NEW YORK (GenomeWeb) – Cancer drug developer Celsion last week announced that it had closed its acquisition of nucleic acid drug developer Egen, giving it a portfolio of clinical and preclinical drug candidates, as well as a lung-specific delivery technology for RNAi and microRNA therapeutics.
Under the deal, a wholly owned subsidiary of Celsion acquired the assets of Egen in exchange for $10.6 million in stock and $3.4 million in cash.
Additionally, Egen shareholders are eligible to receive up to $30.4 million upon the achievement of certain development and licensing milestones. During a conference call held to discuss the transaction, Celsion President and CEO Michael Tardugno noted that a $6 million milestone was specifically linked to TheraSilence, Egen's siRNA/miRNA delivery platform.
Specifically, that milestone would be paid upon the outlicensing of the TheraSilence technology to a partner or the advancement of a therapeutic based on the technology into clinical testing, he said, noting that Egen's lead TheraSilence candidate, the lung cancer treatment EGEN-002, is potentially 24 months away from an investigational new drug application filing.
Specific details about EGEN-002 were not disclosed, but EGEN president and CSO Khursheed Anwer, who will join Celsion as CSO, said during the call that it combines RNAi and miRNA payloads to suppress angiogenesis and trigger tumor cell death.
In 2012, Egen and collaborators at Roche published data on the use of a lipopolyamine called Staramine to deliver siRNAs into the lungs of mice.
Staramine/siRNAs nanocomplexes, modified with methoxypolyethylene glycol, were intravenously delivered into the animals, resulting in distribution to the lung, liver, spleen, and kidney, the researchers wrote in that study. However, clearance from the lung was significantly slower than from other tissues, resulting in prolonged siRNA accumulation and significant target knockdown.
Last year, Egen scientists presented data at the American Association for Cancer Research's annual meeting on the use of the Staramine vascular endothelial growth factor receptor 2 (VEGFR2)-targeting siRNAs to inhibit lung tumor progression in a mouse model.
According to that presentation, repeat administration of Staramine-formulated VEGFR2 siRNAs at doses of around 2 mg/kg led to reductions of VEGFR2 transcript levels in isolated lung tumors by as much as 40 percent. Meanwhile, immunohistopathology of the lungs of treated mice indicated a significant decrease in vascular density in lung tumors and was consistent with an overall reduction in tumor burden in the mouse lungs.
Also in 2013, Egen presented animal data at the American Thoracic Society's International Conference on the inhibition of miR-145 to reverse the vascular remodeling associated with pulmonary arterial hypertension and improve cardiovascular functioning. In these studies, miR-145 antagonists were delivered using Staramine nanoparticles.
In addition to the potential of TheraSilence for EGEN-002 and future in-house programs, Tardugno said that a number of potential partners have expressed interest in using the delivery technology. He did not elaborate.