Pazopanib as Second Line Therapy in Patients With Metastatic Prostate Cancer Refractory to Total Androgen Blockade
A growing body of literature supports the role of angiogenesis in the development and spread of a variety of human cancers including prostate cancer.
- Vascular endothelial growth factor (VEGF) expression is low in normal prostate tissue, but markedly increased in tumor tissues, and has a positive association with tumor stage and grade
- Plasma VEGF levels are significantly elevated in patients with hormone refractory prostate cancer (HRPC) compared to those patients with localized disease and have been associated with disease progression in other cancer patient population.
- The Cancer and Leukemic Group-B demonstrated that VEGF levels correlate with survival.
Pazopanib is a potent multi-target receptor tyrosine kinase inhibitor of vascular endothelial growth factor receptors.
|Study Design:||Intervention Model: Single Group Assignment
Masking: Open Label
Primary Purpose: Treatment
|Official Title:||A Study of Pazopanib as Second Line Therapy in Patients With Metastatic Prostate Cancer Who Have Received Prior Therapy With an LHRH Agonist.|
- Response Rate at 12 Weeks [ Time Frame: 12 weeks ]Response rate defined as 50% decrease in the Prostate Specific Antigen (PSA) level at week 12 compared to baseline
- Number Adverse Events, Grades 1-5 Using NCI-CTCAE v 3.0 [ Time Frame: 0-12 weeks ]Safety was evaluated by documentation of Adverse Events (AEs), by assessment of clinical laboratory findings, and by physicial examination, including measurement of vital signs and weight in all eleven subjects.
|Study Start Date:||July 2009|
|Study Completion Date:||October 2012|
|Primary Completion Date:||October 2012 (Final data collection date for primary outcome measure)|
Experimental: Advanced prostate cancer, treatment, pazopanib
Drug: Pazopanib (GW786034)
Pazopanib 800 mg daily x 12 weeks
Other Name: Pazopanib monohydrochloride salt GW786034
VEGF expression is low in all normal prostate tissue, but markedly increased in tumor tissue, and has a positive association with MVD (micro vessel density) tumor stage, grade, and disease-specific survival in patients with prostate cancer. VEGF is known to be under the influence of HIF-1α, which is also up-regulated in the majority of prostate cancer tissue. It has been shown that complete androgen blockade down-regulates VEGF expression via the HIF-1α pathway with concomitant up-regulation of thrombospondin and induction of endothelial cell apoptosis. The VEGF pathway appears to be the dominant vascular formation pathway in prostate cancer with bFGF having a lesser role.
Pazopanib , a hydrochloride salt, is a small molecule inhibitor of several tyrosine kinases, ie: VEGF 1, 2, 3, c-KIT and platelet-derived growth factor receptors. The broad blockade of the VEGF receptors should interfere with the VEGF/VEGF-receptor pathway, and have an impact on cell growth.
According to the NCCN guidelines , first line therapy for metastatic prostate cancer is considered total androgen blockade, either utilizing orchiectomy and/or LH/RH agonists plus Casodex.
Second line therapy would depend on the patient's response to first line therapy, urgency of a response, and the location of metastatic disease.
Pazopanib has been explored in several settings. It has recently been looked at with Bicalutamide in hormone refractory prostate cancer. The second study was with earlier disease, i.e. D-0 relapse androgen-sensitive patients. The University of Chicago has a study looking at the sub-population of prostate cancer patients that have a "chemical relapse" in which patients are given one shot of Lupron, and if the PSA is adequately suppressed, the patients are randomized between pazopanib and placebo.
Please refer to this study by its ClinicalTrials.gov identifier: NCT00945477
|United States, Illinois|
|Bloomington, Illinois, United States, 61701|
|Ottawa, Illinois, United States, 61350|
|Pekin, Illinois, United States, 61554|
|Illinois Cancer Care|
|Peoria, Illinois, United States, 61615|