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At UBS Conference, Three RNAi Chiefs Talk Drugs, Alliances, Spin-Outs, and Baby Steps


The chief executives of three RNAi drug developers — Sirna Therapeutics, CytRx, and Nastech Pharmaceutical — presented this week at the UBS Global Specialty Pharmaceuticals Conference in New York, giving a few new details about their efforts with the gene-silencing technology.

For Sirna, the only pure-play RNAi firm to present at the event, the talk was all RNAi, with pipeline updates and some insights into how the company plans to structure its future corporate collaborations.

For CytRx, which is continuing with its move away from RNAi drugs, the presentation focused primarily on the company's small-molecule drug candidates, and reiterated plans to spin out its RNAi drug operations. Once again, details on how CytRx plans to fund the move were not disclosed.

Meanwhile, Nastech split its time between its more mature small-molecule drug programs and its relatively recent foray into the world of RNAi therapeutics.


At the conference, Sirna CEO Howard Robin broke down his company's pipeline, noting that it remains on track to selecting a clinical candidate in Huntington's disease before the end of 2006; that a phase II trial of its age-related macular degeneration drug Sirna-027, which was licensed to Allergan last year (see RNAi News, 10/7/2005), is set to begin in the second half of the year; and that a phase I study of an RNAi-based drug for permanent hair removal is set to start in the first quarter of next year.

Sirna doesn't "want to work with any one company across broad therapeutic areas."

Robin also gave an updated timeline for Sirna-034, the company's hepatitis C therapy, stating that a clinical candidate has been selected, and that the US Food and Drug Administration has accepted a pre-investigational new drug application package for the drug. With this milestone reached, "we expect to have an IND filed by the fourth quarter of this year — hopefully October," he said.

Interestingly, while cluing investors in on the hepatitis C program, Robin said that the drug incorporates a home-grown nanoparticle technology, the ownership of which is currently the subject of litigation.

"The nanoparticles are spherical in shape, [and] the siRNAs are a part of the nanoparticle," Robin explained. "When the nanoparticle gets into the endosome it goes through a pH shift. As the pH drops, the nanoparticle goes from a sphere to a cylinder and releases the siRNA from the matrix of the nanoparticle into the cytoplasm of the cell. That's something we invented."

According to a lawsuit filed by Protiva, the technology was invented by its scientists and stolen by Sirna after details of the technology were revealed through an alliance between the companies (see RNAi News, 3/2/2006 and 3/30/2006). In its own lawsuit, Sirna has alleged that Protiva never had the rights to its nanoparticle technology, and the technology being used with Sirna-034 is novel.

Robin made no mention of the dispute during his presentation.

While speaking at the conference, Robin also reaffirmed Sirna's expectation that it will sign at least one more corporate partnership during 2006, building upon its recent deal with GlaxoSmithKline to discover, develop, and commercialize RNAi-based treatments for respiratory diseases (see RNAi News, 4/6/2006).

He also provided some insight about how Sirna plans to structure any future collaborations, stating that the company strives to "find the right mix between collaborations and taking things into the clinic ourselves."

According to Robin, "we [don't] want to work with any one company across broad therapeutic areas. I can't imagine that we would license out something such as oncology — [It's way] too broad [with] hundreds of different diseases," he said.

The company is "very selective" and would consider deals in narrow therapeutic areas, such as the respiratory field, "which is fairly narrow and encompasses only two or three or four diseases at most," he noted. Similarly, "an ocular therapeutic collaboration makes sense."

On the other side of the coin are "target-focused deals," that are limited to a particular target in a particular indication. "You'll see one or the other in the future, but I don't think you'll see from Sirna Therapeutics broad therapeutic area collaborations such as something in oncology where there are too many different diseases to collaborate with only one company."


As first reported in RNAi News, CytRx has been planning to spin out its RNAi therapeutics operations into a separate company since at least late last year (see RNAi News, 11/1//2005). By early this year, the company publicly disclosed its intention, calling it a way to increase the RNAi business' overall valuation (see RNAi News, 2/2/2006).

"In order to really value our RNAi business the way we think it should be valued, we're setting up a separate subsidiary focused totally on RNAi therapeutics so that we [can] develop drugs. That's something we're working on now, [but] it's subject to financing."

At the UBS conference, CytRx President and CEO Steven Kriegsman dedicated the majority of his presentation to the company's small-molecule drugs and DNA-based HIV vaccine, but noted that it is still "very active in RNAi with programs in obesity, type II diabetes, in [amyotrophic lateral sclerosis], as well as [cytomegalovirus] retinitis."

Kriegsman highlighted the company's use of RNAi for target discovery — something that just about every pharmaceutical firm does — but stressed that RNAi therapeutics remains "an exciting area and [something] we're putting a lot of emphasis on."

However, he said that spinning out the business remains a "high priority."

"In order to really value our RNAi business the way we think it should be valued, we're setting up a separate subsidiary focused totally on RNAi therapeutics so that we [can] develop drugs," he said, echoing past remarks. "That's something we're working on now, [but] it's subject to financing."

CytRx has long said that its ability to spin out its RNAi drugs operations will require a level of financing that the company currently does not have access to. Earlier this month, in a filing with the US Securities and Exchange Commission, CytRx said that the spinout is expected to occur "in the coming months," but added that it has neither raised the money to do so nor established "commitments or arrangements for any financing."

During his UBS presentation, Kreigsman did not address the company's financial situation or provide details on how it plans to find the money to fund the spin out.


As head of one of the newest companies to enter the RNAi therapeutics space, Nastech President and CEO Steven Quay divided his presentation between keeping the audience updated on the company's non-RNAi pipeline programs and giving some background on how it began working with the gene-silencing technology.

"RNAi therapeutics, after gene cloning and monoclonal antibodies, may be the third most important technology to come out of the biotech industry since its inception in the 70s," he said. "The key challenge is the delivery solution … [and] over three years ago Nastech began the process of focusing on delivery."

According to Quay, Nastech researchers studying paracellular drug delivery discovered that the company's delivery technology could be used to carry oligonucleotides, namely siRNAs, into cells.

"With this observation … [Nastech] became the first company to demonstrate successful in vivo delivery with an RNAi therapeutic," he said "That therapeutic is against TNF-alpha … for rheumatoid arthritis."

Late last year, Nastech presented data at the American College of Rheumatology's annual scientific meeting in San Diego showing that an siRNA, administered both intravenously and subcutaneously using company technology, could be used to stop the production of human TNF-alpha in mouse models of RA (see RNAi News, 11/25/2005).

Quay did not provide new details during his presentation about the status of the RA program, or of Nastech's new RNAi flu program, which it acquired from Galenea (see RNAi News, 2/23/2006). However, Quay told RNAi News last month that the company expects to file an IND for a flu drug near the end of the year (see RNAi News, 3/2/2006). The company has not provided any timelines for the development of the RA therapy.

— Doug Macron ([email protected])

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