Mid‐term clinical outcomes of collagen‐phosphorylcholine cornea substitutes for therapeutic anterior lamellar keratoplasty

Purpose To assess safety and efficacy of biosynthetic collagen‐phosphorylcholine implants as corneal substitutes in patients with severe pathologies for whom human donor cornea transplantation carries a high risk of rejection. Methods Recombinant human collagen type III and 2‐methacryloyloxyethyl‐phosphorylcholine were fabricated into collagen‐MPC corneal substitutes (CMCS). CMCS were implanted into the corneas of 8 patients (3 Phase 0, 5 Phase 1 patients) by anterior lamellar keratoplasty (ALK). The pathologic areas were excised and replaced with CMCS grafts. Benchmark patients were grafted by conventional ALK and human amniotic membrane (HAM). Follow‐up ranged from 12 to 36 months. Results Pre‐operatively, CMCS patients had persistent ulcers or recurrent erosions from chemical or thermal burns, keratitis or failed penetrating grafts. All patients were relieved of pain and photophobia post‐operation. 7/8 CMCS grafted corneas epithelialized within 4–50 weeks leading to improved visual acuity in 4/8 patients. Neovascularisation developed in 2/8 patents. Ten patients with similar conditions grafted by conventional ALK took 2–12 weeks to epithelialize. Neovascularisation developed in 9/10 patients, and visual acuity improved in 3/10 patients. In HAM patients, corneas epithelialized within 2–3 weeks, neovascularization developed in 7/10 patients, vision improved in 4/10 patients. Conclusions These results suggest that CMCS are safe in patients. In addition, they appeared to withstand the adverse microenvironment within corneas with severe pathology, and restored corneal integrity in high risk keratoplasty patients. Further clinical testing is needed to verify these early results.