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Is Cancer Too Difficult For Sirna to Tackle On Its Own? Executives Disagree

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As the two top executives at Sirna Therapeutics travel the country meeting with potential collaborators and presenting the company’s technology at various conferences, it appears that they are not quite on the same page.

Early last week, Sirna COO Nassim Usman told an audience at the Strategic Research Institute’s siRNA in Drug Discovery and Development conference in San Diego that the company had decided against pursuing oncology as an in-house research and development program, noting that the area was simply “too difficult” for the firm to pursue on its own.

The statement, along with ones made later in an interview with RNAi News, directly contradicted those made by Sirna president and CEO Howard Robin.

Sirna officials have long been talking about adding a third name to the list of diseases for which the firm is developing RNAi therapies. In September of last year, Robin said at a financial conference in New York that Sirna was set on reaching a decision some time in 2004 (see RNAi News, 9/26/2003).

Then, in January this year, Robin told an audience of investors and analysts at the JP Morgan Healthcare Conference that a cancer program might be joining the company’s ongoing R&D efforts in age-related macular degeneration and hepatitis C (see RNAi News, 1/23/2004).

Although he did not commit fully to oncology in his presentation at the JP Morgan event, he told RNAi News at the time that the company was “working on whether [the new focus] might be in the area of CNS or the area of oncology or anti-inflammatory [diseases],” adding that “oncology is a likely candidate.”

Several days after his presentation in San Diego, Usman spoke with RNAi News about Sirna’s decision not to pursue cancer on its own, stating “we had never intended to develop an oncology product alone,” and that Robin’s comments earlier in the year most likely referenced the company’s oncology collaboration with Eli Lilly (see RNAi News, 1/30/2004). Usman added that the research the company has conducted on its own in cancer, including ongoing work with the Cleveland Clinic, is only proof-of-concept work done to demonstrate to possible collaborators that Sirna’s technology can be applied to the disease.

“We’ve had so much interest from the oncology divisions of large pharmaceutical companies,” Usman said. “Oncology is a very important area for siRNA, but Sirna itself [doesn’t] have the expertise and means to fully develop” a cancer drug.

Usman noted that while Sirna has the capabilities to generate siRNA drug candidates and test them in animal models, it lacks the resources to bring a potential cancer drug through expensive clinical trials.

“The endpoints [in cancer drug studies] are not always very easy to see early on,” compared with the endpoints in trials of hepatitis C therapies, for example, Usman said. With HCV, “you can tell in phase I … whether your drug is working,” but with cancer this is rarely the case, he said.

As such, a company would be required to take an oncology drug candidate much farther through clinical development before efficacy can be determined, and the expenses related to such an endeavor are something that Sirna would prefer to bear with a partner, Usman said.

Based on Usman’s rationale, Sirna’s decision not to go ahead with cancer on its own seems a sensible one. But the questions remain: Wouldn’t Sirna have figured on the high cost of cancer drug development before it began looking into oncology as an in-house program? If it had, and Usman is correct in that the company never planned on pursuing the disease on its own, what about Robin’s earlier statements?

Speaking with RNAi News shortly after Usman’s interview, Robin flatly denied that oncology has been ruled out as a possible area of in-house drug development for Sirna. “I would never say that we wouldn’t [develop a cancer drug] on our own — there’s always the possibility of that,” he said.

Robin stressed that “for now, we’re working with Lilly and it’s likely that we’d work together with a partner in oncology,” but added that it would be “an incorrect statement” to say that Sirna would not work in oncology on its own.

Robin said that he “could probably list three tumors that we could do in house,” although he declined to be specific. While it is “highly likely” that Sirna would only develop cancer drugs with a partner, at least in the near term, “I would not rule out doing it ourselves,” he said, adding that a third preclinical drug program has yet to be settled on.

In Other News

Usman also noted during the conference in San Diego that early last month Sirna had its pre-investigational new drug application meeting with the US Food and Drug Administration about its intraocularly-delivered AMD drug candidate, called Sirna-027.

He told RNAi News that the agency has approved the company’s phase I plan, that toxicology studies have begun, and that manufacturing of clinical supplies of the AMD drug candidate is set to begin in Sirna’s manufacturing facilities in the second quarter.

The company remains on track to file an IND for the AMD therapy, as well as to have selected a preclinical hepatitis C drug candidate, before the end of the year, Usman added.

Sirna also reported this week its financial results for the first quarter of 2004, posting a decline in revenues, to $318,000 from $490,000. Revenues in the quarter, noted the company, include payments stemming from the Lilly collaboration.

The company reported that its research and development spending in the first quarter rose to $5.1 million, up from $3.8 million in the first quarter 2003, in part due to an increase in expenses related to Sirna-027.

Sirna had about $29.6 million in cash, cash equivalents, and marketable securities as of March 31.

—DM