

        Key words: multiple myeloma, proteasome, bortezomib, renal failure.