Ocular toxicity (keratopathy, blurred vision)

ADCs with MMAF or other non-cleavable tubulin payloads (belantamab mafodotin) and tissue factor ADCs (tisotumab vedotin) cause keratopathy in most patients because payload reaches the corneal epithelium, requiring ophthalmology checks before each dose, lubricating drops and dose modification, and prompting the REMS programme and dose reductions that followed belantamab's re-approval. MEK inhibitors cause transient serous retinopathy, EGFR inhibitors cause conjunctivitis and trichomegaly, and checkpoint inhibitors cause uveitis. Ocular toxicity has ended some ADC programmes and is a key design consideration for payload and linker choice.