According to a news release from MD Anderson they have recently completed a study that shows that combining two separate chemotherapy agents is more effective than sequencing them one after another.
The current standard of care for the cytotoxic chemotherapy agents used to treat prostate cancer is to treat men with advanced metastatic castration-resistant prostate cancer (mCRPC) by the sequential use of single agent taxanes such as docetaxel and cabazitaxel. Usually, docetaxel is used as the “first-line” therapy while cabazitaxel is used as the “second-line” therapy. The use of these therapies as a combination therapy at the same time has not been well studied.
The results of a clinical trial were presented in Chicago at the American Society of Clinical Oncology Annual Meeting by researchers From MD Anderson. According to commentary from MD Anderson this trial may change the perspective on a role for combination chemotherapy in advanced disease.
The study compared the effectiveness of cabazitaxel alone versus cabazitaxel combined with carboplatin, a type of platinum chemotherapy in men with metastatic castrate-resistant prostate cancer (mCRPC). As of the ASCO presentation 160 men have been randomized receiving either the single or dual chemotherapy drug regimen. Each man received up to 10 cycles of chemotherapy.
The end points of the trial were Progression Free Survival, as well as changes in blood levels of prostate-specific antigen (PSA) and bone-specific alkaline phosphatase (BAP, a marker of prostate cancer in bone cells). In addition, safety and toxicity were monitored for both groups.
Their analysis of the data showed that median progression free survival(PFS0 was significantly longer for the men receiving the combination of treatments versus those receiving the single agent chemotherapy (6.7 months vs 4.4 months, respectively, p = 0.01). They also found that the reductions in both PSA scores as well as BAP were greater for the combination therapy group.
The PSA reductions that were greater than 50 percent occurred 60 percent of the time with combined chemotherapy vs. 44 percent with the single drug. PSA reductions greater than 90 percent occurred 28 percent of the time with two chemotherapy drugs vs. 20 percent with one. In addition, BAP reductions greater than 50 percent for combination vs. single drug were 63 percent and 25 percent respectively.
Given the potential level of side effects from the individual drugs they were surprised to find that they were actually comparable for both the single-drug regimen and two-drug regimen. In addition, there were no significant toxicity events.
Dr. Paul Corn, M.D., Ph.D. said, “We believe cabazitaxel-carboplatin combination chemotherapy may become the clinical standard for advanced prostate cancer once additional safety, efficacy and overall survival data is generated.
Corn, Amado Zurita-Saavedra, M.D., Sumit Subudhi, M.D. Ph.D., John Araujo, M.D. Ph.D., Jeri Kim, M.D., Eric Jonasch, M.D., Lance Pagliaro, M.D., Arlene Siefker-Radtke, M.D., Xuemei Wang, Elisabeth Heath, M.D., Christopher Logothetis, M.D. and Ana Aparicio, M.D.
Joel T. Nowak, M.A., M.S.W.