Patients with metastatic lesions of the lung, liver, or bone will be candidates for treatment. Within three weeks of the initial treatment planning, a 15 Gy dose (per lesion site) of SBRT will be administered. Prior to SBRT, patients will initiate Nelfinavir oral therapy twice daily for 7 days. Once SBRT is completed, the patient will repeat the same Nelfinavir therapy for an additional 7 days for a total of 14 days of treatment.

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.

Inclusion Criteria

• Patient's tumor(s) to be treated is(are) ≤ 5.0 cm or ≤250 cm3
• Patient must have metastasis at one or more of the following sites: bone, liver, lymph node and/or lung. No more than five lesions will be treated.
• Histological confirmation of malignancy (primary or metastatic tumor).
• Patient may have any prior therapy allowed aside from having had prior radiotherapy to the treatment site (see exclusion criteria 5.2.3).
• Patient must be ≥ 18 years of age.
• Patient must have a life expectancy ≥ 9 months.
• Patient must have an Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2.
• Patient must have normal organ and marrow function.
• Patient must have the ability to understand and the willingness to sign a written informed consent document.

Exclusion Criteria:

• Patients who have had chemotherapy or radiotherapy within 2 weeks prior to entering the study
• Patients receiving any other investigational agents
• Patient who has had any prior radiotherapy to the treatment site(s)
• Patients taking drugs that are contraindicated with nelfinavir, including any of the following:

Amiodarone, Quinidine, Rifampin, Dihydroergotamine, Ergonovine, Ergotamine, Methylergonovine, Hypericum perforatum (St. John's wort), Lovastatin, Simvastatin, Pimozide, Midazolam, Triazolam

• Women of child bearing potential who refuse to take a pregnancy test prior to treatment
• Participation in another concurrent treatment protocol while being treated on this protocol and through to 3 months after treatment on this protocol has ended
• Pregnant women
• Inability to understand the informed consent document
• Inability to sign the informed consent document
• Poor liver function suggestive of cirrhosis or steatohepatitis

38 patients were enrolled but one patient withdrew consent. The analysis included a total of 37 patients.

Up to 36 months.

All AEs were recorded throughout the study, however there were only 5 grade 3 adverse events in three patients as defined by CTCAE.