Gilead Sciences (GILD) shares soared 8.5% in the last trading session to close at $68.49. The move was backed by solid volume with far more shares changing hands than in a normal session. This compares to the stock's 6.9% loss over the past four weeks.The surge is mostly attributable to positive results from the late study PURPOSE 1 wherein twice-yearly lenacapavir demonstrated its potential as a new tool to help prevent HIV infections with zero infections and 100% efficacy.  On the basis of these results, ...