Tekmira Data Shows Improvements in SNALP Therapeutic Index, Publishes Data on Cancer Drug Candidate
Tekmira Pharmaceuticals this week announced the presentation of data showing that the therapeutic index of its stable nucleic acid lipid particles could be improved five to ten times over existing versions of the siRNA delivery technology through the incorporation of novel lipids.
The company said the data were unveiled at Asia TIDES Oligonucleotide and Peptide Technology and Product Development Conference in Tokyo.
"These improvements were made with SNALP formulations designed for delivery of siRNA to targets both in and outside of the liver," Tekmira said. "Furthermore, the formulation improvements were achieved without inducing adaptive immune responses."
Separately this week, Tekmira researchers published data in the Journal of Clinical Investigation showing that SNALP-based delivery of siRNAs targeting polo-like kinase 1 can effectively kill cancer cells and decrease tumor burden in mouse models.
Tekmira is developing an siRNA-based drug against PLK1 as a treatment for solid tumors. The company expects to begin clinical testing of the treatment in the second half of this year (see RNAi News, 11/20/2008).
MDRNA Data Shows UsiRNAs Capable of Target Gene Silencing In Vivo
MDRNA said this week that it has presented data showing that its so-called UsiRNAs were capable of triggering significant inhibition of a target gene, apolipoprotein B, in a rodent model.
The data were presented at Asia TIDES Oligonucleotide and Peptide Technology and Product Development Conference in Tokyo, MDRNA said.
UsiRNAs are duplex siRNAs that are modified with non-nucleotide acyclic monomers, called unlocked nucleobase analogs, in which the bond between two adjacent carbon atoms of ribose is removed, according to the company.
"Placement of UNA within UsiRNA minimizes the potential for off-target effects by the guide strand, as well as undesired activity of the passenger strand," MDRNA said. "Further, the change in sugar structure renders this unlocked nucleobase analog conformationally flexible," which allows the oligo to avoid cytokine induction and provides protection from nuclease degradation.