The Food and Drug Administration has now approved azacitidine (Vidaza) to treat juvenile myelomonocytic leukemia (JMML), a rare form of blood cancer mostly affecting children under four years of age. Azacitidine was previously approved to treat adults with the following myelodysplastic syndrome subtypes: refractory anemia or refractory anemia with ringed sideroblasts, refractory anemia with excess blasts, refractory anemia with excess blasts in transformation, and chronic myelomonocytic leukemia.

Azacitidine is believed to cause antineoplastic effects by inducing hypomethylation of DNA (which refers to the loss of the methyl group in the 5-methylcytosine nucleotide) and direct cytotoxicity on abnormal hematopoietic cells in the bone marrow. The cytotoxic effects cause rapidly dividing cells to die. Cells not rapidly dividing are less affected by azacitidine.

Azacitidine's efficacy was evaluated in an international, multicenter, open-label study of the drug's pharmacokinetics, pharmacodynamics, safety, and activity prior to hematopoietic stem cell transplantation in 18 pediatric patients with JMML. Patients were treated with IV azacitidine for a minimum of three 28-day cycles. The main efficacy outcome measures were clinical complete remission or clinical partial remission at three months (cycle 3, day 28). Half the patients had a confirmed clinical response, three had complete responses, and six had partial responses.

The most common adverse effects of the drug when used to treat JMML were pyrexia, rash, upper respiratory tract infections, and anemia. Azacitidine's label also carries the following warnings and precautions: anemia, neutropenia, and thrombocytopenia; hepatotoxicity; renal toxicity; tumor lysis syndrome; and embryo-fetal toxicity.

Nurses caring for children receiving azacitidine should monitor them carefully for hepatic and renal toxicity. Nurses should assess serum creatinine and electrolytes at baseline and during treatment. If unexplained drops in serum bicarbonate (< 20 mEq/L), elevations of blood urea nitrogen, or elevations in serum creatinine are noted, the provider should be notified, as the dose may need to be reduced. Pediatric patients with JMML and preexisting hepatic impairment were not included in the clinical trial, so the effect on this group is unstudied and unknown. Red blood cell, white blood cell, and platelet counts should be assessed closely, and indications of anemia, neutropenia, or thrombocytopenia should be reported to the provider.

For complete prescribing information for azacitidine, go to http://www.accessdata.fda.gov/drugsatfda_docs/label/2022/050974s034lbl.pdf.