The Food and Drug Administration (FDA) has approved the kinase inhibitor ibrutinib (Imbruvica) to treat chronic graft-versus-host disease in pediatric patients at least one year of age when one or more systemic therapies have failed. Ibrutinib was previously approved to treat adults with mantle cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma with a 17p deletion, Waldenstrom macroglobulinemia, marginal zone lymphoma, and chronic graft-versus-host disease after previous treatment failure.

Ibrutinib's efficacy for this new indication was determined in an open-label, multicenter, single-arm trial of 47 pediatric and young adult patients, ages one year to less than 22 years, with moderate or severe disease. The main efficacy outcome measure was overall response rate, including complete or partial response, through week 25. The overall response rate by week 25 was 60% and the median duration of response was 5.3 months. The median time from first response to death or initiation of new systemic therapies for chronic graft-versus-host disease was 14.8 months.

Ibrutinib's labeling warns of the risk of hemorrhage, infections, cardiac arrythmias, cardiac failure and sudden death, hypertension, cytopenia, secondary primary malignancies, tumor lysis syndrome, and embryo-fetal toxicity. The most common adverse effects include laboratory abnormalities (anemia and thrombocytopenia), musculoskeletal pain, pyrexia, pneumonia, abdominal pain, stomatitis, diarrhea, and headache.

Ibrutinib is taken orally and is available as capsules, tablets, and oral suspension. Tablets and capsules should not be opened, broken, crushed, or chewed. When an oral suspension is prescribed for a child, the nurse should teach the parents how to mix the oral suspension prior to administration and to read the detailed instructions that come with the prescription. Because of cytochrome P450 isoenzyme drug interactions, drinking grapefruit juice, eating grapefruit, or eating Seville oranges (often used in marmalades) should be avoided, as these may increase the circulating levels of ibrutinib, increasing the risk of adverse effects. Nurses should teach parents and their children about the potential adverse effects of ibrutinib therapy and to report them to the prescriber if they occur.

For complete prescribing information for ibrutinib, go to http://www.accessdata.fda.gov/drugsatfda_docs/label/2022/217003s000lbl.pdf.