Arrowhead Research Subsidiary Granted China RNAi Patent

Calando Pharmaceuticals of Pasadena, CA, received a China patent for broad coverage of all methods of using any RNA interference construct formulated in a supramolecular complex. Supramolecular complex formulations are those formed with any type of polymer. The patent also covers any pharmaceutical compositions of matter containing RNAi constructs adapted for pulmonary or nasal delivery to the lungs.

Calando Pharma is a majority owned subsidiary of Arrowhead Research Corp. (NSDQ: ARWR).

The China patent covers a basis for delivery of RNAi-based drugs, though in the case of respiratory-delivered pharmaceuticals, the patent is not limited to any specific mode of siRNA delivery.

In the US, the FDA has given Calando the go-ahead to begin Phase I trials of CALAA-01, making it the first clinical study using targeted, systemic delivery of siRNA and the first siRNA trial in oncology.

Calando’s RONDEL technology involves the use of cyclodextrin-containing polymers that 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 smaller than 100 nm in 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.

Disclosure: none.

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