Abstract
Purpose:
Limited information exists on the degree to which cataract formation impacts the drug development process of compounds across a number of therapeutic areas. As such, we conducted a systematic literature search on cataract formation as an adverse event in the overall drug development process and developed an economic model to estimate its impact.
Methods:
A systematic literature search was conducted using Google scholar, which incorporates a number of literature database search engines. The key search criteria used were the terms "phase I trial" cataract. The word trial was replaced with study and clinical and the phase was varied from pre-clinical to phase I,II,III, and IV, respectively. The economic model was developed in Visual Basic for Applications (VBA). The key input parameters included: the number of patients in each of the clinical phases, the probability of the trial phase being successful, the costs of treating cataract, the cost of other adverse events and the length of time spent in each of the various phases. Costs were discounted over the length of the trial using a discount rate of 5%.
Results:
Data from the systematic review indicated that in those cases where cataract occurred in drugs for a life-threatening condition, it did not impede the trial and the costs of treating cataract were out-weighed by those costs attributable to the life-threatening condition of interest. The economic model forecasted that the mean break even time for a drug with possible cataractogenic adverse events in the drug development process ranged from a low of 1.26 years to a high of 6.36 years assuming that the drug would be marketed to a patient population of 100,000 at a cost of US$ 25 per unit. Such break even measures may facilitate the comparison between the costs and adverse events in the selection of potential compounds for development.
Conclusions:
Our model provides an understanding of the relative costs of cataract in the context of drug trials over a range of life-threatening, non-life-threating and sight-threatening indications. Such information is of particular value to a wide audience of industrial R & D organizations, clinical trial scientists, clinicians and healthcare funding administrators. Utilization of the model may help to guide and refine the drug development process and improve candidate selection.