Severe trastuzumab-induced pneumonitis refractory to steroid therapy.

Trastuzumab has been widely used in breast cancers. Despite its efficacy, trastuzumab-induced pneumonitis (TIP) remains a rare yet potentially fatal complication. While corticosteroids are the mainstay of treatment, steroid-refractory cases pose significant challenges due to the lack of standardised guidelines and limited data on additional therapies. We describe a case of grade 4 TIP in a female in her early 70s, initially managed with steroids and intravenous immunoglobulin, resulting in minimal clinical improvement. Due to the lack of response, advanced immunosuppressive therapy with infliximab was initiated which led to a marked improvement in her condition. This suggests that infliximab may be used to treat severe, corticosteroid-resistant TIP, particularly in cases when conventional therapy is ineffective. The findings obtained here urge additional research to better characterise further interventions like infliximab in TIP therapy and highlight the need for updated guidelines that incorporate advanced immunosuppressive medicines.