Thursday's Health Winners & Losers

Health indices were flat Thursday as clinical developments, regulatory approvals and earnings tugged stocks in both directions.

Gilead(GILD Quote) benefitted from the recommendation of a data and safety monitoring board that a subgroup of a rival's drug in an HIV treatment trial should be switched to Gilead's Truvada.

In an interim analysis of an ongoing study, the high viral load in a trial on GlaxoSmithKline's(GSK Quote) Epzicom vs. Truvada revealed more toxicity and lesser efficacy in the Epzicom arm.

Trial investigators will consult with patients with high viral load to determine if they should remain on Ziagen or switch, according to a spokewoman from GlaxoSmithKline.

"Once these data are disseminated widely, we believe many physicians might transfer their Epzicom patients to a Gilead-based regimen, such as Truvada," wrote Bear Stearns analyst Mark Schoenebaum in a note to investors.

Gilead's shares rose $1.67, or 3.8%, to $45.46. Glaxo's shares slipped 42 cents, or 0.9%, to $45.05.

Regeneron Pharmaceuticals(REGN Quote) rose 6% after the FDA gave a green light to the company's Arcalyst drug. Arcalyst treats Cryopyrin-Associated Periodic Syndromes, a group of rare, inherited, auto-inflammatory conditions. The company said the condition affects roughly 1 in 1 million people in the United States.

Shares of Regeneron gained $1.13 to $20.03 on the day.

Gilead and Regeneron are both components of the Nasdaq biotechnology index, which slipped 0.01% to 795.39.

In earnings, Nektar(NKTR Quote) reported a quarterly profit of $39 million, or 42 cents a share, reversing a year-earlier loss of $38.9 million, or 43 cents a share. Revenue declined to $65.8 million from $69.9 million the prior year.

The profit comes in light of a $79.2 million gain from the termination of Nektar's agreement with Pfizer for inhalable insulin product Exubera, and also a $22.7 million reduction in cost of goods sold. Analysts, on average, anticipated a fourth-quarter loss of 23 cents a share on revenue of $42.9 million, according to Thomson Financial.

Shares of Nektar rose 67 cents, or 10%, to $7.13.

Medicis(MRX Quote) benefitted from strong sales of acne products Solodyn, Triaz and Ziana, posted a fourth-quarter profit of $27.5 million, or 41 cents a share, up from $17.9 million, or 27 cents a share, during the year-earlier period.

The per-share earnings fell shy of Wall Street estimate of 43 cents. But revenue rose 42% to $140.3 million, beating the Thomson Financial target of $129.5 million.

For 2008, Medicis expects to earn $1.43 to $1.56 a share, on revenue of $528 million to $540 million. Analysts polled by Thomson Financial predict a profit of $1.54 a share, with revenue $524.5 million. Shares of Medicis rose $1.69, or 8.6%, at $21.46.

On the other end, a disappointing outlook sent shares of drug development services company PharmaNet(PDGI Quote) plunging 31%.

The company forecast 2008 earnings of $1.42 to $1.57 a share, with revenue between $401 million and $409 million. The projection falls below analysts forecast of a profit of $1.76 a share on revenue of $414.8 million. Shares of PharmaNet tumbled $12.73 to $28.62.

Osiris(OSIR Quote) fell 7% after the stem-cell company recorded a quarterly loss of $21.6 million, or 73 cents a share, widened from a loss of $12.7 million, or 46 cents a share, a year ago. Revenue climbed to $7.2 million from $3.2 million, beating estimates, but didn't offset charges and higher spending for clinical trials. Analysts expected Osiris to post a loss of 34 cents a share on revenue of $5.7 million.

Its shares declined 81 cents, or 6.9%, to $10.92.