Benitec said last week that the US Patent and Trademark Office has again rejected certain claims within the company's core US patent, although other claims that had previously been rejected were deemed allowable.
The patent, No. 6,573,099, covers gene-expression knockdown using DNA that transcribes double-stranded RNA, and has long been the centerpiece of the company’s intellectual property estate.
The IP fell under USPTO scrutiny as part of a protracted patent-infringement battle Benitec waged with now-defunct expressed RNAi shop Nucleonics (see RNAi News, 4/2/2004).
Previously, the patent office rejected the patent’s claims based on objections related to the fundamental Fire and Mello patent held by the Carnegie Institute.
Benitec appealed the ruling, and said last week that certain of the '099 patent's claims were deemed free of prior art and allowable. However, "other claims remain rejected as obvious prior art," primarily in light of the Fire patent, the company said.
"It is the view of Benitec … that this represents progress in the re-examination, albeit slow," Benitec noted, adding that a reply to the USPTO's latest finding will be submitted no later than March 7.