SR Pharma Develops One-Step Reconstitution for Lyophilized siRNA Drugs

RNAi therapeutics company SR Pharma plc (London, UK, www.srpharma.com)has developed a process that allows its proprietary liposomal-basedsiRNA formulations, "AtuRNAi" drugs, to be stored at room temperature andreconstituted in one step.

Previously, the multistep process required the AtuRNAi and theliposomal components of the AtuRNAi drugs to be separately lyophilizedand reconstituted before being combined. The company's technology nowenables siRNA drugs preformulated as liposomal nanoparticles to befreeze-dried as a dry-powder formulation and then reconstituted withwater just before patient administration as an injectable.

The company's subsidiary, Atugen (Berlin, Germany, www.atugen.com),developed AtuRNAi as chemically modified, stabilized siRNA molecules. Itdiffers from conventional siRNA in that it contains only naturallyoccurring RNA building blocks and no DNA, its size consists of 19 basepairs (as opposed to 21-23 base pairs in conventional siRNA), it has alonger half life in body fluids, and it is designed for fastersynthesis and increased yield. The company also reports AtuRNAi'sshorter oligonucleotide length results in more cost-efficientmanufacturing.

According to Klaus Giese, chief scientific officer of SR Pharma, "A dry-powder formulationextends the shelf life and simplifies the distribution chain . . . We willbe applying this technology to the manufacture of our products as wetake our siRNA drugs forward towards the clinic."