Shares of

Pozen

(POZN)

were among the worst-performing health-related stocks Friday, plummeting 57% after the Food and Drug Administration requested additional safety information for Trexima, a migraine headache treatment.

The FDA said Trexima, which is being developed by Pozen and

GlaxoSmithKline

(GSK) - Get Report

, is approvable but needs the additional safety information, which may require the companies to conduct new studies. "Pozen and GSK intend to request a meeting with the FDA as quickly as possible to discuss the approvable letter and determine the appropriate next steps to gain full approval," the companies said in a press release. Shares of Pozen were trading down $8.11 to $6, while shares of GlaxoSmithKline dropped 71 cents to $54.69.

Genelabs Technologies

( GNLB) rose 8% after the drugmaker said it should have enough cash to fund operations until the beginning of 2008. Including $12.5 million in payments from licensing partner

Novartis

(NVS) - Get Report

, Genelabs expects to have a mid-year cash level of about $15 million. "The recent collaboration provides us with additional needed cash and allows us to continue to move forward with our three separate hepatitis C virus drug discovery programs, two of which now have top-notch corporate partners," the company said.

Separately, Genelabs received notification from Nasdaq officials that it is out of compliance with the market's bid price regulations, which require a stock to not trade below $1 for 30 consecutive business days. Shares of the company had traded below $1 a share until June 2, the last trading day before Genelabs announced a collaboration agreement with Novartis. Since the announcement, shares have traded above the $1 threshold. The company has until Dec. 4 to regain full compliance, it said. In the meantime, the company is in the process of appealing an earlier Nasdaq compliance issue related to minimum shareholder equity and market capitalization requirements. Shares recently were up 15 cents to $2.02.

Shares of

NxStage Medical

(NXTM) - Get Report

rose 6% after the maker of kidney dialysis machines priced a follow-on offering of 5.6 million shares at $8.75 apiece, resulting in net proceeds of about $44.6 million. Of the 5.6 million shares being sold, 5.5 million are being offered by the company. The rest are being sold by stockholders. The company plans to use the proceeds to fund working capital and for general corporate purposes. Merrill Lynch and JP Morgan are leading the underwriting syndicate. Shares rose 51 cents to $9.55.

Hana Biosciences

( HNAB) shares advanced 2% after the biopharmaceutical company's brain tumor treatment Ropidoxuridine received orphan-drug status. "This designation not only underscores the need for improved therapies in malignant glioma, it also reiterates the company's development strategy in areas of unmet need," the company said. Shares were up 13 cents to $8.78.

Other health care volume movers included

Pfizer

(PFE) - Get Report

, down 35 cents to $23.51;

Elan

(ELN)

, up 44 cents to $15.74;

Johnson & Johnson

(JNJ) - Get Report

, down 7 cents to $61.49;

Merck

(MRK) - Get Report

, down 4 cents to $33.93;

Amgen

(AMGN) - Get Report

, down 54 cents to $67.87;

Boston Scientific

(BSX) - Get Report

, down 29 cents to $19.70;

Genentech

( DNA), up 82 cents to $79.51;

UnitedHealth Group

(UNH) - Get Report

, down 44 cents to $45.81;

Teva Pharmaceutical

(TEVA) - Get Report

, down 33 cents to $36.44; and

Bristol-Myers Squibb

(BMY) - Get Report

, down 14 cents to $25.11.