Treatment of Acanthamoeba keratitis with high dose PHMB (0.08%) monotherapy in clinical practice: A case series

Objectives Acanthamoeba keratitis (AK) is a rare sight-threatening infectious disease with no approved pharmacological treatments. Topical polihexanide 0.8 mg/ml (PHMB 0.08%) completed a pivotal clinical trial showing a medical cure rate of 84.9%. The purpose of this study is to evaluate the efficacy and safety of PHMB 0.08%, given as monotherapy, in clinical practice.Methods consecutive cases of AK were included. Diagnosis was confirmed by in vivo confocal microscopy or PCR. Patients were treated with PHMB 0.08% as part of a name-based compassionate use program. Treatment delivery frequency and termination were as advised in the pivotal clinical trial. Medical cure was defined as clinical evidence of healed epithelium and absence of corneal inflammation lasting 3 months after discontinuing all treatments.Results twelve eyes of 11 contact lens wearers with AK of variable severity were evaluated. Eleven of 12 (91.7%) eyes achieved a medical cure with no surgery. One eye had a corneal perforation and required emergency therapeutic keratoplasty. The median time of treatment with PHMB 0.08% was 100 days (range 35-222). Seven eyes (58.3%) reached a final visual acuity of 20/50 Snellen or better. Two subject reported worsening of conjunctival hyperaemia during the intensive phase of the treatment. No other adverse drug reactions were observed.Conclusion topical treatment with PHMB 0.08% monotherapy successfully cured AK in 11 of 12 eyes when used in real-world clinical practice, thereby confirming that results observed in the clinical trial could be obtained in this setting.