Decitabine
Indications
Decitabine is indicated for treatment of adult patients with myelodysplastic syndromes (MDS) including previously treated and untreated, de novo and secondary MDS of all French-American-British subtypes (refractory anemia, refractory anemia with ringed sideroblasts, refractory anemia with excess blasts, refractory anemia with excess blasts in transformation, and chronic myelomonocytic leukemia) and intermediate-1, intermediate-2, and high-risk International Prognostic Scoring System groups.
Pharmacology
Decitabine is believed to exert its antineoplastic effects after phosphorylation and direct incorporation into DNA and inhibition of DNA methyltransferase, causing hypomethylation of DNA and cellular differentiation or apoptosis. Decitabine inhibits DNA methylation in vitro, which is achieved at concentrations that do not cause major suppression of DNA synthesis. Decitabine-induced hypomethylation in neoplastic cells may restore normal function to genes that are critical for the control of cellular differentiation and proliferation. In rapidly dividing cells, the cytotoxicity of decitabine may also be attributed to the formation of covalent adducts between DNA methyltransferase and decitabine incorporated into DNA. Non-proliferating cells are relatively insensitive to decitabine.
Dosage & Administration
Three Day Regimen: Administer DACOGEN at a dose of 15 mg/m2 by continuous intravenous infusion over 3 hours repeated every 8 hours for 3 days. Repeat cycles every 6 weeks upon hematologic recovery (ANC at least 1,000/µL and platelets at least 50,000/µL) for a minimum of 4 cycles. . A complete or partial response may take longer than 4 cycles. Delay and reduce dose for hematologic toxicity
Five Day Regimen: Administer DACOGEN at a dose of 20 mg/m2 by continuous intravenous infusion over 1 hour daily for 5 days. Delay and reduce dose for hematologic toxicity (see Dose Modifications for Toxicity). Repeat cycles every 4 weeks upon hematologic recovery (ANC at least 1,000/µL and platelets at least 50,000/µL) for a minimum of 4 cycles. A complete or partial response may take longer than 4 cycles.
Five Day Regimen: Administer DACOGEN at a dose of 20 mg/m2 by continuous intravenous infusion over 1 hour daily for 5 days. Delay and reduce dose for hematologic toxicity (see Dose Modifications for Toxicity). Repeat cycles every 4 weeks upon hematologic recovery (ANC at least 1,000/µL and platelets at least 50,000/µL) for a minimum of 4 cycles. A complete or partial response may take longer than 4 cycles.
Interaction
Drug interaction studies with decitabine have not been conducted. In vitro studies in human liver microsomes suggest that decitabine is unlikely to inhibit or induce cytochrome P450 enzymes. In vitro metabolism studies have suggested that decitabine is not a substrate for human liver cytochrome P450 enzymes. As plasma protein binding of decitabine is negligible (<1%), interactions due to displacement of more highly protein bound drugs from plasma proteins are not expected.
Side Effects
Most common adverse reactions (>50%) are neutropenia, thrombocytopenia, anemia, and pyrexia.
Pregnancy & Lactation
Based on findings from human data, animal studies, and the mechanism of action, Decitabine can cause fetal harm when administered to a pregnant woman. Advise not to breastfeed. There are no data on the presence of decitabine or its metabolites in human milk, the effects on the breastfed child, or the effects on milk production.
Precautions & Warnings
Neutropenia and thrombocytopenia: Perform complete blood counts and platelet counts.
Embryo-fetal Toxicity: Can cause fetal harm. Advise patients of reproductive potential of the potential risk to a fetus and to use effective contraception.
Embryo-fetal Toxicity: Can cause fetal harm. Advise patients of reproductive potential of the potential risk to a fetus and to use effective contraception.
Storage Conditions
Keep below 25°C temperature, away from light & moisture. Keep out of the reach of children.
