Scott T. Tagawa, MD, assistant professor of medicine, medical director, Genitourinary Oncology Research Program, Weill Cornell Medical College, discusses the results of a study that evaluated the safety of abiraterone acetate combined with docetaxel in patients with metastatic castration-resistant prostate cancer that were presented at the 2014 Genitourinary Cancer Symposium in San Francisco.
Tagawa says the data presented at the symposium is a preliminary presentation of the full data set for cohorts 1 and 2 with a mention of the first part of cohort 3. In cohort 1, patients received slightly lower doses of both abiraterone and docetaxel while in cohort 2, patients received full doses of docetaxel with a lower dose of abiraterone. Cohort 3 treated patients to full doses of both drugs, Tagawa says.
The results of the data from cohorts 1 and 2 showed that there were no unexpected dose-limiting toxicities. A full pharmacokinetic evaluation was done for each drug alone as well as in combination, Tagawa says. This showed that there were no significant differences from expectations in toxicity for the combination.
Tagawa says the combination is interesting because there is a theory that the mechanisms of actions for the two drugs are similar in their approach to targeting the AR pathway. It was recently discovered that early chemotherapy has a longer-term benefit in overall survival, which could bring docetaxel back into an early setting, Tagawa believes.
Preliminary efficacy data showed that each patient had at least a 50% decrease in PSA. Additionally, 80% of the patients had at least a 90% decrease in PSA at some point during treatment, Tagawa notes.
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