In a recent study, the targeted agent cabozantinib did not demonstrate an improvement in outcomes compared to prednisone, among men with advanced prostate cancer. These results were recently published in the Journal of Clinical Oncology.

Prostate cancer is the second leading cause of cancer-related deaths among men in the United States.  Metastatic prostate cancer refers to cancer that has spread to several and/or distant sites in the body.

There are several treatment options for prostate cancer, depending upon several variables of the cancer and patient characteristics. However, since prostate cancer is stimulated to grow from exposure to the male hormone, testosterone, a common therapeutic approach is to reduce the formation of testosterone in the body. This can be done through surgery or medications.

Researchers continue to evaluate novel ways in which to improve survival while maintaining quality of life among men with metastatic prostate cancer, particularly among those whose cancer progresses despite prior therapy to reduce testosterone levels.

Cabozantinib is an agent referred to as a kinase inhibitor. It was developed to target certain cellular pathways that stimulate the growth and spread of cancer cells. Cabozantinib targets the MET and VEGF receptors to reduce cancer progression. Previous trials evaluating cabozantinib have demonstrated anti-cancer activity among men with metastatic prostate cancer that has progressed despite prior therapy to reduce testosterone levels.

Due to prior study results, researchers continued to evaluate cabozantinib among patients with advanced prostate cancer. The recent phase III clinical trial, referred to as the COMET-1 trial, included 1,028 men with metastatic prostate cancer that had progressed following prior therapies, including therapy to reduce testosterone levels. Patients in the trial were treated with either cabozantinib, or prednisone (a steroid).

  • Overall, men treated with cabozantinib did not experience a significant difference in survival outcomes (11 months), compared to those treated with prednisone (approximately 10 months).
  • Although some cancer markers were improved among men treated with cabozantinib, there were no differences in prostate-specific antigen (PSA) levels between the two treatment groups.

The researchers concluded that among men with metastatic prostate cancer that progressed despite prior therapy, treatment with cabozantinib did not improve survival compared with prednisone.

Reference: Smith M, De Bono J, Sternberg C, et al. Phase III Study of Cabozantinib in Previously Treated Metastatic Castration-Resistant Prostate Cancer: COMET-1. J Clin Oncol. Published online before print July 11, 2016, doi: 10.1200/JCO.2015.65.5597.

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