* No U.S. approval for rival Lilly, Amylin diabetes drug
* Analysts: Bydureon delay good news for Novo's Victoza
* Novo says Victoza to do well with or without Bydureon
* Novo shares up 7.4 percent, after 2-day dive
By Anna Ringstrom
COPENHAGEN, Oct 20 (Reuters) - A surprise delay for a potential rival to Novo Nordisk's new key diabetes drug Victoza boosted hopes for the latter, sending Novo's shares soaring on Wednesday after two days of heavy losses.
The U.S. Food and Drug Administration, widely expected to approve Amylin Pharmaceuticals Inc's and Eli Lilly and Co's drug Bydureon this week, has instead requested more studies.
"Assuming an 18-month delay to competition to Victoza, this boosts 2011-13 earnings per share estimates by 1.5 percent to 3 percent," Danske Bank analysts said in a note to clients, keeping a "hold" rating and 470-crown target on Novo stock.
Shares in the world's biggest insulin maker rose 7.4 percent to 529.50 crowns by 0959 GMT, while the STOXX 600 European healthcare index was up 0.8 percent.
The surge followed a near-10 percent dive over the past two days on fears of cut-price insulin competition after Pfizer agreed to market so-called biosimilar insulins being developed by India's Biocon.
Analysts at Jefferies International called news of the Bydureon delay a "huge windfall" for Novo.
"We expect this to provide a long-term benefit to the U.S. market penetration of Victoza as well as allow other later entrants into the market to gain incremental share versus our prior expectations," they said in a note, repeating a "buy" and 600-crown target price.
Victoza is a once-daily version of the new-generation GLP-1 type of drug which stimulates cells to release natural insulin when blood sugar levels are high.
Novo began rolling out Victoza, which it hopes will become a blockbuster with sales of more than $1 billion, in Europe last year. It appeared in the all-important U.S. market in February, and more recently in Japan and Canada.
Bydureon is a once-weekly form of twice-daily Byetta, the only other GLP-1 on the market besides Victoza.
"It appears Bydureon has been delayed until at least 2012. All else being equal, this is a competitive advantage for Victoza," Novo Nordisk spokesman Mike Rulis said.
"Having said that, as we have maintained all along, Victoza will do well whether or not Bydureon is on the market."
Rulis said Novo expects no new GLP-1 drugs to enter the market before 2012. Novo will comment on sales developments for Victoza in its third-quarter report on Oct. 27, he added.
(Reporting by Anna Ringstrom; editing by David Hulmes)