Adventrx Pharmaceuticals Inc. has announced the initiation of a phase II clinical trial using CoFactor in the treatment of refractory metastatic breast cancer.

CoFactor (ANX-510) is a folate-based biomodulator drug designed to enhance the activity and reduce associated toxicity of the widely used cancer chemotherapeutic agent 5-fluorouracil (5-FU).

This study builds on the results of earlier studies and will more fully investigate the efficacy and safety of CoFactor for patients with previously treated, advanced breast cancer.

"The initiation of this phase II clinical trial for CoFactor represents an important milestone in the global registration strategy for our lead product development program," said Evan M Levine, chief executive officer of Adventrx. "We are enthusiastic about CoFactor's potential to enhance the efficacy and safety of 5-FU chemotherapy in the treatment of refractory breast cancer."

"We are pleased to have launched this study of CoFactor in combination with 5-FU in advanced breast cancer," added James A. Merritt, MD, president and chief medical officer of Adventrx. "The CoFactor and 5-FU regimen has demonstrated activity in multiple tumour types, including breast in a phase I clinical trial, and we have safety data from other CoFactor studies in metastatic colorectal cancer that suggest CoFactor is well-tolerated. We believe a CoFactor plus 5-FU regimen could offer a worthwhile alternative in the overall management of breast cancer."

This phase II clinical trial is a single arm, multi centre study to evaluate the safety and efficacy of treatment with CoFactor plus 5-FU in advanced breast cancer patients who have failed anthracycline and taxane chemotherapies.

Patients will be treated with CoFactor followed by 5-FU administered by IV bolus weekly for 6 weeks, with tumour and safety assessments every 8 weeks. The primary endpoint for the study is objective response rate (RECIST criteria), and secondary endpoints are duration of response, progression free survival, overall survival and incidence and severity of adverse events (AEs), as defined by the NCI Common Terminology Criteria. A total of 31 patients are expected to be enrolled at 6 clinical sites.

According to the American Cancer Society, breast cancer is the most frequently diagnosed cancer in American women and the second leading cause of cancer-related deaths in women after lung cancer. Over 214,000 new cases of breast cancer and over 41,000 deaths from breast cancer are expected in the US in 2006. Despite advances made in treatment options that have led to a significant increase in survival and quality of life, metastatic disease is still incurable. Five-year survival rates decrease with advancing disease stage: from 98 per cent in localized disease to 80 per cent with regional spreading to only 26 per cent with metastatic disease.

CoFactor is a folate-based biomodulator drug designed to replace leucovorin to enhance the activity and reduce associated toxicity of the widely used cancer chemotherapy 5-fluorouracil (5-FU).