Phase II trial of mitoxantrone in multiple myeloma: A southwest oncology group study

Thirty-five fully evaluable patients with advanced multiple myeloma, refractory to standard chemotherapeutic agents, were entered into a phase II trial with mitoxantrone at a starting dose of 12 mg/m² iv every 3 weeks. There was one (3%) partial response (lasting 2 1/2 months) in a patient who had received treatment with five different agents, including doxorubicin (total dose, 150 mg/m²). Four additional patients (11%) showed objective evidence of clinical improvement, lasting 4-7 months. Mitoxantrone was well-tolerated with no drug-induced deaths and only moderate to severe leukopenia as the dose-limiting toxicity in the majority of patients. Although mitoxantrone had a low level of activity in this heavily pretreated patient population, consideration should be given to future trials incorporating mitoxantrone into a new drug combination.