Elan has announced the price it will charge for Tysabri, the multiple sclerosis drug whose return to market was sanctioned by US regulators earlier this week.

The company, which will distribute the drug developed in conjunction with US biotech group Biogen Idec, said it was raising the wholesale acquisition cost of the drug to $2,184.62 (€1,728.27) per vial, up 21 per cent on its original launch price.

The company also confirmed that the drug was expected to be available to patients next month following "completion of key activities related to the risk management plan".

"Based on a treatment plan of once every four weeks (13 times per year), we calculate the cost per annum to be $28,400," Goodbody Stockbrokers' analyst Ian Hunter said yesterday.

"This is $4,900 [ 21 per cent] ahead of the $23,500 we have built into our numbers. This increase gives us further comfort in our numbers and we believe will act as a support to the share price at current levels."

Elan said the drug had originally been priced in November 2004 when it was first approved by the US authorities. The breakthrough treatment was suspended just four months later when it was linked to a rare but potentially fatal brain disease, progressive multifocal leukoencephalopathy (PML).

"The original price was set quite some time ago and, in the intervening period, our competitor products have increased in price by between 10 and 27 per cent," a spokeswoman for the company said.

She also noted that additional data now available had shown the product was even more efficacious than originally thought in treating MS.

Tysabri, on which European drug regulators are due to decide in the next month or so, is the second prescription drug to be allowed back on the US market after being suspended for safety reasons.

Davy Stockbrokers' analyst Jack Gorman said the new price also took into account "the additional costs associated with the risk map".