Sunesis Pharmaceuticals Presents Updated Clinical Data From Ongoing Phase 2 Trial of Voreloxin (Formerly SNS-595) in Ovarian Can

Positive Interim Safety and Efficacy Data Reported



SOUTH SAN FRANCISCO, Calif., May 31  /PRNewswire-FirstCall/ -- Sunesis Pharmaceuticals, Inc. (NASDAQ:SNSS) today presented an update of interim data from the company's ongoing Phase 2 clinical trial of its lead product candidate, voreloxin (formerly SNS-595), in platinum-resistant ovarian cancer patients at the 44th American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.

"Voreloxin is a promising anti-cancer agent demonstrating encouraging signs of single-agent clinical activity in ovarian cancer patients who have failed prior rounds of treatment," said William McGuire, M.D., Medical Director of the Harry and Jeanette Weinberg Cancer Institute at Franklin Square and principal investigator for the Phase 2 clinical trial. "Importantly, treatment with voreloxin has resulted in disease control among approximately half of patients treated and the drug has been very well tolerated.  Taken together, these data support a potentially broad therapeutic window for this product candidate and I look forward to seeing the outcomes of treatment with voreloxin at the higher dose levels for patients now enrolling in this study."

To date, voreloxin administered as a single agent at a dose of 48 mg/m(2) once every 21 days has demonstrated clinical activity in platinum-resistant ovarian cancer patients.  Thus far, of 62 women evaluable for best response at that dose, one patient had a complete response, five patients had partial responses (one unconfirmed) and forty-five patients achieved stable disease. Forty-eight percent of these 62 patients achieved disease control, defined as stable disease for 90 days or more or a complete or partial response.  The preliminary median Progression Free Survival was 91 days, or 13 weeks, at the 48 mg/m(2) dose; twenty-three patients treated at this dose remained on study as of May 12, 2008.

All patients enrolled in the trial have previously failed treatment with platinum-containing regimens, and 26 patients have also failed prior treatment with doxorubicin HCl liposome injection (Doxil(R)).  Both platinum-resistant and Doxil-resistant patients in the Phase 2 clinical trial have responded to voreloxin therapy.

In March, based on the indications of clinical activity and the acceptable tolerability profile demonstrated in this Phase 2 clinical trial, Sunesis increased the dose of voreloxin in this trial to 60 mg/m(2) once every 28 days.  Thirty-four patients have been enrolled at the 60 mg/m(2) dose level. To date, with an initial eight patients evaluable for efficacy response, one patient has achieved a partial response.

Voreloxin has been well-tolerated in the platinum-resistant ovarian cancer population.  With 65 patients evaluable for safety at the 48 mg/m(2) dose and 20 patients evaluable for safety at the 60 mg/m(2) dose, low rates of febrile neutropenia (