Sentence: Safety and efficacy of sorafenib followed by regorafenib or lenvatinib in patients with hepatocellular carcinoma .
Drug combination annotation:
[{'class': 'COMB', 'spans': ['sorafenib', 'regorafenib'], 'is_context_needed': True}, {'class': 'COMB', 'spans': [0, 2], 'is_context_needed': True}]