The first step in the clinical development of PHMB is a so-called phase I trial, in which three different concentrations of PHMB and placebo eye-drops are tested in healthy volunteers. The main purpose of this trial is to determine whether PHMB is safe, and what is the highest tolerable dose in healthy volunteers. This phase I trial, which started in September 2015, is held at three clinical centres in the Netherlands and Belgium, and aims to enrol 90 volunteers. The healthy volunteers are screened (to ensure that they meet all the criteria for the trial) and will use the study medication (PHMB or placebo eye drops) during two weeks. They will visit the clinical centre several times in order to check whether the eye drops have any effect on their eyes or on routine blood tests. The subjects will also be asked to report any possible side effects of the eye drops.
Once the phase I trial has been completed successfully, a larger phase III study in patients will follow. This trial, which will take place at various eye hospitals in Europe, starting sometime in 2016. The purpose of this trial will be to show that PHMB is effective and safe for the treatment of Acanthamoeba keratitis.