Alleviation of Allergic Rhinoconjunctivitis Symptoms in Participants Treated with a 0.005% Tacrolimus Eye-Drop Solution

Purpose: This randomized, placebo-controlled, crossover, double-blind trial aimed to evaluate the efficacy and safety of Tacrosolv, a novel 0.005% tacrolimus eye-drop solution, in adults with grass pollen–induced allergic conjunctivitis. Methods: A total of 64 adult participants were randomized to receive 2.5 µg or 5 µg tacrolimus/eye/day or placebo treatment for 8 days, with grass pollen exposure on day 1 and day 8. After a 2-week washout period, placebo participants crossed over to Tacrosolv treatment and vice versa, with repeated treatment and exposure. During exposure, participants recorded ocular, nasal, and respiratory allergy symptoms every 15 minutes. The primary endpoint was the mean total ocular symptom score (TOSS) on day 8. Objective ocular safety parameters were assessed before, during, and after exposure. Adverse events were recorded throughout the study. Results: On day 8, high-dose Tacrosolv reduced the TOSS compared to placebo towards the end of exposure (p<0.05 at time points 3 hours, 45 minutes and 4 hours). A 26% reduction in baseline adjusted TOSS from day 1 to day 8 was observed in participants treated with high-dose Tacrosolv, whereas placebo-treated participants showed no difference in TOSS between day 1 and day 8. Nasal symptoms were reduced on both day 1 and day 8 in participants treated with high-dose Tacrosolv (p<0.05). No safety concerns were raised. All adverse events were resolved within the study period. Conclusion: High-dose Tacrosolv is safe and effective for alleviating symptoms of allergic rhinoconjunctivitis. Trial Registration: NCT04532710; EudraCT No. 2019-002847-62.