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Lorus Publishes Preclinical siRNA Data


Lorus Therapeutics reported the publication of preclinical data on its lead siRNA cancer drug, siRNA-1284, marking the first formal announcement of the company’s intention to play in the RNAi-based drugs arena.

According to Jeff Lightfoot, project manager at Lorus, the company has been working on expanding beyond antisense into RNAi for about three years, primarily focusing on molecules that target R2, a subunit of the enzyme ribonucleotide reductase, which is required for DNA synthesis and repair.

After testing several siRNAs, the company settled on siRNA-1284 as the most promising and has put the drug candidate at the top of its RNAi pipeline, says Lightfoot. He adds that the drug is expected to be used to treat solid tumors such as those associated with renal, skin, and colon cancers.

However, Lorus doesn’t expect to rush the RNAi drug into the clinic. Saeid Babaei, associate director of corporate affairs at Lorus, notes that the company is currently prioritizing its research and development projects and expects to focus on those drug candidates already in the clinic. These include the antisense drug GTI-2040, which also targets R2 and is in six phase I and phase II studies for various cancers.

“A major effort [is underway] and resources are being spent for 2040, trying to move the compound forward,” says Babaei. “We don’t have a defined timeline [for the RNAi program] that I can share. It [might] be some time in ’08, [but] it would be too premature to comment” on exact timing.

According to Lorus’ paper, which was published in Anti-Cancer Drugs, siRNA-1284 was successfully used to inhibit the expression of R2 in cancer cell lines and resulted in a significant inhibition of cell proliferation in vitro.

In vivo testing, meanwhile, showed the siRNA was able to significantly inhibit tumor growth in three different mouse models of cancer — renal carcinoma, melanoma, and adenocarcinoma.

Doug Macron

Short Reads

Sigma-Aldrich introduced its first two Mission siRNA druggable genome libraries. These libraries, containing human and rat genomes, are subdivided into 17 gene family panels that can be screened for
gene function.

Inex and Alnylam Pharmaceuticals received a notice of allowance from the US Patent and Trademark Office. Their application concerned nucleic acid-lipid compositions that the companies are using to deliver siRNA-based drugs.

EMD Biosciences signed an exclusive license and supply agreement with Dendritic Nanotechnologies, a subsidiary of Starpharma. EMD Biosciences will be using Dendritic’s dendrimers in DNA and siRNA transfection studies.

Lipomic Technologies signed on to give Isis Pharmaceuticals support for its metabolic disease drugs during its preclinical and clinical trials. Lipomics retains the rights to develop diagnostics, and Isis keeps the therapeutic rights.

Benitec announced a stock rights issue plan designed to raise as much as $5.1 million, which it would use to support its efforts to fend off ongoing litigation with Nucleonics and continue a corporate reorganization.

Cell Therapeutics, which  develops cancer drugs, says it  will create and spin out a company with a technology that may have applications in siRNA delivery. Aequus BioPharma is the spinoff.


US patent application 20070033663. ES cells having enhanced RNAi effect. Inventors: Motoya Katsuki, Mitsuyoshi Ishida, and Minoru Kato. Filed: October 5, 2006.

This patent covers the invention of embryonic stem cells, obtained by genetic manipulations, that have an “enhanced RNAi effect, which can be used to analyze gene functions at an individual level.” These cells are obtained by performing genetic manipulation on embryonic stem cells.

US patent application 20070042984. RNAi modulation of the Rho-A gene and uses thereof. Inventors: Juergen Soutschek, Pamela Tan, and Anke Geick. Filed: July 21, 2006.

This invention covers the composition and method “for modulating the expression of the RhoA gene, and more particularly to the downregulation of RhoA by chemically modified oligonucleotides.”

Data Point

$30 million
Rosetta Genomics sold 562,500 shares of its common stock in an over-allotment option. During its IPO, Rosetta sold 4.3 million common shares, grossing more than $30 million.

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