US STOCKS-Wall St reverses course to trade lower as health stocks drag
* Apple shares up ahead of results
* Amgen's fall drags downs biotech stocks
* Celladon nosedives on lead drug's trial failure
* Indexes down: Dow 0.2 pct, S&P 0.3 pct, Nasdaq 0.4 pct (Updates to early afternoon)
By Tanya Agrawal
April 27 (Reuters) - U.S. stocks reversed course to move lower in early afternoon trading on Monday as healthcare stocks led by Amgen dragged on the three major indexes.
The S&P Healthcare index was down 1.32 percent, with Amgen's 3 percent drop to $163.02 the biggest drag on both the S&P 500 and the Nasdaq.
The Nasdaq Biotech index was down 3.5 percent as Celladon plunged about 81 percent to a record low of $2.62.
U.S. Food and Drug Administration staff reviewers said Amgen's skin cancer immunotherapy cannot be considered for an accelerated review at this time, citing concerns over the design and results of a key study. Continuación...