Polyplus technology extends therapeutic potential

A new technology that improves in vivo delivery of small interfering RNAs (siRNAs) when they are associated with a cationic polymer has been developed by Polyplus-transfection, a French company specialising in research, development and commercialisation of innovative reagents for delivery of biomolecules.

This technology is based on a new class of small interfering RNAs the company has developed: "sticky siRNAs" (ssiRNAs), and involves extending the opposite ends of interfering RNAs with complementary sequences. SsiRNAs stick together end-to-end in the presence of a cationic polymer such as in vivo-jetPEI (also developed by Polyplus-transfection) and thus form complexes as stable as with genes. With this new technology, small interfering RNAs stay connected to their delivery reagent during the whole journey to the target cells, and induce the RNA interference mechanism. This innovation is applicable to therapeutic siRNAs, and a wide variety of pathologies could benefit from it such as cancers, allergies and viral diseases.

Up to now, the market for the delivery of therapeutic siRNAs has been dominated by the use of cationic lipids. Thanks to this ssiRNA technology, cationic polymers such as in vivo-jetPEI have now entered the market with clear advantages in specific areas.

"We are proud of having developed this new technology, for which we have filed a broad patent application and have registered the trademark," said Joelle Bloch, the ceo of Polyplus-transfection. "Within a few months, we have succeeded in offering our customers two major therapeutic advances: a GMP-compliant delivery reagent, in vivo-jetPEI, and a new means of delivering siRNAs associated with this reagent. Our customers have already shown a keen interest in these two developments, and ssiRNAs are starting to be tested in vivo by several academic laboratories and biotechnology companies."

The technology was outlined in an article published in Proceedings of the National Academy of Sciences of the United States of America in October 2007 under the title 'Sticky overhangs enhance siRNA-mediated gene silencing', volume 104, pages 16,050-16,055, Bolcato-Bellemin et al.