Updated from 1:55 p.m. EDT

Shares of

La Jolla Pharmaceutical

(LJPC) - Get Report

were among the worst-performing health and pharmaceutical stocks Friday, tumbling more than 60% after the company said the Food and Drug Administration requested an additional trial for its Riquent drug.

The pharmaceutical company late Thursday said that its lupus drug was deemed "approvable" by the FDA, but only after completion of an additional double-blind study that demonstrates the clinical benefit of Riquent. The FDA, according to the company, said that an ongoing clinical trial initiated in August would "appear to satisfy this requirement." The company said that it would continue to work with the FDA to discuss its options in the development of Riquent. Shares traded down $1.67 to $1.09.

Stryker

(SYK) - Get Report

fell 4.2% after the company posted third-quarter financial results that matched analysts' expectations. Excluding an acquisition-related charge, the medical device maker earned 33 cents a share on sales of $1.03 billion. Looking ahead, the company raised its 2004 earnings estimates by a penny, to $1.43 a share. For 2005, Stryker expects earnings growth of at least 20%, implying earnings of at least $1.72 a share. Analysts polled by Thomson First Call are expecting 2005 earnings of $1.71 a share. Shares traded down $1.84 to $42.09.

Shares of

Given Imaging

(GIVN)

fell 11.8% after the company posted preliminary third-quarter sales that fell short of expectations. The medical device maker said that it expects sales of more than $14.5 million during the quarter. Analysts had been expecting sales of $15.1 million. The company plans to release its full third-quarter results on Oct. 28. Shares traded down $5.18 to $38.90.

Possis Medical

( POSS) fell 33.6% after the medical device maker lowered its first-quarter earnings and sales guidance. The company now expects earnings of 10 cents to 11 cents a share, down from its previous guidance of 11 cents to 13 cents a share, on sales of $17.5 million, which is down from previous guidance of $19 million to $19.5 million. Analysts had been expecting earnings of 13 cents a share on sales of $19.3 million. Shares traded down $4.95 to $9.78.

Other health care volume movers included

Pfizer

(PFE) - Get Report

, down 58 cents to $28.50;

Merck

(MRK) - Get Report

, up 31 cents to $30.50;

Schering-Plough

( SGP), down 8 cents to $17.16;

Amgen

(AMGN) - Get Report

, up $1.22 to $55.22; and

Genentech

( DNA), up $1.21 to $48.26.SE" PRIMARY="NO"/>, down 17 cents to $17.24.