Skip to main content
Premium Trial:

Request an Annual Quote

Kylin Sees Potential for pRNA with Aptamers, But Keeps Its Eye on RNA Interference


By Doug Macron

Seeing potential for its so-called packaging RNA technology with other therapeutic RNA molecules, Kylin Therapeutics is exploring the use of the technology in conjunction with aptamers, a company official told RNAi News this week.

Still, the company's main focus remains developing pRNA for RNAi, and the work with aptamers is being conducted primarily by academic collaborators, Kylin President and CEO Eric Davis said.

"Our internal team has not spent a considerable amount of time working in [the aptamer] area," he said. Nonetheless, "the work is progressing pretty rapidly through collaborations," namely ones with members of one of the National Institutes of Health's Nanomedicine Development Centers.

Kylin was founded in 2006 to develop and commercialize pRNA, which was developed at nearby Purdue University by the company's scientific co-founder, Peixuan Guo (see RNAi News, 7/19/2007). Guo has since left Purdue and is currently a researcher at the University of Cincinnati.

According to the company, pRNA is derived from bacteriophage phi29 and can be characterized as a “gear in the DNA packaging machinery” that can be modified with therapeutic RNA.

In 2006, Guo published data describing the construction of folate-conjugated pRNA for the delivery of siRNAs to cancer cells. The next year year, he reported on how pRNA could be used to escort hammerhead ribozymes into cancer cells.

Kylin has been developing the technology as an RNAi therapeutic for cancer, and part of that work has included examining various targeting moieties, including aptamers, for targeted delivery. But "the interesting thing is that there are cases where the aptamer can have a dual effect," carrying the RNAi payload to tissues or cells of interest while also triggering a therapeutic response itself, Davis noted.

And with big pharmas' increasing appetite for RNA medicines beyond RNAi, Kylin has dedicated a portion of its resources to seeing if pRNA can have utility with therapeutic aptamers. The company is also starting to build an intellectual property position around this work; last week, it announced that the US Patent and Trademark Office will issue a patent for what Davis called its "first and broadest [patent] application" (see RNAi News, 10/8/2009).

That IP, he noted, covers the use of pRNA not only for RNAi, but also with ribozymes and aptamers.

Yet, as a small company with seven employees, Kylin is not spreading itself too thinly, and the aptamer work is being conducted mostly by collaborators at the Guo-led Phi29 DNA-Packaging Motor center, which is one of the National Institutes of Health's Nanomedicine Development Centers, he said.

In line with this approach, Kylin has also been farming out the bulk of its in vivo research to contract research organizations including Covance and Charles River Laboratories, and academic collaborators at Purdue and the University of Cincinnati, which allows it to keep its in-house efforts on refining pRNA as a platform technology, according to Davis.

[ pagebreak ]

"We found that we've been able to keep a very efficient team and actually be more productive by focusing on the [pRNA] technology and expanding the core platform" and leaving, for example, animal studies to the CROs, he said.

Also freeing up company resources has been Kylin's ability to scale up pRNA production, he added. "Now we can just purchase pRNA from a synthetic manufacturer and don't have to make it internally anymore, which was very time-consuming for us."

Thus far, data coming out of Kylin's collaborations have been promising, Davis said, but he declined to offer specific details on the company's pipeline or any projections on when these efforts may yield the firm's first drug candidate, although he noted that ovarian cancer was a key area of interest.

In addition, an academic partner in Guo's Nanomedicine Development Center is investigating pRNA in an HIV model, he said.

Davis also indicated that Kylin anticipates that its first drug program will likely only advance into the clinic with the support of an industry ally, adding that "I think some of our early work in pilot studies with some of the pharmaceutical companies … [and] a lot of our activities in the recent months will lead to a strong clinical partner.

Many big pharmas playing in the RNAi space have "tried a lot of things [through partnerships] that didn't work as advertised," he said. Kylin's technology has "some unique characteristics over other systems and [we] are still able to get some interest."