Updated from 2:59 p.m. EDTShares of Dyax ( DYAX) were among the worst-performing health and pharmaceutical stocks Friday, falling 24.7% after the company posted mixed third-quarter financial results and provided guidance on its DX-88 drug program. The biotherapeutics company posted a third-quarter loss of 25 cents a share on sales of $3.3 million. Analysts polled by Thomson First Call were expecting a loss of 27 cents a share on sales of $4.6 million. A year ago, the company posted a loss of 25 cents a share on sales of $5.9 million. In addition to its earnings announcement, Dyax also said it expects to file a biologics license application for its hereditary angioedema drug with the Food and Drug Administration some time after 2005. Dyax and its partner, Genzyme ( GENZ), are in "ongoing discussions with the agency to plan additional clinical work that will be required" before it files its application. Dyax said it remains confident that it can advance DX-88 to the commercialization stage. Earlier this month the drug received fast-track designation from the FDA. Shares traded down $1.99 to $6.08. McKesson ( MCK) rose 8.7% after the drug wholesaler turned in second-quarter earnings results that were better than expected. The company earned 29 cents a share on a 19% jump in sales, which came in at $19.9 billion. Analysts were expecting earnings of 24 cents a share during the quarter. A new agreement with the Department of Veteran Affairs, the acquisition of AdvancePCS, and strength in its Canadian business accounted for the strong sales results during the quarter. Looking ahead, McKesson expects full-year earnings of $2 to $2.20 a share, down from previous guidance of $2.20 to $2.35 a share, which it issued just last month. Analysts are expecting earnings of $2.09 a share. Shares traded up $2 to $24.98. Shares of Iridex ( IRIX) fell 37% after the company announced that its laser treatment for age-related blindness did not demonstrate a significant difference compared to a placebo. The company said that 47% of patients treated with its Transpupillary Thermotherapy laser treatment avoided modest or severe vision loss compared to 43% who did not use the treatment. Iridex said the difference between the two was "not statistically significant." Shares traded down $2.64 to $4.50. Gilead Sciences ( GILD) fell 9.4% after the company posted third-quarter earnings results. The biopharmaceutical company earned 25 cents a share during the quarter on sales of $326.2 million. Analysts were expecting earnings of 21 cents a share on sales of $318.7 million.