Osimertinib rechallenge under steroid protection following osimertinib-induced pneumonitis: three case studies

Osimertinib is a third-generation tyrosine kinase inhibitor that became the preferred first-line treatment option for metastatic non-small cell lung cancer with sensitizing epidermal growth factor receptor mutations. Drug-induced pneumonitis is known to occur with osimertinib. In case of severe pneumonitis, discontinuation of treatment and therapy with corticosteroids is recommended, and a treatment switch is usually performed. We herein report the treatment course in three patients who were rechallenged with osimertinib under steroid protection following an osimertinib-induced pneumonitis. All our patients were initially re-exposed to a lower dose of osimertinib. Two patients were successfully rechallenged under prednisolone protection. The third patient, who was initially retreated with osimertinib without steroid protection, suffered from a recurrent pneumonitis, and was later rechallenged successfully under steroid protection. Our case series indicates that rechallenge with osimertinib following recovery from osimertinib-induced pneumonitis allows a successful rechallenge in individual cases when alternative treatment options are lacking. Concomitant steroids appear to protect against flares of pneumonitis during rechallenge.