CSIRO, Benitec strengthen RNAi patent positions

The legal mists are lifting from Black Mountain in Canberra, and Mountain View in California, clarifying the ownership of key patents on RNA interference (RNAi) gene silencing technology.

CSIRO and gene therapy company Benitec (ASX:BLT) have successfully weathered an Australian Patent Office re-examination of two jointly held patents on DNA-delivered RNA-interference technology (RNAi), requested by Pennsylvanian gene therapy company Nucleonics.

RNAi technology has been hailed as the most important tool for exploring and manipulating gene function to emerge in two decades.

The Australian Patent Office has also granted a 1998 patent application to CSIRO for its 'hairpin' RNAi gene-knockdown technology, used for exploring gene function in plants, animals and humans. CSIRO has also been granted similar patents in China and New Zealand.

Dr Rob de Feyter, intellectual property manager of CSIRO Plant Industry, which developed hairpin technology, said CSIRO had also been successful in opposing a rival Australian patent sought by Syngenta. The global agbiotech company has since withdrawn its application.

De Feyter said resolution of the cases 'provides greater clarity and confidence for users of RNAi', and said CSIRO would continue to provide access to the technology through research and commercial licences.

CSIRO is using the technology itself to explore and manipulate gene function in crop plants and livestock animals.

Benitec CEO Sarah Cunningham said the two CSIRO-Benitec patents had gone through the entire reexamination process, with "very slight" amendments, that did not narrow the scope of the claims.

She said the patents could now be regarded as "Teflon-coated, if not bulletproof".

Nucleonics has also asked the US Patent Office to re-examine the same two CSIRO-Benitec patents.

The US office has yet to report on the re-examination, but Cunningham said Nucleonics is using the same documentation it submitted for its unsuccessful re-examination by the Australian Patent Office.

The US re-examination, and a similar, unresolved 'third party observation' lodged by Nucleonics with the European Patent Office, remain Nucleonics' best hope of maintaining its own IP position, which is based on RNAi IP licensed from the Carnegie Institute of Washington.

The US District Court of Delaware recently dismissed, without prejudice, Benitec's patent-infringement case against Nucleonics, after the Pennsylvania company argued that it currently has no product based on the CSIRO-Benitec patents, and may never have one. That decision gives Benitec the right to sue Nucleonics again, should it consider that Nucleonics is infringing its patents.

But the recent developments appear to leave Nucleonics in a difficult situation -- it has not taken a licence that would allow it to use the Australian patents, yet it has raised $42.8 million from investors, in three tranches, on the assumption that it would have freedom to operate in the US.

In documents submitted to the court, Nucleonics stated that the second tranche was actually contingent on it having freedom to operate in the US, using the Carnegie Institute patent.

Benitec in Sigma deal

Benitec announced today that it has signed two major agreements with Sigma-Aldrich, a major international producer of biochemical reagents and kits for bioscience research.

Under their agreements, Sigma has paid Benitec US$4.5 million. Of this figure, $2 million represents a equity stake for Sigma in Benitec.

Cunningham said the agreements further validated the impact of RNAi on basic and applied life-science research and its enormous potential for traditional drug discovery. "More importantly, they underscore Benitec's position in the RNAi arena, and our strong, proprietary patent portfolio," she said.

Benitec has retained all existing rights to human therapeutics and diagnostics, including the ability to enter into commercialisation and drug discovery agreements with commercial partners.

The agreements give Sigma-Aldrich access to the non-human applications of RNAi technology, but not for plant science applications.

According to CSIRO's de Feyter, the research agency has now released its proprietary RNAi vectors to more than 2000 research laboratories around the world -- mainly in academia -- for non-commercial research. It is also releasing its more advanced Hellsgate RNAi vectors to selected customers.

De Feyter said CSIRO sees a major market for its RNAi technology in China, which has already granted patents, and India, where its patents are lodged, but not yet granted.