Interim safety and pharmacodynamic results for ALN-VSP02, a novel RNAi therapeutic for solid tumors with liver involvement.

Abstract

3042 Background: Malignancies involving the liver represent a significant unmet medical need. ALN-VSP02 is a novel RNA interference (RNAi) therapeutic comprised of lipid nanoparticle-formulated small interfering RNAs (siRNAs) targeting the expression of vascular endothelial growth factor (VEGF)-A and kinesin spindle protein (KSP). Methods: A multicenter, open label, phase 1 dose escalation trial of ALN-VSP02 administered as a 15-minute iv infusion every two weeks was initiated in March 2009. Patients with advanced solid tumors are eligible if they have at least one measurable liver lesion and adequate liver function. The study uses a 3+3 design with 8 potential dose levels: 0.1, 0.2, 0.4, 0.7, 1.0, 1.25, 1.5, and 1.7 mg/kg. The primary objective is evaluation of safety and tolerability. Secondary objectives include assessment of PK and pharmacodynamic (PD) activity through DCE-MRI, biomarkers of angiogenesis, tumor biopsies, and response rate. Results: As of December 2009, 12 patients (most with colorectal cancer) have been treated on the first 4 dose levels. Forty-one doses have been administered; 0.1-0.4 mg/kg ALN-VSP02 was well- tolerated, with no hepatotoxicity. The only significant adverse event (AE) was a grade 2 infusion reaction in one patient at 0.4 mg/kg that responded to slowing of the infusion. At 0.7 mg/kg, a patient with pancreatic neuroendocrine tumor extensively involving both lobes of the liver died of hepatic failure following the second dose; this was deemed possibly related to study drug. Two additional patients treated at 0.7 mg/kg did not exhibit hepatotoxicity or any other significant AEs. PK showed Cmax and AUC that were dose proportional with no accumulation. Serial DCE-MRI scans performed 2-9 days after the first dose on 8 of the 12 patients showed a ≥40% decline in Ktrans in 12 of 15 liver tumors (80%) evaluated. This decline in blood flow was associated with extensive tumor necrosis in the patient with the neuroendocrine tumor. Conclusions: ALN-VSP02 was well-tolerated by the majority of patients across the first 4 dose levels. DCE-MRI results show preliminary evidence of an anti-VEGF effect. Accrual is continuing, and additional safety and PD data will be forthcoming. Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Alnylam Pharmaceuticals Alnylam Pharmaceuticals Alnylam Pharmaceuticals Alnylam Pharmaceuticals