March 20, 2006

Sunesis Pharmaceuticals has announced that patient treatment has commenced in a Phase II clinical trial of SNS-595, the company's lead anticancer therapeutic, in patients with small-cell lung cancer. The trial is an open-label, multicenter study designed to examine the safety and efficacy of SNS-595 as a second-line agent in patients with small-cell lung cancer who have failed first-line therapy. SNS-595 is a first-in-class cell-cycle modulator that (in vitro) kills proliferating cancer cells by inducing apoptosis, or programmed cell death, as cells progress through the S phase of the cell cycle.

Patients with small cell lung cancer who have failed first-line treatment will be enrolled at multiple centers in the U.S. and Canada. Eligible patients will receive SNS-595 every three weeks at a dose and schedule identified in Sunesis' Phase I study of SNS-595 in patients with advanced solid malignancies. The trial design anticipates enrolling 80 patients -- 40 that are refractory and 40 that are sensitive.