Aldeyra’s anti-allergy eyedrop sails through first phase 3 trial, boosting stock price by two-thirds

Aldeyra Therapeutics has aced the first phase 3 trial for its reproxalap eyedrop for allergic conjunctivitis, sending its stock up at least 66% in premarket trading.

The company also announced it secured up to $60 million in new financing, through a loan agreement with Hercules Capital—to help carry reproxalap through a second phase 3 study, as well as fund the other clinical programs in its portfolio.

The small-molecule reproxalap has a different mechanism of action compared to corticosteroids and antihistamines—it’s designed to reduce inflammation by binding to free-floating, organic aldehyde compounds that can trigger the body’s immune response.

The study, named ALLEVIATE, compared 0.25% and 0.5% solutions of reproxalap to placebo using an Allergen challenge chamber, which maintains controlled levels of pollens and other seasonal irritants.

With about 100 patients randomized into each of the study’s three arms, the trial met its primary and key secondary endpoint in both concentrations, with significant reductions in ocular itching seen within 10 minutes to an hour of use. Reproxalap also showed significant improvements in itch scores and response rates.

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“Consistent with positive results from five prior phase 2 clinical trials in ocular inflammation, today's announcement confirms the potential of reproxalap as a novel and clinically meaningful approach for the treatment of allergic conjunctivitis,” Aldeyra President and CEO Todd Brady said in a statement.

And although participants with active dry eye disease were excluded from the trial, Aldeyra believes its findings could still be relevant in the lucrative indication.

The company estimates that about half of patients with allergic conjunctivitis also suffer from ocular dryness—where reproxalap is currently being studied in a separate phase 3 trial, launched this year. Last September, the drug successfully completed a phase 2b trial in dry eye disease, as the company works to secure a place for reproxalap next to Allergan’s Restasis and Shire’s Xiidra treatments.

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In the latest trial, both concentrations of reproxalap demonstrated an anti-inflammatory profile distinct from standard antihistamine therapies, which the company said supports its unique mechanism of action.

"There is a large allergic conjunctivitis patient population that is underserved by currently available medications," said David Clark, Aldeyra’s chief medical officer. In addition, there were no reported adverse events, aside from mild site irritation.

"The ALLEVIATE results suggest the potential of topical ocular reproxalap as a novel, safe and effective therapeutic option that could be used to complement existing therapy before resorting to corticosteroids, which can lead to serious ocular toxicity," Clark said.

Before moving forward to the next clinical test, the company is currently evaluating its options for measuring ocular itching triggered by wider, environmental exposure, compared to the controlled allergen chamber. The company plans to meet with the FDA in the second half of this year to discuss the latest trial results and what the agency needs to see before submitting the drug for approval.