What is Cystadrops - Mercaptamine used for?
Cystadrops is an ophthalmic (eye) medicine used in patients from 2 years of age with cystinosis. Cystinosis is a hereditary disease characterized by the accumulation in the body of a natural substance called cystine, which causes the formation of harmful crystals particularly in the kidneys and cornea (the transparent membrane that constitutes the anterior portion of the eye). Cystadrops is used to reduce the accumulation of cystine crystals in the cornea.
Because the number of cystinosis patients 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 ingredient mercaptamine (also known as cysteamine)
How is Cystadrops - Mercaptamine used?
Cystadrops can only be obtained with a prescription. Treatment should be initiated under the supervision of a physician experienced in the treatment of cystinosis.
Cystadrops is available in the form of eye drops. The recommended dose is 1 drop in each eye 4 times a day during waking hours. The dose can be progressively decreased by the doctor up to 1 drop per day based on the results of ophthalmological examinations. Treatment should not be interrupted for a long time.
For more information, see the package leaflet
How does Cystadrops - Mercaptamine work?
Damage resulting from the accumulation of cystine crystals in the corneal cells can cause serious visual problems. The active ingredient in Cystadrops, mercaptamine, reacts with cystine, dissolving it and forming substances that can be eliminated from the cells. When applied to the eye, the amount of cystine present in corneal cells is reduced and eye damage is limited.
What benefit has Cystadrops - Mercaptamine shown during the studies?
Cystadrops was compared with another less concentrated mercaptamine eye drop solution in a main study of 32 patients from 2 years of age with cystinosis. The main measure of effectiveness was based on the reduction of corneal cystine crystals observed under the microscope and quantified with a score called IVCM between 0 and 28 (where 0 corresponded to the absence of crystals). At the start of the study, patients in both groups had an average score of 10.
Cystadrops was more effective than the comparator medicine in reducing corneal crystals of cystine after 3 months of therapy: in patients treated with Cystadrops the IVCM score was decreased by 4.6 points, while in those treated with the comparator medicine it was reduced of 0.5 points. Cystadrops therapy also helped reduce photophobia (a feeling of discomfort in the eye associated with exposure to bright light).
What are the risks associated with Cystadrops - Mercaptamine?
The most common side effects with Cystadrops (which may affect more than 1 in 10 people) are affecting the eye and include pain, itching and eye irritation, increased tearing, blurred vision and hyperaemia (redness) in the eye. These effects are usually mild or moderate in intensity and are not lasting.
For the full list of restrictions and side effects reported with Cystadrops, see the package leaflet
Why has Cystadrops - Mercaptamine been approved?
Mercaptamine-based eye drops produced locally at pharmacies or hospitals have been used for many years to treat the ocular symptoms of cystinosis. Furthermore, one study showed that Cystadrops is effective in reducing corneal cystine crystals. The medicine has also improved other symptoms of cystinosis such as photophobia. Regarding safety, the undesirable effects on the eye, although very frequent, are usually manageable.
The Agency's Committee for Medicinal Products for Human Use (CHMP) decided that Cystadrops' benefits are greater than its risks and recommended that it be approved for use in the EU.
What measures are being taken to ensure the safe and effective use of Cystadrops - Mercaptamine?
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.
More information about Cystadrops - Mercaptamine
For the full EPAR for Cystadrops, see the Agency's website: ema.europa.eu/Find medicine / Human medicines / European public assessment reports. For more information about Cystadrops therapy, 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 related to Cystadrops is available on the Agency's website: ema.europa.eu/Find medicine / Human medicines / Rare disease designation.
