Benzinga's Top #PreMarket Gainers

shares rose 60.31 percent to $2.10 in pre-market trading. Onconova Therapeutics presented positive data Monday from Phase 2 combination trial of oral Rigosertib And Azacitidine at the ASH 2015.

shares surged 14.89 percent to $55.10 in pre-market trading after dropping 2.24 percent on Monday.

shares climbed 8.50 percent to $21.19 in pre-market trading after the company announced the receipt of an unsolicited bid to be acquired for $21.70 per share in cash.

shares rose 3.27 percent to $20.85 in pre-market trading. Citigroup upgraded FireEye from Neutral to Buy and raised the price target from $31.00 to $35.00.

gained 0.36 percent to $120.44 in pre-market trading. Casey's reported better-than-expected earnings for its fiscal second quarter, but the company's sales missed analysts' estimates.