Randomized RT +/- Lapatinib for Prostate Cancer Patients Receiving Radiation Therapy for Bone Metastases

Inclusion Criteria:

• History of adenocarcinoma of the prostate
• Evidence of metastatic disease
• Recommendation by patient's radiation oncologist to receive palliative external beam radiation for bone metastases secondary to metastatic prostate cancer
• Age 18 years or older
• Patients may be undergoing concurrent therapy with GNRH agonists or combined androgen blockade, as this is standard care for all advanced prostate cancers
• Ability to understand and the willingness to sign a written informed consent document

Exclusion Criteria:

• Any contraindication to lapatinib treatment.
• Prior radiation therapy within 30 days of the start of the planned course of treatment.
• Prior cytotoxic chemotherapy within 4 weeks of planned first dose of radiation.
• Prior administration of an ERBB1 or ERK1/2 inhibitor within 30 days of the start of the planned course of treatment.
• Patients with a medical necessity to continue active therapy with CYP3A4 strong inhibitors or inducers. The concomitant use of strong CYP3A4 inhibitors should be avoided (e.g., ketoconazole, itraconazole, clarithromycin, atazanavir, indinavir, nefazodone, nelfinavir, ritonavir, saquinavir, telithromycin, voriconazole, aprepitant). Grapefruit may also increase plasma concentrations of lapatinib and should be avoided. Once the strong inhibitor or inducer is discontinued, a washout period of approximately 1 week should be allowed before the lapatinib administration. If a patient is unable to discontinue these medications, they are not eligible for enrollment.
• Concurrent administration of any other investigational agents.
• Uncontrolled concurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, active hepatic or biliary disease with a Child-Pugh class of B or C, or psychiatric illness/social situations that would limit compliance with study requirements or that would interfere with accomplishing the study objectives.