[Corneal melting under PD-1/PD-L1 inhibition]

Immune checkpoint inhibitors (ICIs) are increasingly used in oncological therapy. Ocular immune-mediated adverse events are rare but may involve the cornea and progress to corneal melting or perforation. We report two male patients with metastatic malignancies who developed severe corneal disease under ICI therapy. In a 65-year-old patient with metastatic renal cell carcinoma, recurrent conjunctivitis and epithelial defects initially occurred under pembrolizumab (programmed cell death protein 1 inhibitor, PD-1 inhibitor). During the further course, bilateral anterior stromal thinning with subepithelial scarring was observed. Stabilization was achieved under intensified topical therapy with N-acetylcysteine and cyclosporine A. A 55-year-old patient with metastatic non-small cell lung cancer developed bilateral corneal erosions under atezolizumab (programmed death ligand 1 inhibitor, PD-L1 inhibitor), with rapid progression to paracentral ulcerations, corneal perforation in the right eye and a descemetocele in the left eye. Given additional systemic tumor therapy, previous whole-brain radiotherapy and lagophthalmos, a multifactorial etiology was assumed. Penetrating keratoplasty was performed in the right eye and amniotic membrane transplantation in the left eye. In patients presenting with new epithelial defects, ulcerations or stromal thinning under ICI therapy, ICI-associated corneal melting should be considered as a differential diagnosis. Early intensive topical therapy and interdisciplinary management are essential to limit progression.