Cystadrops

Cystadrops is an eye medicine used in patients from 2 years of age who have cystinosis. Cystinosis is an inherited disease where a natural substance called cystine builds up in the body forming damaging crystals, particularly in the kidneys and cornea (the transparent layer in front of the eye). Cystadrops is used to reduce the build-up of cystine crystals in the cornea.

Because the number of patients with cystinosis is low, the disease is considered ‘rare’, and Cystadrops was designated an ‘orphan medicine’ (a medicine used in rare diseases) on 7 November 2008.

Cystadrops contains the active substance mercaptamine (also known as cysteamine).

Cystadrops can only be obtained with a prescription and treatment should be started under the supervision of a doctor experienced in the management of cystinosis.

Cystadrops is available as eye drops. The recommended dose is 1 drop in each eye 4 times a day during waking hours. The doctor may decrease the dose progressively to 1 drop a day depending on the results of eye examinations. Treatment should be continued long-term.

For further information, see the package leaflet.

Damage from the build-up of cystine crystals inside the cells of the cornea can cause serious vision problems. The active substance in Cystadrops, mercaptamine, reacts with cystine to dissolve it and to form substances that can be removed from the cells. When it is applied to the eye, the amount of cystine in the cells of the cornea decreases, limiting damage to the eye.

Cystadrops has been compared with another less concentrated mercaptamine eye drop solution in one main study involving 32 patients from 2 years of age with cystinosis. The main measure of effectiveness was based on the reduction in corneal cystine crystals as seen under the microscope and quantified using a score called the IVCM score. The score ranges from 0 to 28, with 0 corresponding to no crystals. At the start of the study patients in both groups had an average score of 10.

Cystadrops was shown to be more effective than the comparator at decreasing corneal cystine crystals after 3 months of treatment: in patients using Cystadrops the IVCM score decreased by 4.6 points compared with a decrease of 0.5 points in patients using the comparator. Treatment with Cystadrops also led to reductions in photophobia (eye discomfort in bright light).

The most common side effects with Cystadrops (which may affect more than 1 in 10 people) are related to the eye and include pain, itching and irritation in the eye, increased lacrimation (watering eyes), blurred vision and ocular hyperaemia (red eye). These effects are usually mild or moderate and do not last.

For the full list of all side effects and restrictions with Cystadrops, see the package leaflet.

Mercaptamine eye drop solutions made up locally in pharmacies or hospitals have been used for many years for the management of eye symptoms of cystinosis. In addition, Cystadrops has been shown in a study to be effective at decreasing corneal cystine crystals. The medicine also improved other symptoms of cystinosis such as photophobia. Regarding safety, although side effects related to the eye are very common, they are usually manageable.

The Agency’s Committee for Medicinal Products for Human Use (CHMP) decided that Cystadrops’s benefits are greater than its risks and recommended that it be approved for use in the EU.

Recommendations and precautions to be followed by healthcare professionals and patients for the safe and effective use of Cystadrops have been included in the summary of product characteristics and the package leaflet.

The European Commission granted a marketing authorisation valid throughout the European Union for Cystadrops on 19 January 2017.

For more information about treatment with Cystadrops, read the package leaflet (also part of the EPAR) or contact your doctor or pharmacist.

The summary of the opinion of the Committee for Orphan Medicinal Products for Cystadrops can be found on the Agency’s website.