U.S. stocks extended gains on Tuesday, boosted by Intel Corp, Apple Inc and biotechnology shares, with the Nasdaq Composite briefly up 1 percent.

The Dow Jones industrial average <.DJI> added 56.38 points, or 0.52 percent, to 10,841.52. The Standard & Poor's 500 Index <.SPX> gained 7.32 points, or 0.63 percent, to 1,167.05. The Nasdaq Composite Index <.IXIC> rose 21.75 points, or 0.92 percent, to 2,396.42.

Biotech stocks rose after Gilead Sciences Inc unveiled a large stock-buyback program and Intel gained after it forecast annual earnings growth to double over the next few years.

The top gainer on the Nasdaq was Apple Inc , up 2.2 percent to $259.50.

(Editing by Padraic Cassidy)