Nucleonics responds to criticisms of new patents

RNA-interference therapeutics company Nucleonics has disputed claims by Queensland rival Benitec (ASX:BTL) that two new Australian patents on RNAi technology granted to the Medical College of Georgia Research Institute are "largely irrelevant" to companies involved in medical applications of RNAi.

In an e-mail sent to Australian Biotechnology News, Nucleonics CEO Robert Towarnicki said the two patents awarded by IP Australia this week would require most companies using new RNA-purification techniques to take a licence from MCGRI, as Nucleonics has done.

Sally Brashears, patent counsel for Benitec, had said the patents were narrowly based on an outdated method of purifying RNA molecules used to induce RNAi-mediated gene silencing, that uses phenol chloroform as a solvent.

Towarnicki said the statement "totally mischaracterize" the patent claims - in fact, the use of phenol chloroform-purified RNA is specifically excluded from the claims.

In other words, researchers will not require a licence if they use phenol chloroform, but will need one if they use any other purification method, such as Qiagen's new purification-column technology.

Towarnick said the patent claim "clearly and unequivocally covers what Nucleonics refers to as eiRNA, and Benitec calls ddRNAi".

He said the claim, as published, described:

'A method for attenuating the expression of a target gene in a vertebrate cell comprising supplying the vertebrate cell with a double stranded RNA in an amount sufficient to attenuate expression of the target gene, wherein the double stranded RNA comprises a nucleotide sequence that is essentially identical to the nucleotide sequence of at least a portion of the target gene, provided that, when the double stranded RNA is supplied to the cell by delivery to the cell of double stranded RNA, the double stranded RNA if formed from single stranded RNA that is purified in the absence of phenol or chloroform.'

Towarnicki said the article's characterisation of the inventorship was "confusing and misleading - although Nucleonics is licensed under the RNAI technology of US researchers Dr Andy Fire and Dr Craig Mello, of the Carnegie Institute, the originator of the MCGRI intellectual property had been Dr Yin-Xong Li and his associates.