Epidermal growth factor receptor antibody and axial elongation in experimental myopia

Purpose To evaluate the effect of intraocularly applied epidermal growth factor receptor (EGFR) antibody panitumumab on axial elongation. Methods This is a preclinical, safety, and efficacy experimental study. Guinea pigs aged 2-3 weeks were fitted with bilateral plano lenses (Group I; n = 10) or underwent bilateral lens-induced myopization (LIM) (Group II; n = 10) with no intravitreal injections. Animals with LIM of Groups III (n = 15), IV (n = 15) and V (n = 15) received three 4-weekly intravitreal injections of panitumumab at doses of 25, 50 and 100 mu g, respectively, into their right eyes, and of phosphate-buffered saline into their left eyes. Results Inter-eye differences in axial elongation (right eye minus left eye at study end) decreased (p < 0.001) from 0.00 +/- 0.02 mm (Group I) and - 0.01 +/- 0.02 mm (Group II) to -0.09 +/- 0.03 mm (Group III), -0.12 +/- 0.03 mm (Group IV) and - 0.17 +/- 0.05 mm (Group V). Interocular choroidal thickness differences (measured by optical coherence tomography) increased (p < 0.01) from Groups I and II to Groups III-V. Western blot analysis showed an increase (p < 0.05) in expression levels of EGFR and its downstream phosphorylated signalling molecule, p-PI3K, in Group II compared to Group I and a decrease in Groups III-V compared to Group II (all p < 0.01). Interocular differences in retinal thickness did not differ significantly (p > 0.05) between the groups. TUNEL staining revealed no significant differences in retinal apoptotic cell density among any groups (all p > 0.05). Conclusions Intravitreally administered panitumumab in young guinea pigs with LIM resulted in a dose-dependent and treatment frequency-dependent reduction in axial elongation, supporting the role of EGFR signalling in axial elongation.