In a bid to advance the development of an RNAi-based treatment for Huntington's disease, Sirna Therapeutics announced this week that it has formed a collaboration with gene therapy firm Targeted Genetics.
Through the deal, Sirna will be able to apply Targeted Genetics adeno-associated virus vector-based delivery technology to its own siRNA-based drug candidates in order to overcome the challenges of delivery.
Sirna's interest in Huntington's disease extends back at least to early 2004, when RNAi News reported that the company had hired as a full-time consultant University of Iowa researcher Beverly Davidson, who is working on an RNAi-based treatment for the disease (see RNAi News, 2/27/2004). A few months later, Sirna announced that it was exploring the disease in collaboration with Davidson, and that it had in-licensed patents from the University of Iowa Research Foundation covering neurological disease targets using RNAi technology, including those relating to Huntington's disease (see RNAi News, 6/11/2004).
Huntington's disease is a member of a class of disorders known as polyglutamine diseases and is caused by the expansion of a CAG repeat in exon 1 of the gene huntingtin. In August 2004, Davidson published data demonstrating that recombinant AAV vectors expressing short-hairpin RNAs were able to inhibit gene expression in an animal model of spinocerebellar ataxia type 1, another polyglutamine disease.
Based on the success of Davidson's work, Sirna formally announced last October that it would move forward with its Huntington's disease program. As with just about every RNAi-based drug in development, however, delivery continues to be a problem. As such, Sirna has sought the expertise of Targeted Genetics.
Targeted Genetics is currently applying its gene-therapy technology to the development of gene therapies for cystic fibrosis, rheumatoid arthritis, and HIV. But the company also sees potential for the technology in therapeutic areas beyond gene replacement.
H. Stewart Parker, president and CEO of Targeted Genetics, told RNAi News this week that although Targeted Genetics has not conducted any formal research and development in the RNAi field before, she said the company has done preclinical proof-of-concept tests looking at the ability of its AAV vectors to deliver RNAi molecules, as well as antibodies and antisense molecules.
After discussions with various RNAi companies, she said, Targeted Genetics struck its deal with Sirna.
Through the collaboration we are gaining access to Targeted Genetics' extensive capabilities in the development, clinical testing, and manufacture of AAV-based products, Sirna President and CEO Howard Robin said in a statement announcing the collaboration.
Under the terms of the deal, Sirna and Targeted Genetics will share development costs, as well as revenue from partnering and sales of products developed through the deal. Additionally, the companies will share co-promotion rights for resulting products.
Parker noted that although the Sirna arrangement is exclusive in the area of RNAi-based treatments for Huntington's disease, her company is free to pursue RNAi partnerships with other companies in other disease areas.
At the JPMorgan Annual Healthcare Conference held in San Francisco this week, Robin said that Sirna expects to have an investigational new drug application for an RNAi-based Huntington's disease treatment ready by the first quarter of 2006, with a phase I trial to begin shortly thereafter.
Phase II development on the drug is anticipated to begin in 2007, with a phase III trial starting in 2008.
Parker told RNAi News that both Targeted Genetics and Sirna anticipate bringing a third party, such as a large pharmaceutical company, into their Huntington's disease drug partnership as a commercial partner some time in the future.
At the JPMorgan conference, Robin also presented timelines for Sirna's other drug-development programs:
The company's age-related macular degeneration drug Sirna-027, which entered phase I testing late last year (see RNAi News, 11/26/2004), is expected to reach phase II in 2005 and phase III in 2007. Robin noted that data from the phase I study is expected to be ready in the third quarter of this year.
Sirna's hair-removal drug program, which is being conducted through a new company subsidiary called Sirna Dermatology (see RNAi News, 12/10/2004), is expected to reach the IND/phase I stage in the second quarter of 2006. Phase II testing of a drug candidate is slated for some time in 2007, and phase III studies are expected in 2009.
Last week, Sirna reported that it had expanded its drug-development portfolio to include asthma and diabetes (see RNAi News, 1/7/2005). Robin noted in his JPMorgan conference presentation that an RNAi- based drug candidate for asthma is expected to reach phase I testing in the fourth quarter of 2006, phase II trials in 2008, and phase III studies in 2009.
An experimental siRNA therapy for diabetes is expected to reach phase I in the second quarter of 2007. Phase II studies are anticipated for sometime in 2008, and phase III trials in 2010.