More from my explorations at the American Association of Cancer Researchers (AACR) conference in Washington, D.C.
Abstract 5386 described a study using a thalidomide analogue called lenalidomide (Revlimid), in combination with Taxotere, which currently is the only approved drug for chemotherapy for advanced, metastatic castrate resistant prostate cancer.
In the abstract, presented as a poster, Jake Y. Henry, of St. George’s University in London, said that in mouse models of prostate cancer and bench experiments with prostate cancer cell lines, a combination of the two drugs:
• Appeared to reduce the concentration of docetaxel needed to inhibit growth of half the cancer cells by 42%, thereby improving the ability of docetaxel to impact cells normally resistant to the drug.
• Appeared to show that lenalidomide by itself could inhibit cell invasion by prostate cancer cells driven by epidermal growth factor (EGF) in PC3 and DU145 cell lines in a dose-dependent fashion.
• Improved survival of laboratory animals by 59 days compared with 48 days for lenalidomide alone or 40 days for docetaxel alone with a corresponding reduction in tumor growth.
“These results support the use of lenalidomide in combination with docetaxel as an effective treatment for patients with castrate resistant prostate cancer,” Henry wrote in support of his poster presentation.
Niranjan Awasthi, PhD, a research scientist at the University of Texas Southwestern Medical School at Dallas, who was not involved in the experiments, said that “the effect we are seeing here is encouraging” However, the effects of treatment were not long-lasting. “After a while, the tumor cell growth catches up with the combination as well,” he noted. “There is an initial delay in growth, but it is not long lasting.”
Despite this, Henry, in his poster and abstract, noted that clinical trials using the combination are under way. He noted that the combination of docetaxel with agents not exhibiting overlapping toxicities is required in treatment of hormone-resistant prostate cancer. He concluded that docetaxel and thalidomide when combined are effective in treating patients with metastatic prostate cancer.
I want to point out that in this study all cell lines of prostate cancer were studied. As we are finding out and I have already written about, different cell lines will respond differently to specific drug treatments. Now that we know that docetaxel with Lenalidomide will exhibit positive results in some men, we need to separate out which cell lines will respond and in which genetic structures the treatment will respond in a positive way.
Henry J, et al “Lenalidomide enhances the anti-prostate cancer activity of docetaxel in vitro and in vivo” AACR 2010.
Joel T Nowak, MA, MSW