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Dicerna Pharma Gets $25M Boost to Develop Next-Gen Gene Silencing Drugs

Xconomy Boston — 

Dicerna Pharmaceuticals has replenished its war chest. The Watertown, MA-based developer of gene-silencing drugs has raised $25 million in its Series B round of financing to advance its research. It’s a touchdown for Doug Fambrough, who said he made closing this funding round his first major priority when he took over as the firm’s chief executive in early May.

Domain Associates, Dicerna’s new venture investor, led the second-round financing. Dicerna’s existing backers—Abingworth, Oxford Bioscience Partners, and Skyline Ventures—also took part in the financing round. Since formed in 2007, Dicerna has raised a total of $46.4 million in venture capital. (The firm’s $5 million debt financing in June became part of its Series B round, Fambrough said.) With his firm’s new investment, Domain partner Brian Halak is taking a seat on Dicerna’s board.

The deal is a major plug for Dicerna’s unique approach to RNA interference, which involves silencing specific disease-related genes. The firm uses gene-silencing molecules that are a bit longer than traditional short-interfering RNA (siRNA) molecules under development at company’s such as Cambridge, MA-based Alnylam Pharmaceuticals (NASDAQ:ALNY) and Sirna Therapeutics/Merck in San Francisco. Dicerna’s drugs also interact with an enzyme called dicer, which the firm says acts earlier in the gene-silencing process than typical siRNAs. (Dicerna, which has not yet tested any of its drugs in humans, plans to develop its first drug for an undisclosed target against solid tumors.)

There’s yet another key difference in Dicerna‘s drug molecules that could make them suited to overcome a major problem in RNAi drug research: Delivering the molecules deep into the body. The firms’ dicer drugs have a built-in “linker” piece that can attach to numerous molecules such as antibodies, peptides, and lipid-based particles that can deliver them to cells, where they can pack their gene-silencing punch. In its collaboration with Paris-based biotech firm Ipsen, for example, Dicerna is researching whether it can link its RNAi drugs to Ipsen’s peptide molecules.

“Delivery is the key element of this field,” Fambrough said. “I think one of the reasons that this round came together rather quickly, and we were able to get the interest that we got, is the promise of” linking our drugs to other molecules to deliver them to cells.

When Fambrough took to the fund-raising trail after he became the CEO in May, he did so with a lot of experience with both the company and venture investing. He was a founding investor in Dicerna and a general partner at Boston’s Oxford, which led Dicerna’s $21.4 million Series A round in November 2007. During his Oxford days, Fambrough also made a successful bet on the RNAi drug developer Sirna, which Whitehouse Station, NJ-based Merck (NYSE:MRK) scooped up for $1.1 billion in 2006.

Despite the influx of capital, Fambrough said the company doesn’t plan to go it alone. The company’s strategy is to form collaborations with outside drug companies around specific uses of the startup’s technology. (The CEO declined to say how long he expected the second-round dollars to support his firm’s operations.) In January, Dicerna revealed its first collaboration with a major drugmaker, Japan-based Kyowa Hakko Kirin, initially to develop an RNAi drug against an undisclosed cancer target. That deal brought in $4 million in cash upfront, with the potential to bring in up to $1.4 billion in milestone payments. The firm’s Ipsen collaboration was announced in March, but no financial figures were provided.

Indeed, many major drug companies have struck deals with RNAi firms or formed research groups to gain a foothold in RNAi. Alnylam, for example, has either licensed its RNAi technology or partnered with such giant drugmakers as GlaxoSmithKline, Novartis, Roche, and Takeda Pharmaceutical. Before its deal with Dicerna, Kyowa hooked up with Alnylam in June 2008 to develop and potentially sell Alnylam’s experimental RNAi drug for respiratory syncytial virus infection in Asian markets.

Still, Dicerna says it has always believed that its gene-silencing method offers a separate and unique door into RNAi. Also, its gene-silencing drugs hold promise to knock down disease targets which previous drugs have been unable to hit. In lab mice, for instance, Dicerna has shown that its gene-silencing molecules can block expression of a cancer gene called KRAS that has evaded small molecule drugs. The gene plays a key role in cancer progression in leukemia as well as solid tumors of the lung, colon, rectum, and pancreas.