NEW YORK – Biotechnology giant Genentech is turning down a buyout offer from its majority owner Roche, saying the $43.7 billion takeover bid undervalues the company.

Genentech says it would consider a better offer.

South San Francisco, Calif.-based Genentech says the special committee formed in response to the offer unanimously rejects the bid. It breaks down to $89 per share, or a 8.8 percent premium to the closing price on July 18, the last trading day before the offer was announced. Genentech shares rose 33 cents to $98.18 in morning trading.

Switzerland-based Roche already owns 55.9 percent of the Genentech, which gets most of its revenue from cancer drugs, including the blockbuster treatment Avastin.