Pharma stocks mostly fell while their biotech counterparts generally kept in the green midweek, presenting a mixed platter of regulatory and business updates Wednesday.

Indevus ( IDEV) shares slid 69% to $1.26 Wednesday on news of a Food and Drug Administration delay. The company said regulators will not approve Nebido, a long-acting injectable testosterone, without additional safety data and a new clinical trial expected to take 18 months.

The FDA also said Wednesday that it's looking into a possible cancer risk in a class of drugs called tumor necrosis factor blockers (TNF inhibitors) in young arthritis patients. The drugs include Abbott's ( ABT) Humira, Schering-Plough's ( SGP) Remicade and Amgen ( AMGN) and Wyeth's ( WYE) Enbrel.

The agency issued an "early communication" that it has received 30 reports of cancer development in children and young adults who were taking the drugs over the last 10 years. About half were lymphomas, or immune system cancer.

Amgen and Wyeth, which issued a statement in response, traded up 0.8% and down 0.9%, respectively. Abbott's shares were down 0.5%, and Schering fell 0.4%.

In ratings actions, Cowen and Co. analyst Steve Scala upgraded Eli Lilly ( LLY) to outperform from neutral on Wednesday, on optimism regarding the upcoming FDA decision on Lilly's blood-thinner Effient. Lilly's shares added 1.5% to $49.04.

Scala also upgraded Novartis ( NVS) to outperform from neutral, but downgraded Bristol-Myers Squibb ( BMY) to neutral from outperform. Those pharma stocks each traded down 1.4%.

The Amex pharmaceutical index, which includes Lilly and Bristol but not Novartis, was down 0.6% at 296.86. Biotechnology companies seemed to fare better. The Nasdaq and Amex biotech indices both added 0.9%.

A component of the Nasdaq index, diagnostics company Sequenom ( SQNM), surged 21.8% to $9.33 after announcing that its SEQureDX, a prenatal screening test for maternal blood for Down Syndrome, was effective in all samples (200 were tested) without any false positives. The results were superior to current serum-testing options, which have detection rates between 70% to 90% and false-positive rates as high as 5%.

Sequenom plans to initiate a multisite validation study, which will include several thousand samples, in the fourth quarter this year and to launch the test in the U.S. in the first half 2009. The company said it plans to transfer the technology to its laboratory partners at the end of this year.

Elsewhere, shares of Datascope ( DSCP) leapt 11.5% to $46.60 on news that the medical device company is looking at a possible sale. The company said its financial adviser Lehman Brother received "a number of expressions of interest from third parties seeking to pursue a possible acquisition" of Datascope after the company sold its patient monitoring business. Datascope also offered financial guidance, saying it expects revenue from continuing operations to show year-over-year growth of 6%-7% in the fiscal fourth quarter and growth of 7%-9% for fiscal 2009, which amounts to about $250 million to $254 million.