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Arrowhead Preps Phase I siRNA Drug Data for Publication, Raises $3.2M in Private Placement


By Doug Macron

Arrowhead Research said last week that its subsidiary Calando Pharmaceuticals continues to advance its siRNA-based cancer drug CALAA-01 through a phase I study and that certain data from the trial have been prepared for publication in a yet-to-be-named peer-reviewed journal.

According to Arrowhead President and CEO Christopher Anzalone, the data are expected to bolster the company's efforts to either divest or find a partner for Calando — a longstanding corporate goal — but he said that specific details about the clinical results were not yet being disclosed.

Arrowhead also last week reported its fiscal fourth-quarter financial results, posting a sharp drop in losses on significantly lower operating expenses, and announced that it had raised roughly $3.2 million through the private placement of stock and warrants.

Discussing CALAA-01, Anzalone said that "we believe we have reached a pivotal point in Calando's siRNA clinical trial, [which] is critical when determining [the company's] near-term value and proximity to a liquidity event" such as a merger or acquisition. He made the remark during a conference call held last week to discuss Arrowhead's financial results.

CALAA-01 is a non-modified siRNA targeting the M2 subunit of ribonucleotide reductase and is delivered using Calando's so-called Rondel delivery system. In 2008, the drug moved into a phase I study, becoming the first formulated siRNA therapeutic to be tested in humans.

The study is an open-label, dose-escalating trial in patients with non-resectable or metastatic solid tumors. Though its primary endpoints are safety and tolerability, the trial is also designed to evaluate pharmacokinetics and tumor response.

"While we have not yet finished the trial, we have seen [that] CALAA-01 is very well tolerated and [we] continue to search for the maximum tolerated dose," Anzalone during the call. "Importantly, at the current dose range, we are beginning to see some very encouraging clinical activity and we believe we may be significantly below the" maximum tolerated dose.

"A manuscript describing some of these data has been prepared for possible publication," he added, although he cautioned that it is unclear when and where the paper may actually publish. Still, "I believe our dataset will ultimately bolster the value of Calando's drug candidates and proprietary RNAi drug-delivery system."

Anzalone declined to provide any details about the data when asked during the conference call. In a statement, he said that the company would discuss the data upon its publication.

Fiscal Fourth and Financing

For the three-month period ended Sept. 30, Arrowhead's net loss dropped to $3.5 million, or $0.06 per share, from $8.7 million, or $0.22 per share, in the same period a year earlier.

Operating costs in the fiscal fourth quarter fell 68 percent to $3.7 million from $11.5 million the year before, reflecting a broad cost-cutting initiative launched at the beginning of the year that included narrowing Calando's pipeline to just CALAA-01 (see RNAi News, 11/5/2009).

At the end of the quarter, Arrowhead had cash and cash equivalents totaling $2 million. However, during the fiscal first quarter of 2010, the company closed the private placement of roughly 5 million units consisting of one newly issued share and a warrant to purchase an additional share, raising $3.2 million.

"The current financing puts us on more solid footing to advance our strategic initiatives as we move through fiscal 2010 … [and] we expect this financing to provide sufficient capital to cover operations through fiscal 2010," Anzalone said during the conference call.