* Blackberry falls in premarket after results
* Brent holds near $60 a barrel
* Futures up: Dow 51 pts, S&P 5.5 pts, Nasdaq 17 pts (Adds premarket actives data)
By Chuck Mikolajczak
NEW YORK, Dec 19 (Reuters) - U.S. stock index futures climbed on Friday, and the benchmark S&P 500 index was poised to continue to rally after its best two-day run in three years.
* The S&P has climbed 4.5 percent over the past two sessions, spurred by the U.S. Federal Reserve's commitment on Wednesday to take a "patient" approach toward raising interest rates while signaling it was on track to raise rates in 2015. That provided clarity and relief to investors over the policy outlook, analysts said.
* Brent crude oil rose hovered near $60 a barrel on Friday, recovering from near a 5-1/2-year low while WTI crude advanced 0.8 percent to $54.54.
* Stocks may experience volatility on Friday as a result of "quadruple witching," the expiration of stock options, index options, index futures and single-stock futures. In addition, the rebalance of the S&P 500 is scheduled to take effect after the close.
* U.S.-listed shares of Blackberry dropped 4.7 percent to $9.60 in premarket after the company posted a small adjusted third-quarter profit and returned to positive cash flow, but revenue declined more than expected. The stock was the most actively traded issue on the Nasdaq before the opening bell with volume of over 1.3 million
* Cerus Corp shares jumped 13.6 percent to $7 before the opening bell after the company said the U.S. Food and Drug Administration approved its blood transfusion device for platelets.
* Ally Financial was the most actively traded stock on the New York Stock Exchange in premarket, up 5.5 percent to $24 on volume of over 1.5 million. The company said the U.S. Treasury Department will sell its remaining 54.9 million shares of the company acquired under the government's bailout of the auto lender.
Futures snapshot at 8:16 a.m. EST (1316 GMT):
* S&P 500 e-minis were up 5.5 points, or 0.28 percent, with 239,898 contracts changing hands.
* Nasdaq 100 e-minis were up 17 points, or 0.3 percent, in volume of 5,385 contracts.
* Dow e-minis were up 51 points, or 0.33 percent, with 35.378 contracts changing hands. (Editing by Bernadette Baum)