Severe Psychiatric Symptoms in a Patient With EGFR Exon-20 Insertion Mutation Receiving Mobocertinib: A Case Report

Tyrosine kinase inhibitor therapy is an established standard of care for patients with NSCLC with EGFR mutations, but a worse prognosis has been observed in patients with specific EGFR exon-20 insertion mutations. Mobocertinib (TAK-788) is a novel tyrosine kinase inhibitor developed to target EGFR exon-20 insertion and has exhibited promising response rates and acceptable safety in phase 1 and 2 trials. We report a case of a 59-year-old woman with metastatic NSCLC and EGFR exon-20 mutation responsive to mobocertinib therapy, who developed severe depression and catatonia approximately 4 months after mobocertinib initiation, ultimately necessitating its permanent discontinuation. Given the observed severe depression in this case report, we recommend that, for patients on mobocertinib who develop neuropsychiatric adverse effects, strong consideration should be given for dose interruption or discontinuation.