Dose-Escalation Study of RRx-001 in Combination With Whole Brain Radiation in Subjects With Brain Metastases

The purpose of this research study is to test the safety and activity of whole brain radiation therapy with RRx-001, an experimental radiation sensitizer, in participants with brain metastases. As a radiation sensitizer, RRx-001 may increase the effect of whole brain radiation, the standard of care for brain metastases, on cancer cells in a specific target area while reducing damage to normal healthy cells. The ability to sensitize the cancer cells to radiation sets off a 'domino effect' of free radical damage in the tumor from a given amount or dose of radiation. This study, which is called BRAINSTORM, since RRx-001 is associated with the development of a "free radical storm" in the brain tumors, is divided into two stages. In the first stage, approximately 3 participants at a time will be entered at a particular dose level of RRx-001 and then observed in order to see whether that dose results in side effects with radiation. If no bad side effects are observed, a second group of approximately 3 subjects will be given a slightly higher dose of RRx-001 and also monitored for side effects with radiation. This process will be repeated until a dose is reached, which has the most activity against the cancer cells without unacceptable side effects. At this point, more participants will be entered at this dose level until a maximum enrollment of approximately 30 participants has been reached. RRx-001 releases a gas called nitric oxide, which widens the diameter of blood vessels, and allows the delivery of more oxygen to tumors. The presence of oxygen in tumors is critical for the effectiveness of radiation therapy, since cancer cells are about two to three times more vulnerable to radiation when oxygen is present. The reason that cancer cells are so much more vulnerable to the effects of radiation when oxygen is present is that radiation relies on the formation of harmful molecules known as free radicals that damage proteins and genetic material (DNA); without oxygen lower levels of free radicals are produced. Changes in the diameter go blood vessels will be studied by magnetic resonance imaging. Unlike chemotherapies or other radiation sensitizers, RRx-001 does not have to enter the tumor to be effective because nitric oxide, as a gas, is able to spread or diffuse from the bloodstream into cancer cells.