Threshold Pharmaceuticals, Inc. has initiated patient enrolment for a phase 2 clinical trial evaluating the efficacy and safety of glufosfamide in patients with recurrent, sensitive small cell lung cancer.

"The fatality rate among patients with recurrent small cell lung cancer is unfortunately high," said John C Ruckdeschel, M.D., Karmanos Cancer Institute, and a clinical investigator for the trial. "Currently available second-line chemotherapy has very limited expectations of benefit. This clinical trial explores another treatment option for these patients."

The current standards of care in treating recurrent, sensitive small cell lung cancer are a variety of single agent and combination regimens including topotecan, cyclophosphamide, doxorubicin, vincristine, irinotecan, ifosfamide and cisplatin.

Approximately 50 patients with extensive recurrent sensitive small cell lung cancer, who have progressed at least 60 days after completing chemotherapy, are planned to enrol in the phase 2, open-label, clinical trial at various sites in the United States, Ukraine and Russia. All patients are to receive 5000 mg/m2 of glufosfamide every three weeks for up to six cycles.

The primary efficacy endpoint of the trial is objective response rate. The secondary endpoints of the trial will evaluate duration of response, progression-free survival, overall survival, time to response and various safety and pharmacokinetic parameters. The study will also evaluate the effects of glufosfamide on lung cancer symptoms utilizing the Lung Cancer Symptom Scale (LCSS).

The clinical trial will utilize a two stage design to ensure there is an adequate response rate to justify complete enrolment. The first stage will enrol 21 patients and, at the end of this stage, the trial will be stopped if fewer than three patients have a response. If three or more responses are observed, an additional 29 patients will be enrolled. Tumour response will be evaluated at baseline and every six weeks using the Response Evaluation Criteria In Solid Tumours (RECIST).

Threshold is a biotechnology company focused on the discovery and development of small molecule therapeutics for the potential treatment of cancer.