Report. Phase I trial of recombinant human nerve growth factor for neurotrophic keratitis

Neurotrophic keratitis/keratopathy (NK), a rare degenerative corneal disease, lacks effective pharmacologic therapies.1 Because NK pathology involves trigeminal nerve damage and loss of corneal innervation, nerve growth factor (NGF) is surmised to promote healing of NK.2 Preliminary studies with murine NGF demonstrated efficacy for treating corneal neurotrophic ulcers;3 however, the complex tertiary structure of NGF has complicated the production of recombinant human NGF (rhNGF) suitable for clinical development. To this end, we developed an Escherichia coli–derived rhNGF formulation that demonstrated to be well tolerated and safe for topical ophthalmic use in a phase I study in healthy volunteers.4 We report phase I results of topical rhNGF for patients with moderate-to-severe NK