Arrowhead Research's CEO last week struck an optimistic note about the company's drug-development efforts by stating that its Calando Pharmaceuticals subsidiary remains on track to complete a phase I study of its siRNA-based cancer drug, and partner the program before the end of the year.
Christopher Anzalone also said Calando is advancing another RNAi candidate and building its research and development infrastructure — a notable departure from events in 2009 when Arrowhead said it was halting all preclinical work and shuttering Calando's laboratory in order to trim costs.
Anzalone made the remarks during Arrowhead's fiscal second-quarter earnings conference call.
The cancer drug, CALAA-01, comprises siRNAs against the M2 subunit of ribonucleotide reductase delivered via its proprietary Rondel cyclodextrin-based polymer technology. It became the first formulated RNAi therapeutic to enter human testing in 2008.
About a year ago, Calando hit a major milestone when it published data from the ongoing phase I study in Nature, showing that CALAA-01 could knock down its intended target mRNA and protein inside a tumor through an RNA interference mechanism when delivered intravenously ( GSN 3/25/2010 ).
Earlier this year, however, Anzalone said that enrollment in the study was not proceeding as quickly as it had hoped, and that it was adding a third clinical site to “maximize the rate at which we are able to treat new patients” ( GSN 2/17/2011 ).
During last week's call, he said progress has been made on the enrollment front, and that the phase I study remains on track to wrap up by the end of the year.
He said “the number of patients we're able to biopsy” is a “big contributing factor” beyond Calando's full control, and added that “we can really only tell if we're hitting delivery-efficacy endpoints if we're able to biopsy patients [before] and during treatment.
In response to an investor's question during the conference call, Anzalone declined to provide details on the number of patients enrolled thus far in the phase I, but said that its protocols allow for up to 30.
“We are less than that, but should be in a position to talk more about this shortly when the trial is finished,” he said.
“Whatever the reasons for [this] change, we believe this shift will help us in the mid- to long term," Anzalone added. "There are only a very small number of delivery technologies in the clinic now, so our relatively advanced data and well-tolerated system will compete for partnerships with a much smaller number of other technologies than even a year ago."