Shares in pharmaceutical group Elan continued their plunge yesterday, falling to their lowest level for a year as investors continued to downgrade the stock. On the Nasdaq index, the shares fell $6 in early trading to a year-low of $59 (€55.16) and, at the close, were down $5 on $60.

While the president of Elan's pharmaceutical technologies division, Mr Seamas Mulligan, told NCB's Irish equity conference yesterday that the recent share-price fall was part of a "general weakness" in the sector, analysts believe the group has more fundamental problems to address if it is restore its reputation among investors.

The main factor in the recent weakness is the delay in filing a new drug application with the US Food & Drug Administration for its ziconotide pain-killing drug.

The scale of the selling has taken analysts aback - almost one million shares were sold in a single deal through Donaldson Lufkin & Jenrette on Thursday night and more heavy selling continued yesterday. Analysts said there was little sign as yet of Elan finding a support level, and the shares may have to fall further before buyers return.

A presentation to US investors this week was poorly received and failed to stem the selling. Another factor that has hit Elan shares was an unconfirmed report that American financial magazine Barrons will publish a negative report on the company in its next issue.

Elan's fall in the past six weeks has been staggering, with the share trading down from $87.75 in mid-March to $59 at its lowest level yesterday, knocking almost one-third off Elan's stock market value.

Elan said earlier this week that it would be the fourth quarter of the year before it makes its new drug application to the FDA for ziconotide. Analysts had been expecting a much tighter time-frame for a drug that is expected to be one of the company's key new products.