Reproxalap may be a viable new therapy option for patients with allergic conjunctivitis, according to a study published in Clinical Ophthalmology

Researchers used an environmental exposure chamber to simulate real-life airborne pollen conditions with consistent levels of aerosolized ragweed grains per cubic meter in a double-masked study conducted between October 2018 and April 2019. Of 423 patients (≥18 years of age, with ≥2 years of moderate to severe allergic conjunctivitis), 70 experienced significant redness and itching in the specially controlled environment. A 3-way crossover design randomized participants 1:1:1 to receive either 0.25%, reproxalap, 0.5% reproxalap, or a placebo. Investigators instilled drops 1 minute before chamber entry and at 90 minutes intervals over the course of the 3.5-hour session. Participants were monitored for 62 minutes after exiting the chamber.

Reproxalap proved effective in reducing symptoms of tearing (P <.0001) and itching (P <.0001), and lessened conjunctival redness (P <.0001), compared with the placebo. 

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“The prophylactic and treatment activity of reproxalap were evident within minutes of administration, and reproxalap was generally [the superior] vehicle throughout the duration of the chamber exposure period and over all time points assessed after chamber exit,” according to the investigators. “These results imply that reproxalap is active before, during, and after allergen exposure, potentially addressing real-world clinical challenges faced by patients with allergic conjunctivitis.”

Study limitations include a relatively small sample size and single center design.

Disclosure: This trial was funded by Aldeyra Therapeutics, Inc. Study authors also declared affiliations with biotech, pharmaceutical, and/or clinical research organizations. Please see the original reference for a full list of authors’ disclosures. 


Clark D, Karpecki P, Salapatek AM, Sheppard JD, Brady TC. Reproxalap improves signs and symptoms of allergic conjunctivitis in an allergen chamber: a real-world model of allergen exposure. Clin Ophthalmol. 2022;16:15–23. doi:10.2147/OPTH.S345324

This article originally appeared on Optometry Advisor