engleski

MULTIDRUG RESISTANCE IN MULTIPLE MYELOMA. IS THERE A PLACE FOR IDARUBICIN IN CHEMOTHERAPY?

Background: Poor response to chemotherapy in multiple myeloma (MM) has been associated with the development of multidrug resistance (MDR) primarily following the increase of P-glycoprotein (Pgp) expression. Therefore, the need for the new chemotherapy protocols with MDR-independent substrates has emerged. Study: Pgp phenotype and function of bone marrow cells during the follow-up of 78 consecutive MM patients, differing in the clinical stage and disease duration, had been analysed. The patients were treated according to the standard MM chemotherapy protocols, also including a small group of patients treated with VID (modified VAD) protocol (vincristine, idarubicin, dexamethasone), MDR-independent idarubicin replacing the MDR-dependent adriamycin (1). Results: Pgp expression on plasma cells increased with clinical stage of disease: the highest in clinical stage III (p<0.046). On the same cell population, the MDR-dependent treatment increased Pgp expression (p<0.003). The plasma cell population expressing Pgp increased with the lack of response to treatment (CR vs. NR p<0.023), and with the fatal outcome (p<0.001), associating the size of the plasma cell population to the seriousness of the patients condition. Despite their high Pgp expression, the patients on VID protocol had significantly (p<0.005) smaller plasma cell population, further decreasing with the duration of the VID therapy (p<0.001). Conclusion: Our preliminary results indicate that by using idarubicin to circumvent MDR, the modified VID protocol might enhance chemotherapeutic efficacy in the treatment of MM. 1. Leukemia Research 1999 ; 23: 539-548.

MDR; Multiple myeloma; Idarubicin

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