Gefitinib-induced Myositis: A Novel Case Report

Yakugaku Zasshi. 2023;143(7):617-620. doi: 10.1248/yakushi.23-00007.ABSTRACTChemotherapy-induced myositis is a severe adverse event caused by chemotherapeutic agents such as immune checkpoint inhibitors (ICIs) or cytotoxic agents. We experienced a patient with gefitinib-induced myositis with symptoms of muscle cramps and stiffness in the limbs, and reported the treatment process. A 70-year-old woman received four courses of carboplatin (CBDCA)+pemetrexed (PEM)+gefitinib (intravenous CBDCA area under the curve (AUC) 5 and PEM 500 mg/m2, every 3 weeks, and oral gefitinib 250 mg daily), for epidermal growth factor receptor (EGFR) mutation-positive stage IV lung cancer treatment; followed by seven courses of PEM+gefitinib, and continued gefitinib monotherapy thereafter. Myositis occurred 5 months after the initiation of gefitinib monotherapy. She developed strong limb cramps despite regular oral administration of 400 mg acetaminophen three times a day and complained of pain on a numeric rating scale of 10/10. Her creatine kinase (CK) was elevated from the second course of CBDCA+PEM+gefitinib but was stable at grade 1-2 thereafter. However, the muscle symptoms disappeared with CK normalization within a few days of gefitinib discontinuation due to disease progression. The Naranjo Adverse Drug Reaction Scale score was 6, suggesting a probable association. Osimertinib (an EGFR tyrosine kinase inhibitor)-induced myositis has been reported, but similar events were first observed with g...
Source: Yakugaku Zasshi : Journal of the Pharmaceutical Society of Japan - Category: Drugs & Pharmacology Authors: Source Type: research