Corneal features in trastuzumab emtansine treatment: not a rare occurrence.

PURPOSE: Ado-trastuzumab emtansine (T-DM1/Kadcyla® ;Genentech) is an antibody-drug conjugate used in the treatment of human epidermal growth factor receptor-2-positive metastasized breast cancer. Few studies report a spectrum of corneal changes in patients treated with this drug. Our aim is to specify the nature and prevalence of corneal features of T-DM1 treatment in order to formulate guidelines as to which findings necessitate systemic treatment cessation or dose reduction.

METHODS: We performed a cross-sectional, prospective study in all patients currently treated with T-DM1 or recently stopped in Ghent University Hospital, Belgium.

RESULTS: A total of 12 patients completed a full ophthalmic workup. Ten patients were currently using T-DM1, and two patients had recently (< 10 weeks) stopped treatment because of clinical non-response. Twenty eyes of 10 patients currently on T-DM1-treatment all exhibited coarse cystoid lesions to the deep corneal epithelial cells, primarily in the midperipheral area, both biomicroscopically and on confocal microscopy. The two patients who stopped treatment, displayed no corneal epithelial changes. Only three patients reported symptoms which were attributed to other ocular factors, likely not to be related to T-DM1 treatment.

CONCLUSIONS: This case series shows that asymptomatic, low-grade corneal epithelial changes are hallmark features in T-DM1-treatment and should not alarm clinicians. These findings are relatively stationary, reversible and thus do not require ocular treatment or cessation of systemic treatment.