Perhaps the lingering delivery hurdle is why Patrick Lu, founder of RNAi and gene-based therapeutics company Intradigm, reacted positively to the news of the Alnylam-Ribopharma merger.
"I think it's very encouraging news," Lu told GenomeWeb, "I think it creates another critical mass for the field."
Lu, who is the executive vice president of Intradigm, said that both Alnylam and Sirna are talking to Intradigm because of its expertise with target delivery systems. The company has developed a pulmonary delivery system, through which siRNA can be delivered to cells in the lung, as well as a joint delivery system, a tumor delivery system, and a systematic target delivery system that can deliver siRNA to new vasculature such as tumors and inflammation.
Intradigm announced a collaboration with Qiagen Tuesday to use Qiagen's siRNA's in its therapeutic development efforts. This deal, said Lu, "means we can access their TOM [amidite chemistry] technology-based siRNA synthetic oligos, and they can use Intradigm's platform to demonstrate [that] their specific, patented oligos [are> also very useful for target validation as a research tool and potential therapeutic."
Lu emphasized that the deal is non-exclusive and that Intradigm also may decide to use siRNA from other providers.
Intradigm plans to assess the use of Qiagen's siRNA oligos in achieving endogenous knockdown in arthritis, oncology, and the SARS coronavirus. In this last area, the company has already used its pulmonary delivery vehicle to use siRNA to treat SARS virus infection in the mouse, and is now doing toxicology studies on different siRNAs.
Now, Intradigm has sent its siRNA both to the National Institute of Allergy and Infectious Diseases to test the siRNA molecules, as well as another collaborator, Top Biotech LTD, which is based in Hong Kong and Guangdong, China. Top Biotech is working with a non-human primate animal model. Intradigm is using its own funds for the project.
In research news, a team from the University of Texas Southwestern Medical Center and Proligo of Boulder, Colo., published a paper in the July 8 issue of Biochemistry, in which they described that chemical modification of RNAi increases its stability, potency, and potential clinical efficacy. They report that RNA duplexes with phosphorothioate or phosphodiester linkages were stable during long periods of incubation in serum, and that the RNAi with the phosphorothioate linkages selectively inhibited gene expression. They also found that introducing Proligo's locked nucleic acid nucleotides also increased the thermal stability of these duplexes and did not render it less effective.
While several conferences so far have integrated RNAi into their programs, the first-ever virtual conference on the subject is to take place next Tuesday, July 15, between 12:00PM and 1:30 PM EST. Nassim Usman, chief scientific officer and vice president of R&D at Sirna Therapeutics, will be the presenter, and will be monitored by Barry Polisky, vice president of research at Sirna. For more information, go to http://www.genengnews.com/seminars/rnai.htm.（By Marian Moser Jones）
