Purpose: This randomized, placebo-controlled, crossover, doublel-blind, single site trial was aimed to evaluate efficacy and safety of Tacrosolv, a novel eye drop solution containing solubilized tacrolimus, in adult participants with grass pollen induced allergic conjunctivitis. Methods: 64 adult participants with proven grass pollen allergy were randomized to either 2.5 ug or 5 ug tacrolimus/eye/day or placebo treatment for 8 days. Allergic symptoms were induced by 4h grass pollen exposure on day 1 and day 8. After a 2-week wash-out period, placebo participants crossed over to high or low dose and vice versa, and 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 (AEs) were recorded throughout the study. Results: On Day 8, TOSS was reduced towards the end of exposure in participants receiving Tacrosolv high dose compared to placebo (p<0.05 at timepoints 3h45min and 4h). Accordingly, intensity of the single ocular symptoms like redness and watery eyes was reduced versus placebo by end of exposure on Day 8. A 26% reduction of 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. Interestingly, a significant reduction of total nasal symptoms, mainly itching and sneezing, was seen both on day 1 and day 8 in participants treated with high dose Tacrosolv (p<0.05). No safety concerns were raised upon ocular assessments by the investigator like redness of the eye, corneal and conjunctival staining. All AEs were resolved within the study period. Conclusion: Treatment with Tacrosolv at the dose and frequency studied is safe and alleviates symptoms in participants suffering from allergic rhinoconjunctivitis. Trial registration: NCT04532710; EudraCT No. 2019‐002847‐62 Keywords: Allergic rhinoconjunctivitis, tacrolimus, ocular redness, ocular itching, topical administration, clinical trial.  

NUM, SS, CS, HD and EPG are employees of Marinomed Biotech AG. MS has received consulting fees from Marinomed biotech AG. WG and ML have received honoraria from Marinomed Biotech AG. The other authors have no competing interests in this work.

NCT04532710

This study was funded by Marinomed Biotech AG.

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The study was conducted in Austria in accordance with the Declaration of Helsinki on Ethical Principles for Medical Research Involving Human Subjects, the International Council for Harmonisation Guideline on Good Clinical Practice, and all applicable local regulatory requirements and laws. The study was approved by the Ethics Committee of the City of Vienna (protocol code TCS_19_02, EK 19-275-1219). Informed consent was obtained from all study participants.

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All data produced in the present study are available upon reasonable request to the authors