VANCOUVER, British Columbia, Dec. 22, 2010 (GLOBE NEWSWIRE) -- Tekmira Pharmaceuticals Corporation (Nasdaq:TKMR) (TSX:TKM), a leading developer of RNA interference (RNAi) therapeutics, announced today it has initiated patient dosing in a Phase 1 human clinical trial for its lead oncology product, TKM-PLK1. TKM-PLK1 targets polo-like kinase 1, or PLK1, a cell cycle protein involved in tumor cell proliferation and a validated oncology target. Inhibition of PLK1 prevents the tumor cell from completing cell division, resulting in cell cycle arrest and cancer cell death. Dr. Mark J. Murray, Tekmira's President and CEO, said, "We are pleased to have progressed to the point of initiating this Phase 1 human clinical trial for our lead oncology product. TKM-PLK1 has demonstrated anti-tumor efficacy in preclinical models of liver cancer as well as tumors outside the liver, supporting our strong belief that PLK1 represents an excellent target for RNAi. The commencement of this trial is a significant milestone for Tekmira. We are excited to move forward and expect to be in a position to report interim data from the Phase 1 trial in the second half of 2011." The Phase 1 clinical trial, conducted at three medical centers in the United States, will be an open label, multi-dose, dose-escalation study designed to evaluate the safety, tolerability and pharmacokinetics of TKM-PLK1 as well as the determination of the maximum tolerated dose. The trial will enroll up to 52 patients with advanced solid tumors. Secondary objectives of the trial will be to measure tumor response as well as the pharmacodynamic effects of TKM-PLK1 in patients providing biopsies. In addition to the Phase 1 human clinical trial, Tekmira is continuing discussions with the United States National Cancer Institute to design a second clinical trial to directly measure PLK1 knockdown and RNAi activity. TKM-PLK1 consists of a Tekmira proprietary lipid nanoparticle (LNP) formulation that encapsulates small interfering RNA (siRNA) designed to silence PLK1. TKM-PLK1 has been shown in preclinical animal studies to selectively kill cancer cells, while sparing normal cells in healthy tissue. PLK1 plays a key role in a number of significant cancer indications including colorectal, breast, non-small cell lung, and ovarian cancers. These diseases collectively affect more than 500,000 new patients each year in the United States.