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RXi Remains 'Committed and Focused' on RNAi Despite Broadened Focus


By Doug Macron

Despite having expanded its focus beyond RNAi through a proposed acquisition of peptide-based immunotherapy firm Apthera, RXi Pharmaceuticals remains committed to the gene-silencing technology, the company's new president and CEO said this week.

At the same time, the merged company will be in a position to explore combining each of the firms' respective technologies, in part building off an early-stage collaboration between RXi and Generex subsidiary Antigen Express on cancer immunotherapeutics, he noted.

Last week, RXi announced that it was acquiring Apthera for roughly $7.2 million in stock, plus future contingent payments, in part to acquire the peptide shop's breast cancer immunotherapy NeuVax, which is expected to enter phase III testing in the first half of next year (GSN 3/31/2011).

According to RXi President and CEO Mark Ahn, who was an RXi board member and replaced former CEO Noah Beerman last month, the deal was part of an “effort to diversify the company” into the cancer vaccines space, where it already had gained some insights through the Antigen Express collaboration.

“About six months ago, [RXi began] to look at licensing, acquisition, or merger opportunities we could use to leverage what we knew how to do … to see if we could … progress to a development company, which is, after all, what investors appropriately demand,” he told Gene Silencing News this week. “Like every company that does basic research, we needed to figure out how to successfully make that transition,” and ultimately determined that the Apthera acquisition would accelerate the process.

Although the transaction means that RXi is no longer a pure-play RNAi firm, Ahn stressed that the company remains “completely committed” to the technology.

“We're sending every signal we possibly can that we're in the RNAi business,” he said. “We remain committed and focused on maintaining our core capabilities.”

That said, “we can't do everything,” Ahn said. As such, the new RXi has trimmed its research and development efforts to focus on NeuVax and RXI-109, an RNAi-based dermal anti-scarring candidate slated to enter phase I testing in the first half of 2012. He noted that RXi is in a position to meet both goals without a partner.

“We have multiple [RNAi] constructs and have demonstrated promising in vitro and in vivo activity … [but] we now need to make the hard choices, making a preferential bet on our best leads and bringing them to the clinic,” he explained. “That requires resource allocation between continuing to do basic research and leveraging the platforms we already have into the clinic.”

As a result, some of the company's other in-house programs, namely its earlier-stage RNAi ones, have been put on hold. However, Ahn said that development continues on an RNAi-based treatment for retinal diseases, although he declined to confirm whether the company still expects to select a lead candidate in this area before the end of this year as previously guided (GSN 9/16/2010).

He added that work on all partnered programs remains ongoing, as well. These include an arrangement with Eyegate Pharma to develop ocular delivery approaches for RNAi agents (GSN 9/23/2010); a deal with Royal Philips Electronics to explore ultrasound-guided RNAi drugs (GSN 6/10/2010); separate collaborations with Miragen Therapeutics and Mirna Therapeutics to use its RNAi technology to create microRNA mimics (GSN 4/15/2010); and a partnership with TransDerm to examine different delivery approaches for dermal delivery of RNAi molecules (GSN 4/8/2010).

Even though RXi has shifted attention away from less-developed programs for now, successes with NeuVax and RXI-109 would put the company in a position to pick them up down the road, Ahn said.

“Ironically, we need to show progress in product development to accelerate our basic research,” he said.

Ahn noted that such research potentially extends beyond pure RNAi to a merger of the technology with Apthera's immunotherapeutic know-how.

In collaboration with Antigen Express, RXi researchers showed that the self-delivering RNAi molecules could be used to silence genes key genes in hemopoietic cells. “The ability to knock down expression of certain genes in isolated hemopoietic-derived cancer cells has the potential to convert them into specific immune-stimulants,” according to RXi.

In light of these promising results, it may be possible to develop methods of using the self-delivering technology platform to administer therapeutic peptides, at which point “you've opened up a whole new window for RNAi-related technologies,” Ahn said.

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