Wednesday, July 27, 2005

Sirna Setting the Stage

Sirna Therapeutics (NASDAQ: RNAI) rocketed yesterday, though naturally some profit taking is occurring today, following very encouraging news of the first demonstration of systemic siRNA efficacy at therapeutically relevant doses, results were published in Nature Biotechnology.

The study demonstrated that Sirna's chemically optimized and encapsulated siRNAs have high potency and prolonged duration of activity in vivo. The siRNA formulation, targeting Hepatitis B Virus, was administered by standard intravenous injection to mice carrying replicating HBV. Three therapeutically relevant doses of 1, 3, or 5 mg/kg resulted in up to a 95% dose dependent reduction in serum HBV DNA levels.

RNA interference (RNAi) is a natural, selective process for turning off genes. RNAi is triggered by short interfering RNA (siRNA) molecules that engage a group of cellular proteins, known as RISC (RNA induced silencing complex). The RISC guides the siRNA to its target messenger RNA (mRNA, the messenger between DNA and proteins) by complementary base pairing for the targeted break-up of the mRNA thus halting protein expression or viral replication. The RISC-siRNA-complex binds and cleaves multiple mRNA molecules in a catalytic fashion.

Sirna Therapeutics recently moved their corporate headquarters to San Francisco though R&D, manufacturing and administrative facilities remain in the Boulder, CO campus.

I’ve been a longtime shareholder of RNAI and have never been more excited about what lay ahead.

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