* Silence issuing 79.64 mln shares in reverse takeover deal
* Intradigm CEO to lead merged group under Silence chairman
* Shares down 19 pct at 20p after 2-1/2 month suspension (Adds interview with chairman, quotes, more detail on deal)
By Ben Hirschler
LONDON, Dec 16 (Reuters) - Britain's Silence Therapeutics (SLN.L) has agreed to buy private U.S. biotech firm Intradigm in a share-swap deal worth some 16 million pounds ($26 million) to lift its profile in the emerging field of RNAi medicine.
Chairman Iain Ross told Reuters on Wednesday he expected the enlarged group to clinch at least one major new partnership with a pharmaceutical company in 2010.
But investors were wary and shares in Silence, which were suspended at the end of September when it first announced it was in merger talks, fell 19 percent to 20p as trading resumed.
Silence will issue 79.64 million shares to acquire the entire share capital of Intradigm, giving the Californian company's shareholders and management 36.6 percent of the business on completion.
The British company has also raised 15 million pounds via a share placing at 23 pence per share, and existing shareholders of Intradigm -- including Alta Partners, Frazier Healthcare, Lilly Ventures (LLY.N), Roche Finance ROG.VX and Astellas Venture (4503.T) -- have subscribed for 5 million pounds.
Silence is a small player in the experimental field of drug development known as RNAi, or RNA interference, which is seen as having the potential to produce promising treatments for a number of diseases, including cancer.
RNAi is based on manipulating ribonucleic acid -- the genetic messenger of a cell -- to interfere with or "silence" targeted genes in order to prevent the formation of proteins that can cause diseases.
By joining forces with Intradigm it hopes to develop a more competitive offering that will lead to an increased flow of deals with large pharmaceutical companies.
"We envisage at least one major deal being announced next year," Ross said. "Intradigm also has a pretty spectacular list of Big Pharma shareholders and I wouldn't be surprised if one of those relationships blossomed into a transaction over the next 24 months."
Silence, whose most advanced products are still only in the early stages of clinical development, signed its biggest deal to date with AstraZeneca (AZN.L) in 2007.
Ross will remain as chairman of the enlarged company, while Philip Haworth, chief executive of Intradigm, will be CEO.
Delivering RNAi molecules to diseased tissue is one of the main challenges of the new technology, and the combined group will offer potential partners a choice of approaches. Silence uses a liposomal system, which hangs RNAi molecules on the outside of lipids, while Intradigm uses natural polymers.
The British company was advised by Nomura Code Securities. ($1=.6115 pounds) (Editing by Greg Mahlich and Rupert Winchester)