[New aspects in the clinical course determination and therapy in multiple myeloma].

Multiple myeloma can be regarded as model disease for quantification of tumor mass, investigation of tumor cell kinetics and of tumor response to therapy. The quantification of the tumor cell number allows evaluation of prognosis and monitoring of disease as well as of therapy induced responses. Treatment of multiple myeloma is primarily based on the alkylating drugs cyclophosphamide and melphalan. In recent years other cytostatic substances, also effective in the treatment of this disorder have been introduced. However, the sensitivity determination of the individual myeloma stem cells seems to be the only possible method which possibly increases the response rate significantly. In accordance with these considerations we have, in preliminary clinical investigations, observed a good correlation between the in vitro determined cytostatic drug sensitivity and the in vivo response to therapy. Further progress in the treatment of multiple myeloma is to be expected with the introduction of interferon into the therapeutic regimen. Administration of this glycoprotein has resulted in significant reduction of tumor mass in more than half of all patients treated up to this time.