The USA’s MedImmune says that it intends to remain independent despite pressure from one of its major shareholders who feels the firm should put itself up for sale.

MedImmune’s comments came in a regulatory filing as the firm’s board noted that it had received a letter from David Katz, president of Matrix Asset Advisors, “commenting on the company’s quarterly results and suggesting that MedImmune consider a strategic sale.”

Last week, MedImmune posted revenues of $529 million for the fourth quarter, up 7% but around $25 million lower than analyst consensus estimates. However the company also said that it was delaying the filing of Numax (motavizumab), its follow-on drug from the respiratory treatment Synagis (palivizumab) which had 2006 sales of $1.1 billion, and that delay might postpone the launch of the drug to after September 2009.

Mr Katz was unimpressed and the letter, his third in recent months, stated that “MedImmune senior management once again showed why a growing number of analysts and, we surmise, investors as well, are pressing for a sale of the company." He added that “the failure to deliver and then to adequately account for the shortfalls in the sales of Synagis, continued misses on the projected progress of the vaccine FluMist, the consistent inconsistency of handling expense and gains recognition, to name just a few, have all brought the company to a crisis of confidence."

In response, MedImmune said it “welcomes the views of all our shareholders and values their input” but "after careful review” it had “reaffirmed its conclusion that the best way for MedImmune to maximize value for its shareholders is to aggressively implement its business plan."

The firm also said that it had considered “the impact of the recent publication of a successful pivotal clinical trial with refrigerated FluMist” showing its superior efficacy over the flu shot in children under five years of age in the New England Journal of Medicine. Sales of FluMist for the 2006 fourth quarter increased 128% to $18 million.

It seems, therefore, that MedImmune’s board is fairly determined to preserve the status quo as far as the firm’s status is concerned, but observers have noticed that billionaire investor Carl Icahn now owns 2.8 million shares in the firm. This is the same Mr Icahn who won control of US biotechnology company ImClone Systems at the end of last year, having ousted the board and accused management of failing to make the most of the company's cancer drug Erbitux (cetuximab).