Health stocks followed the broader market volatility Friday as the House approved an economic bailout plan and President Bush pledged to sign it.

The Nasdaq and Amex biotechnology indices were up 1.3% and 0.8%, respectively, by midafternoon Friday. The Amex pharmaceutical index settled into a 0.3% gain.

Amgen ( AMGN) said late Thursday that the U.S. District Court in Boston upheld the prior jury verdict and court rulings on its dispute with Roche regarding patents related to its anemia drugs Aranesp and Epogen. The court also ruled that Amgen is entitled to permanent injunction prohibiting Roche from selling Mircera in the U.S.

Rodman and Renshaw analysts called the court's ruling significantly positive for Amgen. Shares were up by $1.68, or 2.9%, at $60.27.

Meanwhile, Genentech ( DNA) said Thursday after the close that it issued a "Dear Healthcare Provider" letter to tell prescribers about a case of progressive multifocal leukoencephalopathy (PML) in a patient who'd taken Raptiva for chronic plaque psoriasis. The company said that based on medical information to date, Raptiva may have contributed to the development of this deadly brain infection in the recent case. The company said one other patient, age 62, treated with the drug developed progressive neurological symptoms and died of an unknown cause.

Genentech said it would work with the Food and Drug Administration (FDA) to update the prescribing information for the drug and determine whether further action would be necessary. Shares were up $2.23, or 2.6%, at $88.74.

A number of drugs have been linked to PML, including Biogen ( BIIB) and Elan's ( ELN) Tysabri, Biogen and Genentech's Rituxan, Roche's CellCept and Novartis' ( NVS) Myfortic.

Cowen and Co. analyst Eric Schmidt, who reaffirmed his neutral rating for Biogen on Friday, wrote in a note to investors that a recent panel of physicians were optimistic about Biogen's multiple sclerosis drugs Tysabri and Avonex, according to The Associated Press. Shares fell earlier in the year on speculation about how two confirmed cases of PML in patients taking Tysabri would affect sales. Shares were up $1.89, or 3.8%, at $51.57 on Friday.

A small-cap stock, Micromet ( MITI) said Friday that it closed a $40 million private placement financing, which was announced Sept. 30. Proceeds will go to advance and broaden the company's antibody programs. Shares were up 40 cents, or 9.5%, at $4.61 on unusually low volume.

In analyst actions, Leerink Swann dropped its price target for Amylin ( AMLN) to $34 from $47, with an outperform rating. Shares were up 17 cents, or 0.9%, at $18.86.

UBS picked up coverage on Mentor ( MNT) with a neutral rating. Shares were off by 31 cents, or 1.4%, at $22.49.