Pirenzepine 2% Ophthalmic Gel Retards Myopic Progression in 8-12 Year Old Children

Abstract

Abstract: : Purpose: Pirenzepine (PIR), a relatively selective M1-muscarinic antagonist, reduces form-deprivation myopia in animal models by attenuating axial length. A 2% ophthalmic gel has been shown to be safe in children when used twice daily for 28 days. This study examines the safety and efficacy of PIR 2% gel in reducing myopic progression in healthy children. Methods: In a multi-centered (n=13), randomized, controlled clinical US trial, 174 children aged 8-12 years inclusive were assigned on a 2:1 basis to receive either PIR 2% gel (n=117) or placebo (n=57) twice daily for one year. Entry criteria included visual acuity > 20/25, refractive error of -0.75 to -4.00 D spherical equivalent, and < 1.00 D cylinder in each eye. Primary outcome measure was cycloplegic autorefraction at 12 months. Ocular and systemic signs and symptoms were monitored for safety. Results: Mean baseline refractive error was -2.10 D in the PIR group and -1.93 D in the placebo group (p=0.221). Mean myopic progression at 12 months was -0.26 D with PIR and -0.53 D with placebo (p<0.001). Only 2% of PIR subjects had > 1D of myopic progression at one year, versus 20% of the placebo group (p<0.001). Frequency of adverse events was similar between the two groups (98% PIR vs 93% placebo, p=0.091). Treatment was generally well tolerated; however, 11% of PIR subjects withdrew from the study due to adverse events, versus none of the placebo subjects. The most common adverse events were gel residue on the eyelids, blurred vision at near, and asymptomatic conjunctival reactions. Conclusions: PIR 2% gel used twice daily in moderately myopic children reduced the rate of myopic progression at one year by 50% (0.26 D) compared to placebo. Safety profile was acceptable, and no serious adverse events related to study medication occurred. Phase 3 studies will examine varying doses of PIR used over a broader age range. PIR is an exciting, novel, and effective approach to the pharmacologic treatment of myopia.

Keywords: myopia • refractive error development