BioWorld International Correspondent

LONDON - Oxford BioMedica plc has taken out rights to use the RNAi gene-silencing technology invented by Nobelists Andrew Fire and Craig Mello in conjunction with the company's LentiVector viral delivery system.

The agreement opens up new avenues in Oxford BioMedica's gene therapy portfolio. Alan Kingsman, CEO, told BioWorld International the company is planning to combine the two technologies to develop treatments for infectious diseases and central nervous system disorders.

"The issue with RNAi is delivery, as was the case with ribosomes and antisense. I've no doubt that encoded RNAi is the way to go," Kingsman said.

Other companies are attempting to deliver RNAi using liposomal delivery vehicles. Although Kingsman acknowledged there have been advances in liposome technology, he said, "The fact is that viruses are millions of times more efficient than other vectors."

Liposomes often have been favored for their safety profile, but Kingsman claimed experience in using LentiVector in the clinic has dispelled any remaining safety concerns with the viral vector. "Last month, we secured regulatory approval to use LentiVector for gene delivery in the brain; ongoing trials with TroVax [Oxford BioMedica's cancer gene therapy] have raised no safety issues," said Kingsman, adding, "The balance of critical benefits [in terms of systemic delivery] now outweigh the risks."

Another company working on delivery of RNAi with a viral vector - in this case adeno-associated virus, Tacere Therapeutics Inc., of San Jose, Calif., sealed a deal with Pfizer Inc. That agreement, for TT-033, a treatment for hepatitis C that is some 18 months away from the clinic, attracted an undisclosed up-front payment and is worth up to $145 million in milestones, plus royalties.

Oxford BioMedica will give further details of its proposed RNAi programs at an R&D review in March. Kingsman said RNAi delivered with LentiVector is something the company has worked on behind the scenes for a year and has published a couple of illustrative papers on the subject.

Over the same time, the Oxford, UK-based company has agreed to a number of small research deals on LentiVector for RNAi delivery with academic and industrial partners. Kingsman said he expects some of those to become commercial agreements. "We aren't doing this to develop an RNAi delivery platform for other people; our focus is on generating products for our own portfolio."

Under the terms of the license, Oxford BioMedica will make up-front, milestone and royalty payments. The rights run concurrently with those of existing licensees. The owners of the RNAi technology, the Carnegie Institution of Washington and the University of Massachusetts Medical School, have agreed to subscribe to 2.4 million new Oxford BioMedica shares at discount.

It may be unusual for academic partners to take equity stakes in licensee companies, but Oxford BioMedica has made this a feature of a number of deals. "It's a way of cementing the relationship with the organization that gives them a stake in the upside," Kingsman said. "As a small company, we can't necessarily pay huge amounts of cash up front."