Running the enrollment numbers on ophthalmic clinical trials in the United States

SIGNIFICANCE This is one of the first reports to summarize the enrollment metrics for ophthalmology trials completed in the United States (US). PURPOSE This study aimed to describe US ophthalmology clinical trial enrollment metrics to facilitate planning and budgeting of US Food and Drug Administration–regulated ophthalmological drugs trials. METHODS A GlobalData PLC search was conducted on or before February 27, 2024, to evaluate the clinical trial landscape for completed ophthalmology clinical trials conducted in the US. The primary search contained only the term “ophthalmology,” which was restricted to trials that were completed and were conducted within the US. Trials were classified as multicenter when trials included three sites or more, and when the enrollment search resulted in ≥30 multicenter trials for an individual indication, enrollment data were further broken down by Food and Drug Administration trial phase. RESULT The search yielded 2229 trials, which analyzed 980 different drugs produced by 854 different sponsors. The most common indications evaluated in US trials were macular degeneration, glaucoma, macular edema, allergies, and keratoconjunctivitis. Multicenter trials by indication had an overall median enrollment period range of 4.8 to 35.1 months; number of subjects enrollment, range of 36 to 518 subjects; number of sites utilized, range of 4 to 74 sites; and enrollment rate, range of 0.11 to 4.04 subjects/sites per month. There were 17 indications with ≥30 multicenter trials, which allowed for enrollment metric calculation by trial phase. CONCLUSIONS This study provides sponsors with an understanding of the number of subjects and sites needed to complete a trial while also setting realistic enrollment timelines. Although this work represents the US market, more work is needed to better understand other countries given that country-specific guidelines and subject beliefs may impact enrollment metrics.