Sentence: Because gemcitabine has been considered a standard treatment for advanced pancreatic cancer for the past decade , several randomized trials have tested the combination of gemcitabine plus a second agent , including platinum based agents , topoisomerase inhibitors , taxanes , bevacizumab and cetuximab , as biologically " targeted " agents .
Drug combination annotation:
[{'class': 'COMB', 'spans': ['gemcitabine', 'bevacizumab'], 'is_context_needed': True}, {'class': 'COMB', 'spans': [1, 3], 'is_context_needed': True}]