Stereotactic Body Radiation With Nelfinavir for Oligometastases

The use of radiation therapy to treat metastatic tumors is well established and promising data are emerging with the use of SBRT for metastatic disease. However, the use of a single large fraction concurrent with a radiosensitizer as is being proposed is not of proven benefit. This investigation aims to confirm the safety and efficacy for SBRT used concurrently with a radiosensitizer in the setting of oligometastatic disease. The dose selected has been chosen with the belief that it is safe and effective based on prior experience with SBRT of lung cancer, pancreatic cancer and brain radiosurgery. All patients will be treated with a single fraction (per lesion site), targeted to the lesion concurrently with the radiosensitizer Nelfinavir. On the basis of this preclinical evidence, we propose a phase II study of Nelfinavir combined with SBRT in patients with oligometastatic disease. Because the standard dose of Nelfinavir for HIV patients is known to be safe and does inhibit the phosphorylation of Akt and decrease tumor hypoxia, we propose to study this in conjunction with a 15 Gy dose of SBRT. Experience with single-fraction pulmonary and pancreas SBRT provides a useful dose for this trial. With published data establishing the relative safety of large single-fraction SBRT to the lungs and pancreas, we have decided to proceed to determine the safety of 15 Gy SBRT concurrently with the radiosensitizer Nelfinavir. Once this is established, we propose to continue to enroll more patients to the study at this dose to determine the efficacy of this type of therapy. The proposed study represents an informed estimate based on current knowledge of SBRT doses and those administered in currently approved image-guided protocols (brain, base of skull, cervico-thoracic spine, pancreas and liver). This study will refine the current understanding of single fraction radiation tolerance for normal tissues, thereby making it possible to treat future patients more safely and aggressively.