* Amazon buys online pharmacy, hitting drug stocks
* U.S. Q1 GDP growth revised down to 2 pct
* Marvell, Cavium jump after China nod for $6 bln merger
* Futures drop: Dow 0.60 pct, S&P 0.38 pct, Nasdaq 0.48 pct (Adds details, updates prices)
June 28 (Reuters) - Wall Street was set to open lower on Thursday, with drug stocks taking a hit after Amazon's move into the space and as U.S. first-quarter economic growth was revised lower, adding to already heightened tensions over a trade dispute with China.
Amazon said it would buy medications-by-mail company PillPack, which sent shares of drug distributors and suppliers tumbling.
Walgreens Boots, already lower after reporting quarterly results, fell further and was last down 9.5 percent in premarket trading.
Shares of CVS Health sank 9 percent, Rite Aid fell 7.6 percent and Express Scripts declined 3.3 percent. Amazon was marginally higher.
Gross domestic product increased at a 2 percent annual rate in the January-March period, the Commerce Department said in its third estimate for first-quarter GDP, instead of the 2.2 percent pace it reported last month.
The slowdown came amid the weakest performance in consumer spending in nearly five years, but growth appears to have since regained momentum on the back of a robust labor market and tax cuts.
The tepid data also comes as the United States and China have continued their tit-for-tat moves over trade and tariffs as well as Chinese investments in American technologies.
Chipmaker Marvell Technology said it got Chinese regulatory approval for its $6 billion acquisition of smaller rival Cavium Inc. Marvell jumped 7.3 percent, while Cavium rose 9.5 percent.
At 8:59 a.m. ET, Dow e-minis were down 146 points, or 0.60 percent. S&P 500 e-minis were down 10.25 points, or 0.38 percent and Nasdaq 100 e-minis were down 33.75 points, or 0.48 percent.
Accenture rose 2.8 percent after the consulting and outsourcing services provider reported quarterly revenue and profit above estimates. (Reporting by Sruthi Shankar in Bengaluru; Editing by Shounak Dasgupta)