Nucleonics granted two RNAi patents by IP Australia

RNA-interference therapeutics company Nucleonics has announced that IP Australia has granted the Medical College of Georgia Research Institute (MCGRI) two patents covering an RNAi gene-silencing technique. Nucleonics is a licensee to both patents.

Nucleonics' CEO Robert Towarnicki described the patents as "very broad, as we expected when we licensed them.

"Australian companies are working in vertebrate cellular systems, this patent covers that," he said.

Asked whether the new patents would apply to human gene-therapy applications being developed by local RNAi company Benitec (ASX:BLT), Towarnicki said, "We think they're going to need a licence."

The first patent, titled "Composition and Method for In Vivo and In Vitro Attenuation of Gene Expression Using Double-Stranded RNA" (Australian Patent No. 776150), covers the use of synthetically produced as well as DNA-encoded double-stranded RNA in vertebrates for attenuation of gene expression by RNAi. The claims cover the use of RNAi in vertebrate cell culture and animals and RNAi-based human therapeutics.

The second patent, Innovation Patent No. 2004100997, titled "Composition and Method for In Vivo and In Vitro Attenuation of Gene Expression Using Double-Stranded RNA" (AU), contains similar claims. It includes "a method for treating or preventing disease or infection in a vertebrate comprising: identifying a target gene, wherein expression of the target gene is associated with the disease or infection; and attenuating the expression of the target gene".

But Benitec's in-house patent counsel, Sally Brashears, said today that, although the company was still called Benitec Australia, all RNAi therapeutics research is now run from Benitec's US laboratories in Sunnyvale, California, formerly owned by Avocel, before it was acquired by Benitec last year.

"We no longer have any presence in Australia as far as lab work is concerned," Brashears said. "It might be an issue if and when we want to sell our RNAi therapeutics in Australia.

"But Nucleonics is near and dear to our heart, so we will look over it, as we look over any issued IP in the RNAi space."

While Brashears agreed that the patents' claims were very broad, she noted that they are narrowly based on a particular method of purifying RNA molecules whose coding sequences are to be used to induce RNAi-mediated gene silence.

The technique relates to the use of phenol chloroform as a solvent to purify RNA - a technique presumably specified by the US originators of the MCGRI's intellectual property, Professor Andy Fire and Professor Craig Mello, of the Carnegie Institute.

According to Brashears, the method has been rendered obsolecent by new techniques that no longer require phenol chloroform - such as the purification-column system sold by global RNAi technology developer Qiagen.

Brashears said the technique was still being used in laboratory research, but not in any real-world application of RNAi technology.

"It's really not terribly limiting. In fact, it's probably irrelevant, because all you have to do to get around the [MCGRI] patent is to avoid using phenol chloroform."

Late last year IP Australia re-examined the CSIRO-Benitec RNAi patents at Nucleonics' request, and ruled that documents submitted as evidence of prior art and lack of novelty would invalidate the patents.

Benitec's acting CEO, Sarah Cunningham, said that her company had responded to the ruling within the 60-day period allowed, but had yet to receive a response. Meanwhile, Nucleonics has sought a similar review from the US Patent Office, and has lodged observations asking the European and Polish patent offices not to grant the patents in those jurisdictions.

Towarnicki said was the US Patent Office review process could take as long as six months. It differed from the Australian process, in that it gave Benitec and CSIRO 60 days to respond before any decision was made. He did not believe that Benitec and CSIRO had done so.

"We believe firmly we have a strong case in the US for getting that [Benitec/CSIRO] patent invalidated, either through the courts or the US Patent Office - it's a matter of whatever timing gets us there first.

"We don't expect to lose. But having said that, we've always been of the mindset that we don't have to be the only RNAi company in the world.

"We don't want to be obstructionist. There's room for many players, and if there were reasonable ways to resolve the dispute, we'd be prepared to do it.

"But we've not had a reasonable discussion [with Benitec] yet."

Benitec's Bashears said, "My job is likely to become much more interesting over the next couple of years."