Researchers from the U.S. have reported that efaproxiral (Efaproxyn™) improves survival in the treatment of patients with brain metastases. These results were reported at the 29th European Society of Medical Oncology Congress held in Vienna, Austria, October 29 – November 2, 2004.
Brain metastases, or cancer that has spread to the brain from other locations in the body, have proven difficult to treat with available techniques. Chemotherapy has not yielded optimal anti-cancer responses because the drugs do not effectively pass through the blood-brain barrier. The effectiveness of radiation therapy has also been limited by low oxygen levels in cancer cells, a condition called hypoxia.
Efaproxiral is a radiosensitizer, which is a drug that increases the sensitivity of cells to radiotherapy. Radiation therapy tends to provide better anti-cancer responses in tissue that has sufficient amounts of oxygen. Efaproxiral appears to aid in the delivery of oxygen from the blood to hypoxic cells, making them more sensitive to radiation therapy. Efaproxiral has not yet been approved by the FDA and is still being evaluated in clinical trials.
The phase III, international study of efaproxiral presented at ESMO involved 515 patients with newly diagnosed brain metastases; 397 of these patients had non-small cell lung cancer (NSCLC) or breast cancer and the study design included a planned analysis of this subgroup. All patients were treated with oxygen and whole-brain radiation therapy (WBRT). Approximately half of the patients (271) also received efaproxiral prior to WBRT.
Results showed that the median survival time for all patients was not significantly different between those that received efaproxiral and those who received only WBRT and oxygen, but there was a significant difference in survival for the patients who had NSCLC or breast cancer. (see table)
The researchers calculated that these increases in median survival with efaproxiral translated into a reduction in the risk of death of 13% for all patients treated with efaproxiral and 18% for NSCLC and breast cancer patients treated with efaproxiral.
In an analysis of the outcomes of patients with breast cancer, the researchers reported that 17% of those that received efaproxiral lived 2 years or more, compared to none of the patients who underwent WBRT with oxygen. However, since the researchers had not planned to evaluate only breast cancer patients, these results are viewed as preliminary. A clinical trial, called the ENRICH study, is actively enrolling patients in North America to confirm these findings.
The researchers concluded that the addition of efaproxiral to WBRT led to a significant reduction in the risk of death for all eligible patients, as well as for eligible patients with either NSCLC or breast cancer.
Reference: Suh JH, Baldassarre S, Nabid A, et al. Standard whole brain radiation therapy (WBRT) plus supplemental oxygen (O2) with or without efaproxiral (EFAPROXYNTM) in patients with brain metastases: updated survival results of the randomized REACH (RT-009) study. Proceedings from the 29th ESMO Congress, Vienna, Austria, October 29 – November 2, 2004 (Abstract #785).
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