US STOCKS-GDP lifts Dow over 18k; biotechs have worst day since April

* Q3 GDP revised up to 5 percent annual pace

* Durable goods orders fall short of expectations

* Gains broad, but biotechs have worst day since April

* Dow up 0.6 pct, S&P up 0.3 pct, Nasdaq off 0.3 (Updates to afternoon trading)

By Ryan Vlastelica

NEW YORK, Dec 23 (Reuters) - U.S. stocks rose for a fifth straight session on Tuesday, with the Dow climbing above 18,000 for the first time ever after an unexpectedly strong report on economic growth.

Both the Dow and S&P 500 hit intraday records, and the S&P is on track for its 51st record close of 2014. The gains pushed the Dow as high as 18,051.14, and the blue-chip index is now up about 175 percent from a 12-year low hit on March 9, 2009.

The final estimate for third-quarter U.S. economic growth was revised up to a 5 percent annual pace, its quickest in 11 years and easily topping expectations calling for growth of 4.3 percent.

"Everyone is surprised, and I'm definitely pleased," said Wayne Kaufman, chief market analyst at Phoenix Financial Services in New York. "How can inflation be so low when GDP is so high? Either this is just a one-off and GDP will fall back dramatically, or we'll see a pickup in inflation, which could put more pressure on the Fed."

The report spurred a broad rally, with nine of the ten primary S&P 500 sectors higher on the day. The only group to fall was healthcare, down 2.5 percent alongside a massive drop in biotech stocks.

The Nasdaq biotech index fell 5.4 percent, its biggest one-day decline since April 10. Components of the index made up the top six percentage decliners on the S&P; Celgene Corp fell 8 percent to $104.49 while Biogen lost 6.6 percent to $329.14 and Regeneron Pharmaceuticals (NasdaqGS: REGN - news) lost 6 percent to $388.

Gilead Pharmaceuticals fell 4.5 percent to $88.70, extending Monday's drop of 14 percent, which came after Express Scripts said it would abandon covering Gilead's hepatitis C treatment in favor of a cheaper option.

"This is just a kneejerk reaction, based on a bear thesis that Express Scripts will start to dictate prices," said Kaufman. "I don't see how this is any different than any other company in another sector getting more competition. Soon people will go through the stocks one-by-one to see which got oversold."

At 1:10 p.m. (1810 GMT) the Dow Jones industrial average rose 99.21 points, or 0.55 percent, to 18,058.65, the S&P 500 gained 5.72 points, or 0.28 percent, to 2,084.26 and the Nasdaq Composite dropped 12.25 points, or 0.26 percent, to 4,769.17.

In addition to the GDP report, data showed a solid rise in consumer spending while consumer sentiment hit its highest level in nearly eight years. Separately, durable goods orders unexpectedly fell in November while new home sales fell for a second straight month.

Trading volume is expected to be light this week due to the Christmas holiday, which could increase volatility. U.S. equity markets will open for an abbreviated session Wednesday and be closed on Thursday.

Advancing issues outnumbered declining ones on the NYSE by 2,086 to 932, for a 2.24-to-1 ratio on the upside; on the Nasdaq, 1,463 issues rose and 1,222 fell for a 1.20-to-1 ratio favoring advancers.

The benchmark S&P 500 index was posting 113 new 52-week highs and 5 new lows; the Nasdaq Composite was recording 164 new highs and 42 new lows. (Editing by Christian Plumb)