* Obama slaps U.S. sanctions on more Russians over Ukraine
* Pfizer works on next move in takeover bid for Astrazeneca
* Futures up: Dow 40 pts; S&P 5.6 pts; Nasdaq 10.5 pts
NEW YORK, April 28 U.S. stock index futures rose on Monday, rebounding from sharp losses on Friday, boosted by merger and acquisition activity in the pharmaceuticals sector.
* U.S. drugmaker Pfizer Inc is working on its next move in a potential $100 billion bid to take over Britain's AstraZeneca Plc after having two bids rejected.
* Pfizer made a 58.8 billion pounds ($98.9 billion) bid to AstraZeneca in January and said it had contacted its British rival again on April 26 to further discuss a takeover, which would be one of the biggest ever in the pharmaceuticals industry.
* In earnings, Charter Communications Inc reported a 15 percent jump in first-quarter revenue due to a rise in the number of residential video subscribers. The stock closed at $130.01 on Friday.
* U.S. March pending home sales data is due at 10:00 a.m. ET (1400 GMT), followed by the Dallas Fed Manufacturing Survey at 10:30 a.m.
* S&P 500 e-mini futures rose 5.6 points and were above fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures rose 40 points and Nasdaq 100 futures added 10.5 points.
* U.S. President Barack Obama announced new sanctions against some Russians on Monday to stop President Vladimir Putin from fomenting the rebellion in eastern Ukraine, but said he was holding broader measures against Russia's economy "in reserve."
* U.S. stocks dropped on Friday, weighed by a selloff in consumer discretionary stocks as bellwether names Amazon.com and Ford Motor fell in the wake of their quarterly earnings. Amazon.com shares were up 0.1 percent in premarket trade on Monday.
* Despite Friday's decline, the S&P 500 finished nearly flat for the week and within 2 percent of its all-time intraday high. (Editing by Bernadette Baum)