Intravitreal panitumumab for prevention of myopic axial elongation in highly myopic adult eyes with myopic macular degeneration: Phase 1 study on safety

AbstractPurpose: Recent histomorphometric and clinical studies suggested that axial myopic elongation occurs through an enlargement of Bruch's membrane (BM) in the retroequatorial and equatorial region, leading to a thinning of choroid and sclera at the posterior pole. Thickness of the retina and choriocapillaris and RPE‐density in the macular region and BM thickness in any region remain independent of axial length. The equatorial‐to‐retroequatorial BM enlargement may be caused by an epidermal growth factor (EGF)‐associated RPE activity. Experimental studies in guinea pigs and monkeys showed a reduction in axial elongation by intravitreally applied blockers of EGF family members and the EGF receptor, and an increase in axial elongation by intravitreally applied EGF family members. In a clinical study, the intraocular EGF amount correlated with longer axial length. It led to the hypothesis, that ocular axial elongation is associated with EGF, and that further axial elongation may be prevented by an EGF blockade. We examined here the safety of intravitreally applied panitumumab, an EGF receptor blocker, already in clinical systemic use in oncology for two decades.Methods: The phase‐1 study included highly myopic adult patients with myopic macular degeneration. The eyes received one to two intravitreal injections of 0.6 mg (60 μl), 1.2 mg (120 μl) or 1.8 mg (180 μl) panitumumab.Results: The study included 10 patients (age 57–72 years, axial length: 29.10 mm–32.67 mm). Examined at day 1, 7, and 28 and at 2 and 3 months after the injections, the injected eyes did not show any intraocular inflammation or morphologic or functional changes, assessed by retinal electroretinography, perimetry, optical coherence tomography, tonometry and visual acuity measurement.Conclusions: The preliminary observations of these 10 patients are in agreement with a notion of an intraocular tolerability of panitumumab repeatedly injected intravitreally in doses of 0.6, 1.2 or 1.8 mg.