A few acquisitions shook biotech stocks on Tuesday, while others traded on regulatory news and clinical discussions.

Japanese company

Shionogi & Co.

said it plans to buy the remaining outstanding shares of

Sciele Pharma

( SCRX) in an all cash tender offer of $31 a share, a 57% premium to the stock's closing price Friday. The deal has a total equity purchase price of roughly $1.1 billion, valuing the company at approximately $1.4 billion, and is expected to close in the fourth quarter. Sciele shares rose $11.40, or 59.2%, to $30.67.

Novacea

(NOVC)

shares declined 57 cents, or 24.3% to $1.78 after the company said it would be acquired by privately owned

Transcept

in an all-stock transaction. Novacea shareholders will own 40% of the new, combined company, which will be named Transcept Pharmaceuticals and is expected to be listed on Nasdaq under a different ticker symbol. The deal is expected to close during the fourth quarter of 2008 or the first quarter of 2009.

Introgen

(INGN) - Get Report

dropped 38.7% on Tuesday after the company said the Fodd and Drug Administration

deemed incomplete

its application for cancer-drug hopeful Advexin. Shares fell 36 cents to 57 cents.

In clinical news, full results of the SEAS trial on Vytorin were published in the

New England Journal of Medicine

on Tuesday, as were two other items with regard to the highly debated cholesterol drug. Researchers at Oxford University looked at the SEAS trial and two large ongoing studies, and said the higher rate of cancer in the SEAS trial was likely complete chance. However, in the same issue

experts sounded

a note of caution in an editorial.

Merck

(MRK) - Get Report

and

Schering-Plough

( SGP) fell by 2.4% and 1.6%, respectively. But the stocks didn't hurt the Amex pharmaceutical index which rose 0.5% despite a lesser performance by its peer biotech indices.

Abbott Laboratories

(ABT) - Get Report

was the best performer in the pharma index, gaining $1.58, or 2.8%, to $59.01.