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* First full quarter of Crestor generics in U.S. market
* Tax gain, cost cuts, externalisation offset sales fall
* Q3 revenue $5.7 billion vs consensus $5.9 billion
* Q3 core EPS $1.32 vs consensus 97 cents (Adds shares, further details on tax gain)
By Ben Hirschler
LONDON, Nov 10 (Reuters) - Competition from multiple genericversions of its cholesterol fighter Crestor hit AstraZeneca's third-quarter sales but a one-off tax gain, cost cutsand income from disposals propped up earnings.
The drugmaker enjoyed a tax benefit of $453 million due toagreements on transfer pricing arrangements between Canadian,British and Swedish tax authorities.
Revenue in the quarter declined 4 percent to $5.7 billionbut core earnings per share (EPS), which exclude some items,rose 28 percent to $1.32, the British company said on Thursday.
Industry analysts had on average forecast quarterly revenueof $5.90 billion and earnings of 97 cents a share, according toThomson Reuters.
Shares in AstraZeneca slipped 0.7 percent in early tradingas the group reiterated its forecast of a low to midsingle-digit percentage decline in both revenue and coreearnings at constant exchange rates for the full year.
Sales of new cancer drugs Tagrisso and Lynparza were brightspots in the quarter, while income from "externalisation" deals,involving the sale of certain rights to products, totalled $674million.
Selling, general and administrative costs fell by 12 percentto $1.9 billion as the company increased its focus on itsprimary therapy areas. Research spending was stable at $1.3billion.
"The performance in the third quarter was in line with ourexpectations, reflecting the transitional impact from the firstfull quarter of generic competition to Crestor in the U.S.,"Chief Executive Pascal Soriot said in a statement.
AstraZeneca's long-term prospects hinge on its roster of newcancer drugs, with investors focused especially on a trialcombining its immunotherapies durvalumab and tremelimumab, whichwill report results in lung cancer in the first half of 2017.
The recent failure of Bristol-Myers Squibb's rivalimmunotherapy Opdivo in previously untreated lung patients hasopened up the market opportunity, but there is no certaintyAstraZeneca's trial will hit its goal.
A sharp share price fall last month on a setback in twostudies testing durvalumab in head and neck cancer shows thenervousness surrounding the firm's big cancer bet.
Unlike British rival GlaxoSmithKline, which haslower-risk businesses such as consumer healthcare to buttressrisky drug research, AstraZeneca is focused solely on findingnew prescription medicines.
Soriot saw off a $100 billion takeover attempt by Pfizer in 2014 but the company has remained subject to takeoverspeculation.
On the research front, AstraZeneca said it now expected thefirst submission for regulatory approval of its new blood cancerdrug acalabrutinib to be made in the first half of 2017. (Editing by Jason Neely and Jane Merriman)
