Lessons from the comparison of two randomized clinical trials using gemcitabine and cisplatin for advanced biliary tract cancer

There had been no standard chemotherapy established for advanced biliary tract cancer (BTC) until 2009, when the combination of cisplatin and gemcitabine (GC) was adopted as a first line standard chemotherapy option based on the results from two randomized studies: ABC-02, a UK investigator-initiated trial and the largest randomized phase III study in this tumor type with 410 patients; and BT22, a Japanese, industry-sponsored, randomized phase II study with 83 patients. In this review, investigators from both studies collaborated to compare protocols, patient characteristics, and outcomes of both studies including sub-analyses of study results. Although both studies showed GC combination therapy to be more effective than monotherapy, a detailed comparison revealed disparities between efficacy and safety end-points between the studies, which did not necessarily arise from different populations but from differences in protocol design. This review provides clinicians with insights for advanced BTC clinical study design and interpretation of historical studies.