By Doug Macron
Arrowhead Research’s top official this week said that the company’s Calando Pharmaceuticals subsidiary will continue developing its lead siRNA-based cancer drug CALAA-01, despite having said earlier this year that financial constraints would force it to suspend work on the drug after the completion of a phase I trial.
Still, the company said it has no plans to continue work on its other RNAi candidates, which include the preclinical siRNA-based cancer therapy CALAA-02, as it focuses on finding a partner or buyer for CALAA-01 and its Rondel RNAi delivery technology.
The disclosure from Arrowhead President and CEO Christopher Anzalone comes as part of a letter to shareholders providing an update on the status of the company and its various subsidiaries.
Within Calando, “we have ceased all pipeline [research and development] activities and are allocating resources to our remaining siRNA clinical program,” he wrote in the letter.
“We believe that focusing resources solely on the clinic is an extremely efficient use of capital and will enable us to move most rapidly and cost-effectively to an attractive partnership or sale [of the company’s RNAi technologies], assuming continued positive clinical results.”
Earlier this year, Arrowhead announced that it had closed Calando’s laboratory and shifted all its development efforts onto another of its subsidiaries. But with this week’s announcement, it appears that Arrowhead has decided to give CALAA-01 a second chance.
“Because we are at the leading edge of a field of intense interest to large pharmaceutical companies, Calando has focused its resources on continuing its siRNA clinical program with the ultimate goal of selling or partnering the platform,” Anzalone noted.
In the phase I, ascending-dose trial, CALAA-01 has been “very well tolerated thus far,” he added. “We have seen no significant drug-related toxicities and we believe we have entered the dose range where we could expect clinical activity. We have some very exciting data from the clinical trial that support our confidence that CALAA-01 and the broader Rondel platform have significant value and may be attractive acquisition targets.”
Calando CSO Thomas Schluep told RNAi News that the company has been conducting development of CALAA-01 through contract research organizations. And while the company hopes to have either partnered or out-licensed the drug before phase II work starts, he indicated that Calando would consider entering that stage of development on its own.
Such a move “would make sense from my perspective,” he said. However, “the funding is going to be the key.”
Calando was created in 2005 by Arrowhead to commercialize the Rondel technology, which was under development for small-molecule delivery by another of its subsidiaries, Insert Therapeutics (see RNAi News, 2/25/2005).
The company had some success as a pure-play RNAi shop, becoming the first company to test a formulated siRNA drug — CALAA-01 — in humans. However, a difficult economy and a need to trim costs prompted Arrowhead to merge the company with Insert under the Calando name (see RNAi News, 5/1/2008).
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Still, Arrowhead’s financial troubles persisted, and by the end of 2008 the company said it had halted work on all of Calando’s preclinical candidates, both RNAi and non-RNAi, and that it would not file any new investigational new drug applications until it could forge some sort of money-making deal (see RNAi News, 12/18/2008).
In May, the company disclosed in a filing with the US Securities and Exchange Commission that it would cease developing CALAA-01 upon the completion of its phase I trial (see RNAi News, 5/21/2009).
The following month, Arrowhead found a partner for Calando’s non-RNAi delivery technology and a related drug candidate in Cerulean Pharma (see RNAi News, 6/25/2009). Then, in August, Anzalone said during the company’s fiscal third-quarter financials conference call that the firm was “cautiously optimistic that we may be entering a period where multiple companies would have heightened interest” in partnering or licensing Calando’s RNAi assets (see RNAi News, 8/13/2009).
Such a deal has yet to materialize, however, and Schluep declined to provide a timeline for when a transaction might occur.
“I can’t really go into those details and timing is difficult to predict,” he said. “But discussions are ongoing” with interested parties.