Roche Holding AG, the world's biggest maker of cancer drugs, said the takeover price of $112 a share sought by partner Genentech Inc.'s independent directors isn't based on ''realistic assumptions.''

Roche raised its offer on 6 March to buy the 44 per cent of the South San Francisco-based company it doesn't already own to $93 a share, or $45.7 billion. Roche's hostile bid last month of $86.50 a share ''substantially undervalues'' the company, Genentech said. (See: Roche raises Genentech offer from $86.50 to $93 a share / Genentech rejects Roche's $43.7-billion takeover offer as too low)

''We feel that the price proposed by the special committee -  $112 per share - is not based on realistic assumptions about the future,'' chairman Franz Humer said in a copy of a speech distributed today at its annual general meeting in Basel, Switzerland.

Full ownership of Genentech would give Roche rights to the biotech company's portfolio of lucrative cancer drugs and other medicines, including Avastin, which is approved to treat advanced colon, breast and lung cancers and is being tested for several other uses.

Late yesterday, The Wall Street Journal reported on its web site that Genentech is near a deal to sell itself to Roche for $95 a share, or $46.7 billion. Citing unnamed people familiar with the matter, the Journal reported that the companies were at odds over "timing and closing conditions," and that the deal could still fall apart. However, there has been no official comment from either side. (See: Roche raises Genentech offer from $86.50 to $93 a share) 

The news came on the same day as another massive deal in the pharmaceutical / biotechnology space. Drug giant Merck announced plans to merge with rival Schering-Plough in a deal worth $41.1 billion. (See: Merck to acquire Schering- Plough for $41 billion)

Genentech said in a US Securities and Exchange Commission filing Tuesday that it had 466,159,047 shares outstanding - excluding those owned by Roche, directors, officers and others - and believed that minority shareholders would have to tender at least 233,079,524 shares for Roche to get a majority of those shareholders.

If Roche owns 90 per cent of more of the outstanding shares when the deal is consummated, it would make an immediate cash payment equal to the price per share paid in the offer and a future cash payment based on a valuation, according to a squeeze-out provision in another SEC filing last month.

Best known for its cancer-fighting therapies Herceptin and Avastin, Genentech is one of the world's largest and oldest biotechnology firms, with a market capitalization of about $95 billion. Roche is Genentech's largest shareholder and currently own 55.8 per cent of the biotech.

Of Genentech's seven board members, three are independent directors, one is the Genentech chief executive and the three others are designated by Roche. Genentech CEO Arthur Levinson pointed out at a recent conference in New York that Genentech-developed products accounted for 66 per cent of Roche's top-selling drugs in 2008.