[Therapeutic effectiveness of vitamin D3 in patients with myelodysplastic syndromes, leukemias and myeloproliferative disorders].

We tried to treat 13 patients with myelodysplastic syndromes (MDS), leukemias and myeloproliferative disorders, with alfacalcidol for their hematological improvement. Eight of them had MDS, 2 acute leukemia (M3, M4), 1 chronic myelogenous leukemia and 2 primary myelofibrosis. All patients were untreated except for 3 patients (PASA, RAEB, AML-M4) who had been treated with mepitiostane, prednisolone and BH.AC-AMP regimen, respectively, prior to alfacalcidol therapy. All patients received alfacalcidol orally for at least one month. The dosage of alfacalcidol ranged from 0.25 to 10 micrograms/day, and the medicine was administrated intermittently when the dosage exceeded 6 micrograms/day to prevent hypercalcemia. The therapeutic effectiveness of alfacalcidol was evaluated according to a criteria by Koeffler (Cancer Treat Rep 69: 1399, 1985) with minor modifications. Three patients (PASA, RAEB, CMML) showed partial response, 3 (RAEB, RAEB in T, AML-M4) minor response and rest of the patients did not respond. The hematological improvement of 6 responders was transient (from 1 to 2 months), however, one patient (PASA) is still responding to alfacalcidol therapy (0.25 microgram/day) for over 12 months. The dysplastic features of hemopoietic cells in the bone marrow showed no noticeable change during the hematological improvement in these responders, suggesting the improvement was obtained as a result of alteration in the proliferation or differentiation of neoplastic clone. None of 13 patients developed hypercalcemia. One patient (AML-M4) became excitable on high dose alfacalcidol (10 micrograms/day). In conclusion, alfacalcidol therapy is effective in some patients with MDS or leukemias and appears worthy especially in the clinical state in which chemotherapy is not indicated.