Check out which companies are making headlines after the bell:
Shares of Merck fell more than 2 percent during after-hours trading following a pause in enrollment for two studies of Keytruda, its drug to treat multiple myeloma, due to an imbalance in patient deaths. Multiple myeloma is a cancer of plasma cells, the white blood cells responsible for producing antibodies. Merck said in a statement that the studies have been paused to "allow for additional information to be collected" to understand the multiple deaths.
Science Applications International shares tanked more than 12 percent during extended trading after the company reported mixed results for its fiscal first-quarter. Science Applications reported earnings of $1.08 per share on revenue of $1.1 billion while Wall Street expected earnings of $1.04 per share on revenue of $1.12 billion, according to Thomson Reuters consensus estimates.
Acceleron Pharma shares pulled back nearly 8 percent during after-hours trading following an update stating that phase-2 trials for Dalantercept, a drug to treat advanced renal cell carcinoma, "did not achieve its primary endpoint" to demonstrate an increase in progression-free survival.
Shares of Synaptics slipped 1 percent during extended trading after the technology company announced that it would acquire Conexant, a provider of audio and voice technology solutions, and Marvell Technology Group's Multimedia Solutions Business, a provider for video and audio processing technologies. Synaptics said it believes the acquisitions will help "jumpstart" its presence in the smart home market.