UPDATE 2-AstraZeneca buys rights to Forest Labs antibiotic

* AZ to co-develop ceftaroline outside U.S., Canada, Japan

* AstraZeneca increases presence in anti-infectives

* Forest to get unspecified payments and royalties

* Deal boosts hopes for Forest drug, shares up 2.4 pct

(Adds analyst comment, latest shares)

By Ben Hirschler

LONDON, Aug 12 (Reuters) - AstraZeneca (AZN.L) has bought rights to Forest Laboratories' (FRX.N) new antibiotic drug ceftaroline, boosting sales hopes and increasing the Anglo-Swedish drugmaker's presence in anti-infectives.

AstraZeneca will co-develop and commercialise the next-generation cephalosporin medicine, which is in the final stages of development, in all markets outside the United States, Canada and Japan.

It will pay Forest an undisclosed signing fee, milestone payments and sales-related royalties, the two companies said on Wednesday.

Shares in Forest rose 2.4 percent in early trade, while AstraZeneca was 1 percent higher by 1400 GMT.

Corey Davis, an analyst at Natixis Bleichroeder in New York, said AstraZeneca would not have snagged the drug without expecting big sales.

"Instead of the $150 million to $200 million (a year) potential the Street seems to be assigning to ceftaroline, we think it is more like $500 million in the U.S. alone," he said in a research note.

"Our guess is that AstraZeneca is also assuming somewhere around $500 million peak potential ex-U.S."

Forest was likely to receive a modest $20 million or so upfront but could be in line for royalty payments on sales of between 20 and 30 percent, Davis added.

The tie-up is the second collaboration this week by U.S.-based specialty pharmaceuticals group Forest. On Monday, it paid $100 million upfront for U.S. rights to Nycomed's [NYCMD.UL] promising "smoker's lung" drug Daxas. [ID:nLA317359]

Ceftaroline is being developed for the treatment of complicated skin infections, including ones caused by the "superbugs" methicillin-resistant Staphylococcus aureus (MRSA) and multi-drug resistant Streptococcus pneumoniae (MDRSP).

Forest expects to file for U.S. regulatory approval of the drug by the end of 2009, and AstraZeneca plans to submit it in Europe by the end of 2010.

Antibiotic research has been a relatively neglected area of research for big drug companies over the last two decades but it is now starting to move back into the pharmaceutical mainstream as the threat from superbug infections increases.

AstraZeneca is also working on a sepsis drug called CytoFab, developed by British biotech company BTG (BGC.L), and said last month it was starting a large mid-stage clinical trial of the product. [ID:nLT446106]

"This collaboration complements our existing antibiotic Merrem, and our significant investment in antibiotic research, as well as agents in development such as CytoFab," said AstraZeneca Chief Executive David Brennan.

AstraZeneca has a significant in-house research effort into novel antibiotics, with a bacterial infection research site in Boston and a research group working on tuberculosis in Bangalore.

Forest has conducted four pivotal Phase III trials with ceftaroline. The studies showed that versus currently marketed comparators, ceftaroline was active against gram-positive and gram-negative pathogens and was generally well tolerated. (Editing by Will Waterman and David Cowell)