Parasitic Ulcer Treatment Trial

PROJECT SUMMARY Introduction. Acanthamoeba keratitis is a blinding corneal infection with few treatment options. Corticosteroids are currently used by many cornea specialists for acanthamoeba keratitis, but their use is controversial given their ability to promote acanthamoeba growth. Trial Design. This proposed study is a randomized trial assessing whether topical corticosteroids improve clinical and visual outcomes. • Inclusion. 200 patients with microbiologic evidence of acanthamoeba keratitis (i.e., on culture, smear, or polymerase chain reaction) from 11 centers in the United States, United Kingdom, Brazil, and India will be eligible if there is evidence of ocular inflammation after 4 weeks of anti-amoebic therapy. • Pre-trial intervention. All participants will be treated with a standard of care anti-amoebic treatment, with the preferred treatment being polyhexamethylene biguanide (PHMB) 0.02% eyedrops. • Trial intervention. After the fourth week of anti-amoebic treatment, if there is ocular inflammation (i.e., corneal, episcleral, or anterior chamber inflammation) then participants will be offered enrollment and randomized to either topical prednisolone sodium phosphate 1% or placebo eyedrops. Participants will continue PHMB therapy while on the study medications. • Trial outcomes. The primary outcome is best corrected visual acuity with a hard contact lens, assessed at months 6 and 7. Secondary outcomes include (i) time to clinical resolution, (ii) time to perforation or therapeutic corneal transplantation, (iii) corneal thinning, (iv) eye pain, and (v) quality of life. Secondary objectives. Corneal swabs will be collected at the time of the initial diagnosis and processed with metagenomic deep sequencing to determine if endosymbiotic bacteria living within the amoeba, or the organism’s gene expression profile, is predictive of severe inflammation. Conjunctival swabs will be collected prior to randomization to determine if the host gene expression profile is predictive of severe inflammation. Impact. The trial will provide much-needed evidence using the highest-quality study design: a randomized controlled trial. Moreover, this will be the largest prospective cohort of acanthamoeba keratitis to date, with extensive microbiological, clinical, and imaging data from enrollment centers on 4 continents, which will allow numerous secondary analyses. The study results will be directly useful for providers who treat acanthamoeba keratitis as well as the patients currently affected by this blinding infection.