US STOCKS-Futures advance after three-day rally; data on tap
* Futures up: Dow 60 pts, S&P 5.75 pts, Nasdaq 2.75 pts
* Gilead falls as Express Scripts chooses AbbVie treatment
* Biocryst gets FDA OK for intravenous flu drug (Adds premarket actives data)
By Chuck Mikolajczak
NEW YORK, Dec 22 (Reuters) - U.S. stock index futures advanced on Monday, after the S&P 500 notched its best weekly performance in almost two months, ahead of data on the housing market.
* Brent crude hit a high of $62.97 and WTI crude rose to as much as $58.53 amid investor confidence there would be no substantial price loss in the run-up to the new year. Brent last traded down 21 cents at $61.17 while U.S. crude was last off 0.7 percent at $56.74 after Saudi Arabia indicated it could increase its output.
* The benchmark S&P index rose 3.4 percent last week, boosted by a 5 percent jump over three sessions, after the U.S. Federal Reserve said it would take a "patient" approach toward raising interest rates and oil prices appeared to stabilize. The S&P energy index surged nearly 10 percent for the week.
* Investors await existing home sales data, due out at 10:00 a.m. (1500 GMT). Expectations are for a decline of 1 percent.
* Trading volume is expected to be light this week due to the Christmas holiday, which could increase volatility. U.S. equity markets will operate a shortened session on Wednesday and be closed on Thursday. Continuación...