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Sirna, Refocused and With Cash in Its Pocket, Working to Get RNAi Drug in Clinic Next Year


About a year after reinventing itself as an RNAi company, Sirna Therapeutics (formerly Ribozyme Pharmaceuticals) appears to have gotten back into the swing of things.

The Boulder, Colo.-based company, which released its second-quarter financials Aug. 14, is conducting in vivo tests of its siRNA therapeutic candidates, and preparing to ask for the FDA’s approval next year to begin clinical trials of at least one siRNA drug candidate, according to company executives, setting it up to potentially be the first to test the therapeutic possibilities of the technology in humans.

Sirna remains on-track to select lead drug candidates in the two therapeutic areas it has chosen as its focus — hepatitis C and age-related macular degeneration — by year-end, and submit at least one IND by the end of 2004, said Nasseem Usman, the company’s chief scientific officer. Usman noted, however, that it is not yet clear whether the filing (if there is, in fact, only one) will be for a hepatitis C or AMD compound.

The company is planning to release this year new data demonstrating systemic efficacy of its siRNA compounds in animal models. Data on the efficacy of local delivery, he added, are already available. As it stands now, Usman said, the AMD program could be considered more advanced, given that the drug is administered locally, which greatly simplifies delivery issues.

As for Sirna’s ability to fund itself as it pursues these goals, Marvin Tancer, the company’s chief financial officer, said the company has enough cash to last it for the next two or three years with its current monthly burn rate of between $1.2 million and $1.5 million. According to its second-quarter results, the company had cash, cash equivalents, and securities for sale worth $43.8 million, as of June 30.

Meanwhile, Sirna posted a lower second quarter loss amid higher revenues from contract manufacturing, despite an increase in operating costs. The company’s revenues for the period, derived in part from contract manufacturing, came to $3 million, up from $1.6 million to $10.8 million in the year-ago quarter. Net loss for the second quarter was $7.8 million, versus $9.3 million a year ago. R&D expenses fell to $4.3 million from $7.9 million, reflecting the company’s dropping its ribozyme programs and restructuring itself to focus on RNAi alone.

Sirna’s overall operating expenses rose about $1.6 million, as the company recorded a one-time non-cash charge of $5.3 million in deferred patent costs for patents that do not directly relate to RNAi.

Company RNAissance

In its previous incarnation, the company was focused on using ribozymes to cut up RNA encoding for disease-causing proteins. While Ribozyme managed to get three drug candidates into clinical trials, none of these ever proved to be effective, and the cash-strapped company made the decision to turn its attention fully to RNAi.

And it did so rather gracefully. In 2001, the company brought in Tancer as CFO and promoted COO Howard Robin to CEO, and the next year announced that it would shelve its ribozyme programs to work on RNAi exclusively. In April this year, Ribozyme changed its name and stock ticker symbol (RNAI) to reflect its new focus, and then netted $45 million in a round of private financing — all the while touting its RNA experience and IP estate as the keys to future success.

“The problems that Ribozyme had were clinical problems with their drugs. There is some potential for RNAi to avoid the problems that were encountered in the clinic with ribozymes,” said Douglas Fambrough, Sirna board member and principal at Oxford Bioscience, which invested about $8 million in the company for a mid-teens percentage stake. “I didn’t say there were big problems with the company itself. The core scientific [team] at Sirna is very strong and the capabilities they’ve built in RNA chemistry are unparalleled.”

As for patents, Fambrough told RNAi News that “it’s so early ...that it’s hard to say anything that’s definitive about IP. What I can say is: we’re comfortable with the IP position.”

Tancer told RNAi News that Sirna has taken licenses to the fundamental Fire-Mello patents being non-exclusively licensed by the Carnegie Institution and the University of Massachusetts, and is taking a serious look at the Tuschl patent applications held by MIT. Aside from this kind of “base technology” IP, he said, Sirna has, as a result of its earlier work with RNA, 30 issued patents “in the areas of chemical stabilization, process development, and manufacturing, which make [siRNAs] real as potential therapeutics,” he said.

The company also has filed 50 patent applications covering, among other things, oligo stabilization, delivery technology, and individual drug targets in areas such as cancer and metabolic diseases, “We have identified targets, we’ve made the RNAi constructs, we’ve stabilized those constructs, we’ve knocked out the targets, and filed the IP,” Tancer said.

He noted, however, that this timeline could change if Sirna’s active pursuit of collaborations, which are part of the firm’s “strategic plan”, pays off.

“Basically, we’re looking at the larger pharma companies and the larger, more-established biotech companies” and are interested in ones with strong clinical development and commercialization capabilities that compliment siRNA.

But before any comemrcialization or clinical trials can begin, Sirna, like all companies trying to turn RNAi science into medicine, needs to overcome the drug delivery hurdle. As such, Tancer said it is also on the look out to ink an alliance with a firm that has strong drug delviery technology.

— DM


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