Leading RNA interference (RNAi) therapeutics company, Silence Therapeutics plc, has entered a collaboration agreement with Mirna Therapeutics Inc. to assess the delivery capabilities of Silence's proprietary AtuPLEX and DBTC delivery systems for Mirna's novel microRNAs.

Under the terms of the agreement, Mirna will provide Silence with specific miRNA sequences, which Silence will formulate with its AtuPLEX and DBTC delivery systems in order to develop multiple candidate drugs.  Mirna will undertake in vitro and in vivo studies of the candidate drugs developed under the agreement and select lead candidates for further evaluation. Financial terms of the deal were not disclosed.

Thomas Christély, chief executive officer of Silence Therapeutics, said: “We are delighted to be collaborating with Mirna. This is our second collaboration exploring the use of Silence's delivery technologies to deliver microRNAs. However, it is Silence's first collaboration involving our new DBTC liver delivery system. Whilst internally we remain focused on the delivery of our siRNA therapies, we continue to look to broaden the potential value of our delivery systems by partnering them with other companies for use in multiple applications. Functional delivery of effective doses into target cells is one of the greatest challenges facing most nucleic acid therapies. With our delivery systems AtuPLEX, DACC and DBTC, Silence has an increasing range of delivery options to help overcome these challenges.”

Paul Lammers, MD, president and CEO of miRNA Therapeutics, said: “We are very interested to be working with Silence Therapeutics on the delivery of our miRNAs, as Silence has clearly been shown to be at the forefront of efficient and safe delivery of siRNAs and miRNAs, a process critical to the ultimate success of what promises to be a new and exciting class of targeted cancer therapeutics. Mirna has developed a strong intellectual property position in the therapeutic use of miRNAs in cancer, and has established a broad pipeline of key tumour suppressor miRNAs as potential new targeted therapeutic candidates against both solid and haematological cancers. An efficient delivery technology that provides for systemic delivery of therapeutically effective dose-levels of these miRNAs to their intended targets is a key element in their potential success in the clinic.”

Silence's proprietary lipid delivery technology AtuPLEX has demonstrated the broad systemic delivery to the vascular endothelium. Formulations generated with the AtuPLEX technology can be lyophilized (freeze dried) significantly improving stability, shipping and handling.

Silence is currently conducting a phase I trial with Atu027 which is based on AtuPLEX in patients with advanced solid cancer. Interim data analysis from this trial were presented at the 2011 American Society of Clinical Oncology conference and showed that Atu027 is safe and well tolerated and provided broad support for AtuPLEX as an effective siRNA delivery technology with the potential to overcome the recognized delivery challenges currently associated with RNAi therapeutics.

DBTC is the latest delivery system developed by scientists at Silence and allows functional targeted delivery to the liver. Unlike Silence's established delivery technologies, DBTC is a novel lipid-based formulation that functionally delivers to liver endothelial cells, hepatocytes and to other cell types of the liver. As with AtuPLEX, DBTC can be lyophilized.

Silence Therapeutics is a leading biotechnology company dedicated to the discovery, development and delivery of targeted, systemic RNA interference (RNAi) therapeutics for the treatment of serious diseases.

Mirna Therapeutics is a biotechnology company focused on the development and commercialization of microRNA (miRNA) therapeutics.

miRNAs are approximately 20-25 nucleotides long and affect gene expression by interacting with messenger RNAs. Unlike siRNAs, miRNAs are encoded in the human genome and are used as natural regulators of global gene expression. More than 1,400 miRNAs are encoded in the human genome and comprise approximately 2% of all mammalian genes. Since each miRNA appears to regulate the expression of tens to hundreds of different genes, miRNAs can function as "master-switches," efficiently regulating and coordinating multiple cellular pathways and processes. By coordinating the expression of multiple genes, miRNAs are responsible for guiding proper embryonic development, immunity, inflammation, as well as cellular growth and proliferation. Misregulation of miRNAs appears to play a fundamental role in many cancers and replacement of down regulated miRNAs in tumor cells results in a positive therapeutic response.