The following adverse reactions have been identified during postapproval use of decitabine. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure.
- Sweet’s syndrome (acute febrile neutrophilic dermatosis)
- Differentiation syndrome
- Interstitial lung disease
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.
Based on findings from human data, animal studies, and the mechanism of action, decitabine can cause fetal harm when administered to a pregnant woman [ see Clinical Pharmacology (12.1) and Nonclinical Toxicology (13.1)]. Limited published data on decitabine use throughout the first trimester during pregnancy describe adverse developmental outcomes including major birth defects (structural abnormalities). In animal reproduction studies, administration of decitabine to pregnant mice and rats during organogenesis caused adverse developmental outcomes including malformations and embryo-fetal lethality starting at doses approximately 7% of the recommended human dose on a mg/m2 basis (see Data). Advise pregnant women of the potential risk to a fetus.
The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. The estimated background risk of major birth defects and miscarriage in the U.S. general population is 2% to 4% and 15% to 20% of clinically recognized pregnancies, respectively.
A single published case report of decitabine pregnancy exposure in a 39-year old woman with a hematologic malignancy described multiple structural abnormalities after 6 cycles of therapy in the 18th week of gestation. These abnormalities included holoprosencephaly, absence of nasal bone, mid-facial deformity, cleft lip and palate, polydactyly and rocker-bottom feet. The pregnancy was terminated.
In utero exposure to decitabine causes temporal related defects in the rat and/or mouse, which include growth suppression, exencephaly, defective skull bones, rib/sternabrae defects, phocomelia, digit defects, micrognathia, gastroschisis, micromelia. Decitabine inhibits proliferation and increases apoptosis of neural progenitor cells of the fetal CNS and induces palatal clefting in the developing murine fetus. Studies in mice have also shown that decitabine administration during osteoblastogenesis (day 10 of gestation) induces bone loss in offspring.
In mice exposed to single IP (intraperitoneal) injections (0, 0.9 and 3.0 mg/m2 , approximately 2% and 7% of the recommended daily clinical dose, respectively) over gestation days 8, 9, 10 or 11, no maternal toxicity was observed but reduced fetal survival was observed after treatment at 3 mg/m2 and decreased fetal weight was observed at both dose levels. The 3 mg/m2 dose elicited characteristic fetal defects for each treatment day, including supernumerary ribs (both dose levels), fused vertebrae and ribs, cleft palate, vertebral defects, hind-limb defects and digital defects of fore- and hind-limbs.
In rats given a single IP injection of 2.4, 3.6 or 6 mg/m2 (approximately 5%, 8%, or 13% the daily recommended clinical dose, respectively) on gestation days 9-12, no maternal toxicity was observed. No live fetuses were seen at any dose when decitabine was injected on gestation day 9. A significant decrease in fetal survival and reduced fetal weight at doses greater than 3.6 mg/m2 was seen when decitabine was given on gestation day 10. Increased incidences of vertebral and rib anomalies were seen at all dose levels, and induction of exophthalmia, exencephaly, and cleft palate were observed at 6.0 mg/m2. Increased incidence of foredigit defects was seen in fetuses at doses greater than 3.6 mg/m2. Reduced size and ossification of long bones of the fore-limb and hind-limb were noted at 6.0 mg/m2.
The effect of decitabine on postnatal development and reproductive capacity was evaluated in mice administered a single 3 mg/m2 IP injection (approximately 7% the recommended daily clinical dose) on day 10 of gestation. Body weights of males and females exposed in utero to decitabine were significantly reduced relative to controls at all postnatal time points. No consistent effect on fertility was seen when female mice exposed in utero were mated to untreated males. Untreated females mated to males exposed in utero showed decreased fertility at 3 and 5 months of age (36% and 0% pregnancy rate, respectively). Follow up studies indicated that treatment of pregnant mice with decitabine on gestation day 10 was associated with a reduced pregnancy rate resulting from effects on sperm production in the F1-generation.
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. Because of the potential for serious adverse reactions from decitabine in a breastfed child, advise women not to breastfeed while receiving decitabine and for at least 2 weeks after the last dose.
Conduct pregnancy testing of females of reproductive potential prior to initiating decitabine.
Decitabine can cause fetal harm when administered to pregnant women [see Use in Specific Populations (8.1)]. Advise females of reproductive potential to use effective contraception while receiving decitabine and for 6 months following the last dose.
Advise males with female partners of reproductive potential to use effective contraception while receiving treatment with decitabine and for 3 months following the last dose [see Nonclinical Toxicology (13.1)].
Infertility Based on findings of decitabine in animals, male fertility may be compromised by treatment with decitabine. The reversibility of the effect on fertility is unknown [see Nonclinical Toxicology (13.1)].
The safety and effectiveness of decitabine in pediatric patients have not been established.
Of the total number of patients exposed to decitabine in the controlled clinical trial, 61 of 83 patients were age 65 years and over, while 21 of 83 patients were age 75 years and over. No overall differences in safety or effectiveness were observed between these subjects and younger subjects, and other reported clinical experience has not identified differences in responses between the elderly and younger patients, but greater sensitivity of some older individuals cannot be ruled out.
There is no known antidote for overdosage with decitabine. Higher doses are associated with increased myelosuppression including prolonged neutropenia and thrombocytopenia. Standard supportive measures should be taken in the event of an overdose.
Decitabine is a nucleoside metabolic inhibitor. Decitabine is a fine, white to almost white powder with the molecular formula of C8 H12 N4 O4 and a molecular weight of 228.21. Its chemical name is 4-amino-1-(2-deoxy-β-D-erythro-pentofuranosyl)-1,3,5-triazin-2(1H)-one and it has the following structural formula:
Decitabine is soluble in dimethyl sulfoxide; sparingly soluble in water; slightly soluble in ethanol and water (50:50), in methanol and water (50:50), and in methanol. Decitabine for injection, for intravenous use, is a sterile, white to almost white lyophilized cake or powder supplied in a clear colorless glass single-dose vial. Each 20 mL vial contains 50 mg decitabine, 68 mg monobasic potassium phosphate (potassium dihydrogen phosphate) and 11.6 mg sodium hydroxide. Sodium hydroxide is used for pH adjustment.
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
Decitabine has been shown to induce hypomethylation both in vitro and in vivo. However, there have been no studies of decitabine-induced hypomethylation and pharmacokinetic parameters.
Pharmacokinetic (PK) parameters were evaluated in patients. Eleven patients received 20 mg/m2 infused over 1 hour intravenously (treatment Option 2). Fourteen patients received 15 mg/m2 infused over 3 hours intravenously (treatment Option 1). PK parameters are shown in Table 3. Plasma concentration-time profiles after discontinuation of infusion showed a biexponential decline. The clearance (CL) of decitabine was higher following treatment Option 2. Upon repeat doses, there was no systemic accumulation of decitabine or any changes in PK parameters. Population PK analysis (N=35) showed that the cumulative AUC per cycle for treatment Option 2 was 2.3-fold lower than the cumulative AUC per cycle following treatment Option 1.
Table 3 Mean (CV% or 95% CI) Pharmacokinetic Parameters of Decitabine
|Dose||Cmax (ng/mL)||AUC0-INF (ng·h/mL)||T 1/2 (h)||CL (L/h/m2)||AUCCumulative‡ (ng·h/mL)|
|15 mg/m2 3-hr infusion every 8 hours for 3 days (Option 1)*||73.8(66)||163(62)||0.62(49)||125(53)||1332(1010-1730)|
|20 mg/m2 1-hr infusion daily for 5 days (Option 2)†||147(49)||115(43)||0.54(43)||210(47)||570(470-700)|
*N=14, † N=11, ‡ N=35 Cumulative AUC per cycle
The exact route of elimination and metabolic fate of decitabine is not known in humans. One of the pathways of elimination of decitabine appears to be deamination by cytidine deaminase found principally in the liver but also in granulocytes, intestinal epithelium and whole blood.
Patients with Renal Impairment
There are no data on the use of decitabine in patients with renal impairment.
Patients with Hepatic Impairment There are no data on the use of decitabine in patients with hepatic impairment.
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