Cytotoxic chemotherapy with single agent taxanes such as docetaxel and cabazitaxel has been used for more than a decade as treatment for patients with advanced metastatic castration-resistant prostate cancer (mCRPC). Docetaxel is traditionally used as the “first-line” treatment and cabazitaxel as “second-line” treatment.
During the meeting of the American Society of Clinical Oncology researchers from the The University of Texas MD Anderson Cancer Center presented results of a clinical trial that might alter the current perspective on the role of combination chemotherapy for patients with advanced cancer.
In the trial, researchers assessed the efficacy of using only cabazitaxel or cabazitaxel in combination with carboplatin in a population of patients with mCRPC. 160 patients were subject to randomization with the single or dual chemotherapy drug regimen, for up to 10 chemotherapy cycles.
The researchers assessed Progression Free Survival (PFS), changes in prostate-specific antigen (PSA) and bone-specific alkaline phosphatase (BAP). For both patient groups the researchers also evaluated toxicity and safety.
Results showed that the median PFS was longer for patients who received the combination treatment in comparison with single agent chemotherapy (6.7 months versus 4.4 months).The results also showed that reduction in PSA and BAP levels was superior in the group of patients who received the combination treatment.
PSA reductions greater than 50% occurred 60% of the time upon combined chemotherapy treatment, in contrast to 44% with the single drug. PSA reductions greater than 90% happened 28% of the time with two chemotherapy drugs, compared to only 20% with one. Moreover, BAP reductions greater than 50% for combination or single drug were 63% and 25%, respectively.
Adverse events including anemia, neutropenia and fatigue were similar between both drug regimen groups. There were no observable toxicity events.
“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,” explained in a recent news release Paul Corn, M.D., Ph.D., an associate professor of genitourinary medical oncology at MD Anderson. “Dr. Ana Aparicio’s lab is currently developing tumor-specific biomarkers to identity patients with an aggressive variant of prostate cancer most likely to benefit from this approach.”