Actavis chases biosimilar drugs via Bioton deal

* Actavis in talks to buy 51 pct of Bioton’s BioPartners

* Move to give Icelandic firm platform in biosimilar drugs

LONDON, Sept 7 (Reuters) - Icelandic drugmaker Actavis said on Tuesday it aimed to join the race to develop generic copies of pricey biotech medicines by buying a majority stake in Polish group Bioton's BOTN.WA BioPartners unit.

Actavis, one of the world’s largest generic drugmakers, will perform due diligence on BioPartners and has exclusive rights to discuss acquiring 51 percent of the business until Nov. 1. Financial terms have not yet been agreed.

Actavis is also discussing the possibility of distributing insulin and certain other products made by Bioton.

The so-called biosimilars market could be worth an estimated $10 billion in annual sales by 2015, according to analysts, and is viewed as a high-margin growth opportunity by makers of generic drugs.

It is more difficult to develop complex biotech medicines than conventional chemical drugs.

"Only the large generic players such as Teva TEVA.O, (Novartis NOVN.VX unit) Sandoz, Mylan MYL.O and Actavis have the capability to do this," Actavis CEO Claudio Albrecht said in a statement.

Biologics, made from proteins that can be more than 800 times the size of molecules found in conventional medicines, are often the only treatment option against serious diseases such as cancer, multiple sclerosis and rheumatoid arthritis.

In July, Actavis and owner Bjorgolfur Thor Bjorgolfsson agreed a refinancing deal with lenders led by Deutsche Bank DBKGn.DE to slash its billions of euros in debt. [ID:nLDE66L1B0] (Reporting by Ben Hirschler; Editing by Hans Peters)