NEW YORK ( TheStreet) -- Gilead Sciences ( GILD) was the best-performing stock in the S&P 500 on Thursday morning. The S&P 500 was dropping 1.74 points, or 0.13%, to 1,383.40.
Shares of Gilead Sciences were rising 14.67% Thursday morning to $53.45. The stock is rising based on results from Gilead Sciences' hepatitis C tests. The company's "Electron" study of GS-7977 has an early cure rate of 88%. Gilead Sciences has an estimated price-to-earnings ratio for next year of 12.39 times; the average for biotechnology companies is 29.95. For comparison, Amgen ( AMGN) has a lower forward P/E of 10.01; Celgene's ( CELG) forward P/E is 14. Twenty-six of the 33 analysts who cover Gilead Sciences rated it buy; seven analysts gave the stock a hold rating. TheStreet Ratings gives Gilead Sciences an A- grade with a buy rating and $57.34 price target. The stock has risen 30.64% year to date.