New liver damage info added to Actelion drug label

Last Updated: 2006-03-02 14:00:29 -0400 (Reuters Health)

WASHINGTON (Reuters) - New information about rare cases of liver damage has been added to the label of Actelion's Tracleer lung drug, U.S. regulators and the Swiss biotechnology company said on Thursday.

The Swiss company relies heavily on Tracleer to sustain growth but analysts worry that the medicine -- currently indicated to treat a rare form of lung disease known as pulmonary arterial hypertension (PAH) -- faces increasing competition.

"The notification underscored the need to continue monthly liver function monitoring for the duration of Tracleer treatment and the need to adhere to the recommended dosage adjustment and monitoring guidelines," a statement on the Food and Drug Administration Web site said.

In a letter to prescribers, dated March 1 and published on the FDA's site, Actelion reiterated the importance of testing patients on Tracleer for liver function after rare cases of raised liver enzymes -- an indication of possible liver malfunction -- were observed.

"This highlights the fact that you have to adhere to the label as it was written four years ago," said Roland Haefeli, a spokesman for Actelion. "You have to take action in case of elevated liver enzyme."

Shares in Actelion were 0.3 percent lower at 114 Swiss francs by 1526 GMT.

The letter mentions one case to illustrate what prescribers need to look for. Actelion said only rare cases of elevated liver enzyme had been observed in patients using Tracleer.

"This patient developed liver enzyme elevation slowly over time and went into liver failure, from which the patient recovered," Haefeli said.

In addition to Pfizer's Revatio, which contains the same active ingredient as Viagra, Tracleer could be challenged by another U.S. firm, Encysive, which says its Thelin drug has a superior safety profile to Tracleer.

In clinical tests, some 3 percent of patients on Thelin had raised liver enzyme levels, Encysive has said, against 11 percent of those on Tracleer.

Myogen Inc is also developing a PAH drug called ambrisentan.

(Reporting by Lisa Richwine in Washington and Tom Armitage in Zurich)