Alnylam generates preclinical buzz with RNAi hemophilia drug

Executives from Alnylam Pharmaceuticals ($ALNY) trekked to Paris on July 8-12 to tout positive preclinical trial results for ALN-AT3, a new RNAi drug designed to treat hemophilia. The Cambridge, MA, company was one of many to share data at the World Federation of Hemophilia World Congress. Armed with that promising news, Alnylam now plans to submit an investigational new drug application for the compound in 2013.

Proof-of-concept results showed that ALN-AT3 in mice and "non-human primate" studies helped increased thrombin production, an enzyme necessary to help blood clot properly. Furthermore, researchers determined that antithrombin (as opposed to protein C) is the best target for the drug, an endogeneous protein that blocks generation of thrombin in the body. ALN-AT3 uses Alnylam's GalNAc-SiRNA drug delivery technology.

Alnylam said it also presented related data supporting administering the drug under the skin. This approach, the company said, led to "durable silencing" of antithrombin in the animal trials, which in turn showed that the result could lead to normal thrombin generation in hemophilia patients. Researchers tested various dosing levels, and determined that a once-weekly or twice monthly subcutaneous dose seemed to be effective.

The good news comes even as companies continue to struggle in developing successful RNAi drugs. Alnylam cut a third of its jobs earlier this year in order to double down on its drug development, focusing on programs for hemophilia and transthyretin-mediated amyloidosis, though neither program has yet advanced a drug beyond Phase I. So while promising preclinical results are worth noting, there is a long way to go before the company can determine if its drug will ultimately be viable in people.

Meanwhile, a number of companies are focused on developing new hemophilia treatments in general. They're at various stages, and results so far are mixed.

Ipsen ($IPN), for example, is developing a new hemophilia drug, but the FDA recently put two Phase III studies of the drug on hold. The reason: development partner Inspiration Biopharmaceuticals discovered that patients taking the drug developed antibodies to a protein in it. Medgenics ($MDGN), on the other hand, is pursuing development of a therapeutic protein delivery pump, which could treat hemophilia and anemia, in part, by using a patient's own skin biopsy to produce and deliver therapeutic proteins. The company recently nailed down $9.5 million in private placement funding to propel additional clinical trials for its product.

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