Refractive shifts due to belantamab mafodotin–associated corneal toxicity

Introduction: This report describes a case of belantamab mafodotin–associated corneal toxicity. The patient presented with refractive changes, which has not been previously reported with this condition. Patient and Clinical Findings: A 58-year-old man with refractory multiple myeloma and myopia presented for screening before the initiation of belantamab mafodotin (belamaf or Blenrep, an antibody-drug conjugate [ADC] with known corneal toxicity). After 1 infusion, he returned complaining of loss of uncorrected near vision and was found to have bilateral keratopathy with microcyst-like epithelial changes (MECs) in the midperipheral cornea. Diagnosis, Intervention, and Outcomes: A hyperopic refractive error was seen with manifest refraction, and central flattening was seen on corneal topography. The patient was diagnosed with corneal epithelial toxicity secondary to belamaf. The medication was discontinued, and the MECs migrated centrally causing a refractive shift and eventually resolving. The patient was ultimately happy with his visual outcome because his uncorrected vision returned to baseline. Conclusions: Any vision changes in patients on ADCs should be carefully worked up, including with manifest refraction and appropriate testing, because they may indicate early ocular side effects that can be treated. This case introduces evidence of hyperopic and myopic changes directly correlating with slitlamp examination findings and imaging of a patient with belamaf-induced MECs.