Supplementary Material for: Bilateral Paracentral Corneal Melting and Left-Eye Perforation under Tobemstomig Novel Treatment

Introduction: We present a rare occurrence of bilateral corneal melting and a left-eye corneal perforation in an oncologic patient undergoing a new biological therapy. Case Presentation: A 63-year-old male with a two-day history of a painful left red eye and bilateral visual impairment was enrolled in a multicenter phase-II study comparing tobemstomig/RO7247669, a PD1-LAG3 bispecific antibody, with nivolumab. Clinical examination revealed a bilateral central corneal thinning, and corneal OCT imaging indicated a significant stromal thinning of 124 μm in the right eye and a central corneal perforation of 286 μm in the left eye. Subsequently, the patient underwent surgical intervention involving an autologous partial scleral patch with a Gundersen conjunctival flap in the left eye, alongside a comprehensive topical and systemic treatment regimen. Due to this immune-related adverse event, the patient was excluded from the clinical trial subsequently later revealing he had been on the bispecific treatment. Conclusion: While immune checkpoint inhibitors hold promise in oncology, they can lead to ocular surface issues, including dry-eye keratitis and, in severe cases, anterior segment thinning culminating in corneal perforation. Timely withdrawal of immunotherapy, coupled with multi-level treatment involving anti-inflammatory and corneal healing approaches, is crucial. In cases of corneal perforation, surgical intervention such as cyanoacrylate application or tectonic surgery becomes imperative.