First oral therapy for pulmonary arterial hypertension approved by FDA

November 21, 2001

Wed, 21 Nov 2001 17:00:00

Allschwil, Switzerland - The FDA has approved the endothelin antagonist bosentan (Tracleer® - Actelion) for the treatment of pulmonary arterial hypertension (PAH). This is the first oral therapy to be cleared for use in this indication and it is expected to be available to patients in the US from early December 2001.

In August 2001 the FDA's Cardiovascular and Renal Drugs Advisory Committee unanimously recommended approval of bosentan for this use based on the results of two pivotal trials, and in September, the FDA issued an approvable letter for the product. The letter stated that bosentan would be approved once the label had been finalized and appropriate patient monitoring measures were in place regarding liver enzymes and pregnancy prevention (there were concerns about these issues at the advisory committee meeting).

Actelion spokesperson Roland Haefeli told heartwire that, for those taking bosentan, two extra tests will be required on the blood samples which are already required every month in these patients. The extra tests will be liver enzyme function tests, because the drug has been associated with hepatoxicity in as many as 11% of patients, and a pregnancy check, because bosentan has shown evidence of teratogenicity in animals.

Two doses of bosentan are available - 62.5 mg and 125 mg - with the recommended daily dose being 125 mg taken twice a day. It is indicated specifically to improve exercise ability and decrease the rate of clinical worsening in PAH patients with significant limitation of physical activity (WHO Class III and IV). Bosentan is also awaiting approval for PAH in the European Union, Canada, Switzerland, and Australia.

Closed distribution will ensure good monitoring

The drug may only be prescribed through the Tracleer Access Program, which ensures a closed distribution, Haefeli says. The cost of Tracleer therapy is $28500 per patient per year, and Actelion will provide reimbursement assistance and, if necessary, will shoulder the full treatment costs on a temporary basis to ensure that patients do not go untreated, he added. The cost of the current treatment for PAH, epoprostenol (Flolan® - GlaxoSmithKline), is around $50-60000 per patient per year, he noted, adding that this treatment is "cumbersome" because it requires patients to be fitted with a central line for IV infusion and carry around a portable pump which administers the drug.

Another potential treatment for PAH, treprostinol (Remodulin® - United Therapeutics Corp), is a prostacyclin analogue similar to epoprostenol, but administration is by continuous subcutaneous infusion using a pump, which is less invasive than the central line needed for IV infusion. The FDA's Cardiovascular and Renal Drugs Advisory Committee also recommended treprostinol for approval in August 2001, although the vote on this product was split 6-3.

Related links

1. [HeartWire > News; Aug 13, 2001]

2. [HeartWire > News; Sep 19, 2001]


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