Pediatric Use of Recombinant Human Nerve Growth Factor 20 μg/mL Eye Drops (Cenegermin) for Bilateral Neurotrophic Keratopathy in Congenital Corneal Anesthesia

Can Nerve Growth Factor (NGF) Be a Treatment Option for Pediatric Eye Diseases?

A critical review of mechanisms of action and pharmacokinetics of nerve growth factor (NGF), including topical administration, and the studies showing the NGF treatment for anterior and posterior segment diseases in adult and pediatric population are summarized in our paper. Nerve growth factor is commonly used for many different ocular conditions in the adult population to promote nerve regeneration or cellular rescue. Clinical trials for recombinant human NGF have also treated several challenging ocular conditions, such as neurotrophic keratopathy, glaucoma, and retinitis pigmentosa with cystoid macular edema. The safety and efficacy of NGF have been demonstrated in pediatric patients as well. This leads us to consider new applications of NGF for the treatment of pediatric eye diseases.

A, B, C's of Trk Receptors and Their Ligands in Ocular Repair

Neurotrophins are a family of closely related secreted proteins that promote differentiation, development, and survival of neurons, which include nerve growth factor (NGF), brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4. All neurotrophins signal through tropomyosin receptor kinases (TrkA, TrkB, and TrkC) which are more selective to NGF, brain-derived neurotrophic factor, and neurotrophin-3, respectively. NGF is the most studied neurotrophin in the ocular surface and a human recombinant NGF has reached clinics, having been approved to treat neurotrophic keratitis. Brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4 are less studied neurotrophins in the ocular surface, even though brain-derived neurotrophic factor is well characterized in glaucoma, retina, and neuroscience. Recently, neurotrophin analogs with panTrk activity and TrkC selectivity have shown promise as novel drugs for treating dry eye disease. In this review, we discuss the biology of the neurotrophin family, its role in corneal homeostasis, and its use in treating ocular surface diseases. There is an unmet need to investigate parenteral neurotrophins and its analogs that activate TrkB and TrkC selectively.

Recombinant Human Nerve Growth Factor for Pediatric Neurotrophic Keratopathy

ABSTRACT

A 4-year-old boy presented with right neurotrophic corneal ulcer, lagophthalmos, and facial palsy 8 months after neurosurgery for synchronous brain tumors. Initial treatment with topical antibiotics, topical corticosteroids, lubrication, and lateral tarsorrhaphy successfully treated the corneal epithelial defect; however, the cornea continued to demonstrate diffuse epitheliopathy and a dense stromal opacity and remained insensate on Cochet-Bonnet esthesiometry. After a course of topical cenegermin, central corneal sensation normalized, and the corneal epitheliopathy was markedly improved. Two years after the completion of cenegermin, corneal sensation was maintained; there were no recurrences of epithelial defects, and the stromal opacity had markedly improved. In vivo confocal microscopy (IVCM) demonstrated the presence of subbasal corneal innervation. This report highlights the safety and prolonged effects of cenegermin for the treatment of pediatric iatrogenic neurotrophic keratopathy, as evidenced by the clinical course and IVCM.

Maternal serum eye drops to treat bilateral neurotrophic keratopathy in congenital corneal anesthesia: Case report and literature review

Purpose

To report the feasibility and the successful outcomes of a pediatric neurotrophic keratopathy (NK) owing to congenital corneal anesthesia (CCA) treated with allogeneic serum eye drops obtained from the mother as the only therapy.

Observations

A 18-month-old girl with generalized pain insensitivity presented with a large epithelial defect in the right eye (RE) and superficial punctate keratopathy (SPK) in the left eye (LE). Corneal sensitivity was completely absent in both eyes (BE). Peripheral serum eye drops obtained from the mother was prescribed and administered every 2 hours in BE. Two weeks after the beginning of treatment, compete healing of the epithelial defect in the RE was obtained, while the severity of the SPK in the LE markedly improved; in parallel, conjunctival hyperemia disappeared in BE. The treatment was continued over the course of 3 months with good tolerability and neither signs of recurrence of the epithelial defect nor other complications were noted.

Conclusions and Importance

Allogeneic serum eye drops obtained from the mother are effective in treating pediatric NK owing to CCA. This treatment may represent a readily available and inexpensive option when topical nerve growth factor is unavailable or corneal neurotization is not feasible.

Neurotrophic Keratitis Due to Congenital Corneal Anesthesia with Deafness, Hypotonia, Intellectual Disability, Face Abnormality and Metabolic Disorder: A New Syndrome?

Neurotrophic keratitis is a rare degenerative disease of the cornea that can lead to corneal ulceration, scarring, and significant visual impairment. It most commonly occurs in adults and is rarely diagnosed in children. Congenital corneal anesthesia is an extremely rare condition that requires appropriate ophthalmologists’ attention in making diagnosis and treatment decisions. This condition usually presents in infancy or early childhood and is characterized by rare blinking rate, decreased tearing or a corneal ulcer that is unresponsive to treatment. In this case report, we describe a patient with multiple systemic and neurological disorders who presented to the ophthalmology department due to corneal erosion unresponsive to treatment. Brain magnetic resonance imaging confirmed bilateral trigeminal hypoplasia and the diagnosis of neurotrophic keratopathy due to bilateral congenital corneal anesthesia was made. The discrepancy between clinical signs and symptoms or treatment non-response in cases of corneal erosions should alert the ophthalmologists to suspect trigeminal dysfunction. MRI is the gold standard to confirm congenital corneal anesthesia and to differentiate from other possible neurotrophic keratitis causes.

Corneal Neurotization Using the Great Auricular Nerve for Bilateral Congenital Trigeminal Anesthesia

PURPOSE

The purpose of this study was to describe an indirect corneal neurotization (CN) technique for congenital bilateral trigeminal anesthesia using the greater auricular nerve (GAN) as a donor.

METHOD

CN was performed to preserve the integrity of the only seeing eye in a 4-year-old boy with pontine tegmental cap dysplasia and bilateral trigeminal anesthesia. He had recurrent corneal ulceration and scarring despite full medical treatment. The GAN was used as a donor, and the sural nerve was harvested and used as a bridge which was tunneled to the sub-Tenon space in the inferior fornix. The fascicles were distributed into the 4 quadrants and sutured to the sclera near the limbus.

RESULT

This technique resulted in providing corneal sensation and improving stability of the epithelium. Corneal opacity gradually decreased allowing significant visual improvement evidenced in the early postoperative months.

CONCLUSIONS

Using the GAN technique for CN bypasses trigeminal innervation and has the potential to improve corneal sensation. The GAN is a large caliber nerve and provides a large amount of axons and robust neurotization. This technique would be desirable for cases with bilateral congenital trigeminal anesthesia, such as pontine tegmental cap dysplasia.

Topical cenegermin 0.002% for pediatric neurotrophic keratopathy

PURPOSE

To evaluate the efficacy and safety of cenegermin 0.002% ophthalmic drops in the management of pediatric neurotrophic keratopathy (NK).

METHODS

Retrospective chart review of children under the age of 18 years diagnosed with NK at Boston Children's Hospital/Massachusetts Eye and Ear Infirmary and treated with topical cenegermin 0.002% ophthalmic solution between June 2018 and June 2021 was performed. Data collection included etiology of NK, age at time of initiation of topical cenegermin, laterality, ethnicity, gender, history of previous ocular therapy, pre- and post-therapy best corrected visual acuity, pre- and post-therapy cornea examination, any adverse events from topical cenegermin, associated ocular conditions, and history of ocular surgeries.

RESULTS

The current study includes four eyes of four pediatric patients with a mean age of 4.5 ± 2.0 years at the time of initiation of topical cenegermin therapy. The mean time from NK diagnosis until start of topical cenegermin drops was 5.2 ± 4.3 months and mean follow-up time was 15 ± 9.6 months. In all four patients, marked improvement in epitheliopathy was demonstrated after completion of therapy. Best corrected visual acuity was measurable in 3 eyes of 3 patients, and it improved from a mean of 0.07 ± 0.01 to a mean of 0.29 ± 0.26 (P = 0.3). No adverse events related to cenegermin therapy were noted.

CONCLUSION

Topical cenegermin was effective in improving corneal healing for pediatric NK.

Neurotrophic Keratitis in a Pediatric Patient With Goldenhar Syndrome and Trigeminal Aplasia Successfully Treated by Corneal Neurotization

Herein, the authors report an unusual case of a 6-year-old boy with right-sided Goldenhar syndrome and trigeminal nerve aplasia who developed neurotrophic keratopathy (NK). Despite the use of therapeutic contact lenses and multiple temporary tarsorrhaphy, NK worsened showing a central corneal scar, neovascularization, and significant stromal thinning, with risk of corneal perforation. Cochet-Bonnet esthesiometry revealed complete corneal anesthesia. To minimize additional corneal complications, the patient underwent indirect corneal neurotization by a sural nerve autograft anastomosed to the contralateral supratrochlear nerve. At 24-month follow up, no epithelial defects, complications, or recurrence were observed. Significant improvements in corneal sensitivity with esthesiometry score of 20 mm and reflex blinking were achieved. This case highlights corneal anesthesia should be suspected among Goldenhar syndrome ophthalmologic abnormalities and monitored before corneal changes become irreversible. Since corneal neurotization can successfully improve corneal sensation, it could be considered as an early therapeutic option to avoid refractory NK.