Drug-Induced Lung Injury With Drug Eruption Due to Apalutamide Followed by Switch to Bicalutamide: A Case Report.

Androgen receptor inhibitors (ARIs) are the first-line treatment for castration-resistant prostate cancer. However, there have been limited reports on drug-induced lung injury (DILD) and other serious adverse events. We report the case of an 85-year-old Japanese man who was diagnosed with prostate cancer and initiated treatment with apalutamide. Approximately two months later, he developed DILD accompanied by a drug eruption. After recovery, the patient was switched to bicalutamide, and the drug eruption recurred; however, DILD did not develop. We suspected cross-reactivity in the drug eruption but not in the interstitial lung injury. This case suggests that medical practitioners should be careful concerning the development of drug eruption and DILD when switching from one ARI to another when DILD develops in an ARI.