Common and rare side-effects of low-dose thalidomide in multiple myeloma: focus on the dose-minimizing peripheral neuropathy.

OBJECTIVES: Thalidomide has demonstrated a remarkable efficacy in the treatment of multiple myeloma but its use may cause several toxicities. We have investigated the common and rare side-effects, especially analysing peripheral neuropathy, in order to optimise the thalidomide dose for minimizing this harmful side-effect. METHODS: Fifty-nine patients were treated with thalidomide alone or combined with oral melphalan. The median age was 69 yr. The initial dose of thalidomide was 100 mg/day increasing weekly by 100 mg increments until a maximum dose of 400 mg was attained. Melphalan was administered at a dose of 0.20 mg/kg/d for 4 d every 28 d. RESULTS AND CONCLUSIONS: Nearly one-fourth of patients discontinued thalidomide because of toxicity. Constipation (71%), somnolence (36%) and fatigue (20%) were the most common side-effects and they were not dose dependent. Peripheral neuropathy occurred in 39% of patients and a thalidomide median daily dose of more than 150 mg was significantly associated with higher frequency and actuarial risk of peripheral neuropathy without improving the response rate. Deep venous thrombosis was observed in 7% of patients and other side-effects were rare. In patients with advanced multiple myeloma we found that a thalidomide daily dose of 150 mg minimizes peripheral neuropathy without jeopardizing response and survival.