( strates potent anti-proliferative activ...)Calando Pharmaceuticals Announces Preclinical Efficacy and Safety,Data of Targeted, Systemic Delivery of siRNA at AACR Annual Meeting,Health

"These studies were performed to demonstrate both the safety and efficacy of this siRNA-containing formulation in animals," said Jeremy Heidel, Chief Scientific Officer at Calando Pharmaceuticals. "This formulation was well-tolerated in mice and monkeys at concentrations that elicited a significant anti-tumor effect in a murine cancer model. These results suggest that this formulation has promise for human use."

Calando's cyclodextrin-containing polymers form the foundation for its two-part siRNA delivery system. The first component is a linear, cyclodextrin-containing polycation that, when mixed with small interfering RNA (siRNA), binds to the anionic "backbone" of the siRNA. The polymer and siRNA self-assemble into nanoparticles of approximately 50-80 nm diameter that fully protect the siRNA from nuclease degradation in serum. The siRNA delivery system has been designed to allow for intravenous injection. Upon delivery to the target cell, the targeting ligand binds to membrane receptors on the cell surface and the RNA-containing nanoparticle is taken into the cell by endocytosis. There, chemistry built into the polymer functions to unpackage the siRNA from the delivery vehicle. In addition to targeting tumors, the targeting of liver cells has also been accomplished in vivo.

About Calando Pharmaceuticals Inc.

Calando Pharmaceuticals Inc. (www.calandopharma.com), a majority-owned subsidiary of Arrowhead Research , is using its proprietary technologies in targeted polymeric delivery systems and siRNA design to design and create new, targeted siRNA therapeutics. Small interfering RNAs (siRNA) induce RNA interference, or RNAi, a naturally occurring mechanism within cells to selectively silence and regulate specific genes. The ability to silence genes through RNAi could provide a n
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