Cystadrops Eye Drops for the Management of Ocular Cystinosis in Patients Aged 6 Months to < 2 Years.

Introduction: Cystinosis is a multisystemic disease manifesting in the eyes initially as asymptomatic corneal cystine crystals and later with photophobia and serious visual impairment. Systemic effects of cystinosis arise from multiple cellular dysfunctions, causing early presymptomatic effects and progressive complications. Corneal crystals are observed across all layers of the cornea from infancy, and crystal accumulation during childhood is rapid. Early treatment is imperative, but in Europe, at the time of this study, no topical therapy was licensed for patients < 2 years of age.

Methods: This study was a paediatric investigation plan approved by the European Medicines Agency to assess the safety profile and efficacy of Cystadrops (cysteamine hydrochloride 0.55%) over a 90-day period in patients aged 6 to < 24 months. Five patients were monitored for adverse events throughout the study. Corneal crystal score, photophobia, and best corrected visual acuity were assessed in each patient at day 1 and day 90, where possible. Compliance to Cystadrops treatment was recorded.

Results: All primary endpoints were met. Any adverse events were mild and did not prevent treatment continuation. Corneal cystine crystal and photophobia scores declined or remained constant in all patients at a stage in life when an increase might be expected.

Conclusion: Although the rarity of the disease renders large studies on infants impracticable, there is no indication that the safety and efficacy profile of Cystadrops differs in patients above or below 2 years of age. The authors recommend treatment initiation as soon as corneal crystals are apparent.

Clinical Trial Registry: Clinical Trials No: 2018-002984-24.