Comparative analysis of the effectiveness of abiraterone before and after docetaxel in patients with metastatic castration-resistant prostate cancer

AIM: To study the efficacy and safety of abiraterone in patients with and without prior chemotherapy.METHODS: The databases including Pub Med and abstracts presented at the American Society of Clinical Oncology meetings up to April 2014 were systematically searched. Eligible studies included randomized controlled trials(RCTs) in which abiraterone plus prednisone was compared to placebo plus prednisone in metastatic castration-resistant prostate cancer(CRPC) patients. The summary incidence, relative risk, hazard ratio and 95%CI were calculated using random or fixed-effects models. Heterogeneity test was performed to test between-study differences in efficacy and toxicity.RESULTS: A total of two phase III RCTs were included in our analysis, with metastatic CPRC patients before(n = 1088) and after chemotherapy(n = 1195). Prior chemotherapy did not significantly alter the effect of abiraterone on overall survival(P = 0.92) and prostatespecific antigen(PSA) progression-free survival(P = 0.13), but reduced its effect on radiographic-prog-ression-free survival(P = 0.04), objective response rate(P < 0.001), and PSA response rate(P < 0.001). Prior chemotherapy significantly increased the specific risk of fluid retention and edema(P < 0.001) and hypokalemia(P < 0.001), but decreased the risk of all-grade hypertension(P < 0.001) attributable to abiraterone. There was no significant difference of cardiac disorders associated with abiraterone between the two settings(P = 0.58). CONCLUSION: Prior chemotherapy may reduce the effectiveness of abiraterone in patients with metastatic CRPC.

Novel therapy for advanced gastric cancer

Gastric cancer(GC) is a common lethal malignancy.Gastroesophageal junction and gastric cardia tumors are the fastest rising malignancies due to increasing prevalence of obesity and acid reflex in the United States.Traditional chemotherapy remains the main treatment with trastuzumab targeting human epidermal growth factor receptor 2 positive disease.The median overall survival(OS) is less than one year for advanced GC patients; thus,there is an urgent unmet need to develop novel therapy for GC.Although multiple targeted agents were studied,only the vascular endothelial growth factor receptor inhibitor ramucirumab was approved recently by the United States Food and Drug Administration because of its 1.4 mo OS benefit(5.2 mo vs 3.8 mo,P = 0.047) as a single agent; 2.2 mo improvement of survival(9.6 mo vs 7.4 mo,P = 0.017) when combined with paclitaxel in previously treated advanced GC patients.It is the first single agent approved for previously treated GC and the second biologic agent after trastuzumab.Even with limited success,targeted therapy may be improved by developing new biomarkers.Immune therapy is changing the paradigm of cancer treatment and is presently under active investigation for GC in clinical trials.More evidence supports GC stem cells existence and early stage studies are looking for its potential therapeutic possibilities.