Ventana Medical Systems has responded in the negative yet again to a fourth extension of Roche's $3 billion takeover bid and expressed annoyance at the Swiss major's “futile” tactics.

Roche has extended for the fourth time its unsolicited tender offer to acquire Ventana, the world’s leading tissue-based cancer diagnostics firm, from November 1 to January 17 next year. The Basel-based firm is offering to $75.00 per share in cash but the US group is deeply unimpressed.

Chief executive Christopher Gleeson said that “more than 99.5% of our investors have now essentially turned down Roche’s inadequate offer four times, and yet Roche persists with its futile and costly tactics”. He added that “virtually all of our investors agree with us that $75.00 is a non-starter and they recognise that we are gaining real momentum in our marketplace”.

Mr Gleeson continued by saying that the board continues to recommend that shareholders not tender any of their shares to Roche and “reinforces its commitment to providing superior value by continuing to successfully execute on its strategic plan and capitalise on the many opportunities ahead.” He praised the firm’s staff “who are continuing to perform extremely well despite the potential for distraction, and we are grateful to our shareholders for their continued support”. Less than 0.2% of Ventana’s 35 million outstanding shares were tendered into the Roche offer after the third extension.

FDA warns that CellCept may cause birth defects
The latest Ventana response followed an announcement by the US Food and Drug Administration which said that it had added a new warning to the label on the firm’s CellCept (mycophenolate mofetil) stating that the organ transplant drug may increase the risk of miscarriage or birth defects.

The agency and Roche noted that the drug has been associated with increased pregnancy loss and congenital malformations and has been changed to Category D (positive evidence of foetal risk) from Category C (risk of foetal harm cannot be ruled out). The agency issued the warning on CellCept, which posted sales last year of 1.84 billion Swiss francs, ($1.58 billion).

The label change is the result of data from the US National Transplantation Pregnancy Registry, which showed that 24 patients reported 33 pregnancies exposed to CellCept-containing regimens which led to 15 miscarriages and 18 live-born infants. Postmarketing data taken from 1995 to 2007 revealed 25 spontaneous abortions among 77 women exposed to the drug during pregnancy and 14 had deformed babies, six of whom suffered ear defects.

Because such data is reported voluntarily to the FDA, “it is not always possible to reliably estimate the frequency of particular adverse outcomes”, Roche said, though it acknowledged that similar defects had been found in preclinical animal studies.

The FDA concluded by warning that CellCept should not be given until a negative pregnancy test is confirmed within one week prior to therapy. Women prescribed the drug must also receive birth control counselling and use effective contraception, it said.