MDRNA To Present Data On Tumor Reduction At Cancer Therapy Conference

Main Category: Cancer / Oncology
Article Date: 29 Oct 2009 - 23:00 PDT

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MDRNA, Inc. (NASDAQ: MRNA), a leading RNAi-based drug discovery and development company, today announced the presentation of data related to its RNAi oncology programs at the 24th Annual Meeting of the International Society for Biological Therapy of Cancer, taking place October 28-31, 2009 at the Gaylord National Hotel and Convention Center in Washington, D.C. Shaguna Seth, Ph.D., Director of Discovery Research and Pharmaceutical Development, will present data detailing an emerging approach to cancer therapy by harnessing RNA interference to silence aberrant expression of genes linked to cancer.

"Development of Novel RNAi-based Therapeutics Targeting Survivin for Treatment of Liver and Bladder Cancer," presented by Dr. Seth, describes anti-tumor activity of a proprietary siRNA construct, termed UsiRNA, targeting survivin, a key protein in the progression of cancer, in an orthotopic model of liver cancer and an orthotopic model of bladder cancer. The UsiRNA was delivered with the Company's proprietary DiLA2 liposome formulations via systemic (liver cancer) and local (bladder cancer) administration.

In liver cancer, treatment with survivin UsiRNA in DiLA2 liposomes resulted in >60% knockdown of survivin mRNA during twice weekly dosing over a three-week period, and knockdown persisted for an additional three weeks after the last dose. High tumor burden in the vehicle and UsiRNA scrambled control groups prompted study termination at seven weeks, at which time there was a 65% decrease in tumor weights in the survivin UsiRNA-treated group, compared to negative controls. This level of difference was similar to Avastin® (bevacizumab)-treated mice which served as the positive control. Potent anti-cancer activity was also demonstrated for bladder cancer. Twice weekly dosing for two weeks with survivin UsiRNA in DiLA2 liposomes demonstrated an approximately 70% reduction in survivin mRNA during the dosing period and a duration of effect at 11 days post final dose of up to 90% reduction in survivin mRNA. There was a dose-dependent decrease in bioluminescence of up to 90% in UsiRNA-treated mice, indicating significant reduction in tumor volume compared to vehicle and scrambled UsiRNA controls. In both models, the mechanism was confirmed to be via RNA interference, as noted by identification of specific fragments generated by RISC cleavage of survivin mRNA.

"We continue to be encouraged by the progress of our oncology programs," said Dr. Barry Polisky, Chief Scientific Officer of MDRNA. "As we expand our efforts, we expect to explore RNAi mediated knockdown of further potential cancer targets in both disease models. In addition, we plan to assess the impact of combination approaches such as UsiRNAs targeting two separate gene targets as well as the combination of a UsiRNA and a conventional therapy."

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MDRNA, Inc.