Thelin - sitaxentan sodium

PLEASE NOTE: MEDICINAL PRODUCT NO LONGER AUTHORIZED (severe hepatic side effects)

What is Thelin?

Thelin comes in the form of yellow-orange, capsule-shaped film-coated tablets containing 100 mg of the active substance sitaxentan sodium.

What is Thelin used for?

Thelin is used to treat adult patients with class III pulmonary arterial hypertension to improve their ability to exercise. Pulmonary arterial hypertension is a disease in which the patient has abnormally high pressure in the pulmonary arteries; class III ("moderate") indicates the severity of the disease. Thelin has been shown to be effective in primary pulmonary hypertension (no other cause). ) and in pulmonary hypertension caused by a connective tissue disease.
Because the number of patients with pulmonary hypertension is low and the disease is rare, Thelin was designated an 'orphan medicine' (a medicine used in rare diseases) on 21 October 2004.
The medicine can only be obtained with a prescription.

How is Thelin used?

Treatment with Thelin should only be started and monitored by a physician experienced in the treatment of pulmonary arterial hypertension. It is taken in doses of 100 mg (one tablet) daily, with or without food, preferably at the same time each day and the dose not must exceed one tablet a day. It must not be taken by patients who have or have had severe liver problems. If, after 12 weeks, the patient's condition worsens, the doctor should review the treatment.

How does Thelin work?

Pulmonary arterial hypertension is a debilitating disease in which there is severe constriction (narrowing) of the blood vessels in the lungs, which causes very high pressure in the vessels that carry blood from the right side of the heart to the lungs. The active substance in Thelin. , sitaxentan sodium, is an antagonist of a naturally occurring substance called endothelin-1 (ET-1), which causes severe constriction of blood vessels. By blocking the effect of endoltelin, it reduces the constriction of blood vessels and this facilitates the decrease in blood pressure.

How has Thelin been studied?

Before being studied in humans, the safety and efficacy of the drug were tested in experimental models.
Three main studies were performed, involving 523 patients. Doses of 50, 100 and 300 mg of sitaxentan sodium were compared with placebo (a dummy treatment). Effectiveness was studied by measuring the distance patients could walk for 6 minutes after 12 weeks of treatment.

What benefit has Thelin shown during the studies?

After treatment with Thelin, patients were able to walk a significantly greater distance. Before treatment with 100mg of sitaxentan sodium, the average walking distance was between 343 and 394 meters, with an increase of about 33 meters after treatment. While it's not a big increase, it's a significant improvement. Studies have shown that doses of 50 mg did not cause significant benefit and that doses of 300 mg showed no better benefit than the 100 mg dose.

What are the risks associated with Thelin?

The most frequently reported side effect (occurring in more than 1 in 10 patients) was headache. Other common side effects (between 1 and 10 in 100 patients) were peripheral edema (swelling of the arms and legs). ) and nasal congestion (stuffy nose). For the full list of side effects reported with Thelin, see the package leaflet.
Thelin must not be used in people who may be hypersensitive (allergic) to sitaxentan sodium or other ingredients, people with severe liver problems or high levels of certain liver enzymes. The patient's liver function should be monitored before and during treatment. Thelin must not be taken with cyclosporine A (a medicine used to treat psoriasis and rheumatoid arthritis and to prevent rejection in the event of a liver or kidney transplant) and care should be taken when taken at the same time as warfarin (a medicine used for thin the blood).
Women taking Thelin must be careful not to get pregnant and use effective contraception. It is not known whether sitaxentan is excreted in milk or not or whether it may be harmful to a nursing infant. You are advised to avoid breastfeeding while taking Thelin.

Why has Thelin been approved?

The Committee for Medicinal Products for Human Use (CHMP) considers that Thelin has been shown to be effective and that this effectiveness is within the expectations for this class of medicines. It decided that the benefits of Thelin are greater than its risks for the treatment of adult patients with primary pulmonary arterial hypertension for improved physical capacity and pulmonary hypertension associated with connective tissue disease. The CHMP therefore recommended the granting of the "Marketing Authorization" for Thelin.

What measures are being taken to ensure the safe use of Thelin?

The company that makes Thelin will have to provide educational material to doctors and patients (Patient Information Card). The company will also set up a system for monitoring side effects, suspected interactions with other medicines and the outcome of any pregnancy that may occur in a woman taking the medicine.

Other information about Thelin:

On 10 August 2006, the European Commission granted Encysive (UK) Ltd a marketing authorization valid throughout the European Union.
For the summary of the opinion of the Committee for Orphan Medicinal Products for Thelin, click here.
For Thelin's full evaluation version (EPAR) click here.

Last update of this summary: 06-2006.

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