Introduction: There is a great need for alternative treatments for patients with relapsing and refractory multiple myeloma. The new anthracycline idarubicin has the advantage of oral administration and has been suggested as part of new orally based chemotherapeutic combination regimens. The evidence of its own efficacy in this disorder is, however, insufficient.
Materials and methods: In a multi-centre phase II study we administered oral idarubicin as a single drug in a dose of 10 mg/m(2) days 1-4 every four weeks to a total of 30 patients with relapsing (n=18) or refractory (n=12) multiple myeloma.
Results: Of 28 evaluable patients only one achieved a partial response of 15 months' duration. Other patients showed a very short minor response (n=1), "no change" (n=11) or progression (n=15) during the therapy. Toxicity was mostly mild and the drug was fairly well tolerated. None the less, half of the patients experienced WHO grade 3 and 4 toxicity in the form of granulocytopenia (n=10) or thrombocytopenia (n=4).
Conclusion: Based on our experience and available data from three previously published reports, we consider idarubicin to have only a marginal effect in relapsing and refractory myeloma. A review of the literature on studies of anthracylines as single-agent therapy shows that only 5% of patients (19 out of 377) show a partial response. In our opinion the regular inclusion of an anthracycline in drug combinations for refractory myeloma should be reconsidered.