(Rewrites, adds background on dispute, share price)
By Natalie Grover and Michael Erman
July 7 (Reuters) - Eli Lilly and Co won a years-long patent dispute with Actavis on Friday after the UK Supreme Court ruled that the generic drugmaker's versions of Lilly's top-selling cancer drug Alimta directly infringe on certain Lilly patents in Britain, France, Italy and Spain.
Teva Pharmaceutical Industries Ltd owns the generic versions of Alimta in question after buying Allergan Plc's generic business Actavis last August.
Alimta, whose chemical name is pemetrexed, is Lilly's top-selling oncology treatment and generated sales of $2.3 billion last year.
This decision applies to about $300 million worth of annual sales, Evercore ISI's Umer Raffat said.
The court's key conclusions confirm that the Alimta vitamin regimen patent would be infringed by these generic pemetrexed products in Britain, France, Italy and Spain prior to June 2021, said Michael Harrington, senior vice president and general counsel for Lilly.
The court also upheld the indirect infringement finding by the UK Court of Appeal, Lilly said, adding that the full judgment is expected by Wednesday.
In major European countries, the basic compound patents for Alimta expired in December 2015 but its vitamin regimen patents run until June 2021.
The so-called vitamin regimen patent in question covers a method in which patients take folic acid and vitamin B12 prior to Alimta, to reduce the drug's toxicity and allow it to interrupt the ability of cancer cells to reproduce.
The UK Court of Appeal in June 2015 ruled that the Alimta vitamin regimen patent would be indirectly, not directly, infringed when the generic product is reconstituted or diluted in saline.
The announcement on Friday implies that the UK Supreme Court found the Actavis product being infringed, regardless of the diluent used, Lilly said.
A U.S. appeals court ruled in favor of Lilly in a similar case in January. It still faces a review of the issue by the U.S. Patent Trial and Appeal Board, which analysts said could result in further appeals if it is not in Lilly's favor.
Teva could not be immediately reached for comment.
Shares of Lilly rose 30 cents to $81.90 on the New York Stock Exchange on Friday morning. Teva's U.S. shares fell 25 cents, or 0.8 percent, to $31.52. (Reporting by Natalie Grover in Bengaluru and Michael Erman in New York; Editing by Saumyadeb Chakrabarty and Bill Rigby)