Threshold Pharmaceuticals, Inc., announced that under the US Orphan Drug Act, the US Food and Drug Administration (FDA) has granted orphan drug designation to Threshold's product candidate, glufosfamide, for the treatment of pancreatic cancer.

Orphan Drug designation is intended to encourage research and development of new therapies for diseases that affect fewer than 200,000 patients in the United States. Orphan Drug designation also provides eligibility for a special seven-year period of market exclusivity upon approval, potential tax credits for research, grant funding for research and development, reduced filing fees for marketing applications, and assistance with the review of clinical trial protocols.

"We are pleased to have received this orphan drug designation for glufosfamide," said Barry Selick, chief executive officer at Threshold. "This designation underscores the need for additional treatment options for this devastating disease."

Last month the company announced that it had completed enrolment in a pivotal phase 3 clinical trial evaluating glufosfamide for the potential second-line treatment of pancreatic cancer and a phase 2 clinical trial evaluating glufosfamide in combination with gemcitabine for the potential first-line treatment of pancreatic cancer. The company expects to have top-line results from both of these clinical trials by the end of 2006.

The phase 3 trial will evaluate approximately 300 previously-treated patients with locally advanced and/or metastatic pancreatic cancer who receive best supportive care (BSC) or glufosfamide (4500mg/m2) once every 3 weeks plus BSC. Best supportive care includes all medical or surgical interventions that a pancreatic cancer patient should receive to palliate the cancer but excludes treatment with systemic therapies intended to kill the cancer cells. The primary endpoint of this trial is overall survival as measured by time from randomization to death. The timing of the final analysis is therefore event- driven and will be conducted after the 258th death has occurred. In addition, the trial will investigate the potential efficacy of glufosfamide as determined by response rate, duration of response and progression-free survival, as well as safety.

The phase 2 trial will evaluate up to 28 previously-untreated patients with locally advanced and/or metastatic pancreatic cancer who receive the standard dose of gemcitabine (1000mg/m2) weekly for 3 of every 4 weeks plus glufosfamide (4500mg/m2) administered once every 4 weeks. In addition to safety, the trial will investigate the efficacy of glufosfamide in combination with gemcitabine as determined by response rate, duration of response, progression-free survival, overall survival, six- and twelve-month survival and change in serum tumour marker levels.