Alnylam Pharmaceuticals this week announced the publication of data from its phase I trial of the siRNA-based liver cancer drug ALN-VSP.
The paper was published in the online edition of Cancer Discovery.
ALN-VSP comprises siRNAs against two targets: vascular endothelial growth factor, which is associated with angiogenesis; and kinesin spindle protein, which has been linked to cell proliferation in various cancers. It is formulated in lipid nanoparticles developed by Tekmira Pharmaceuticals, and is administered intravenously.
In mid-2011, Alnylam presented data from a phase I trial of the drug, showing that it was safe and well tolerated in 41 patients with advanced solid tumors with liver involvement who have either not responded to standard treatment or whose disease has progressed after treatment (GSN 6/9/2011).
Alnylam said at the time that some dose-limiting toxicities were observed, including a previously reported liver failure and death in one patient with “extensive hepatic metastases” at the 0.7 mg/kg dose level; transient thrombocytopenia in two patients at the 1.25 mg/kg dose level; and hypokalemia in one patient at the 1.5 mg/kg dose level.
Additionally, two patients with endometrial cancer experienced elevated white blood cell counts that were “possibly related” to ALN-VSP02 treatment, but these patients continued in the study.
There were also hints of efficacy, with one patient with endometrial cancer and multiple liver lesions experiencing a roughly 70 percent reduction in tumor burden at the 0.7 mg/kg dose.
Alnylam has licensed the drug to Ascletis in China, and has said it would only continue its development in the rest of the world with the help of a yet-to-be-found partner.