Vitamin D(2) analog (Paricalcitol; Zemplar) for treatment of myelodysplastic syndrome.
Author(s): Koeffler HP, Aslanian N, O'Kelly J
Affiliation(s): Division of Hematology/Oncology, Davis 5005, Cedars-Sinai Medical Center, UCLA School of Medicine, 8700 Beverly Blvd., Los Angeles, CA 90048, USA.
Publication date & source: 2005-11, Leuk Res., 29(11):1259-62. Epub 2005 Apr 26.
Publication type: Clinical Trial
Myelodysplastic syndrome (MDS) is often a pernicious disorder associated with pancytopenia in the elderly; therapeutic approaches need to balance their toxicities versus the symptoms of the disease. 1,25(OH)(2)-Vitamin-D(3) [1,25(OH)(2)D(3)] inhibits proliferation and induces differentiation of leukemic cells in vitro. Small clinical trials of 1,25(OH)(2)D(3) have shown modest efficacy in MDS; hypercalcemia prevented the administration of doses that have been shown to be effective in vitro. Paricalcitol [19-nor-1,25(OH)(2)D(2), Zemplar] has been approved by the FDA for treatment of secondary hyperparathyroidism. This Vitamin D analog is unique because it has little hypercalcemic potential; but in vitro, it has strong anti-leukemic activity. We conducted a clinical trial of oral paricalcitol to 12 MDS patients whose disease varied between an IPSS of low to high. Drug was well-tolerated in all patients. No responses were observed according to international working group (IWG) criteria. However, the platelet count of 1 of the 12 individuals rose from 53,500 to 120,000/microl blood over 5 weeks; but the patient succumbed to a fatal fungal infection. In summary, paricalcitol given as a single agent to MDS patients is therapeutically not very efficacious; further trials of the Vitamin D analog should be considered in combination with other approaches.