Sentence: It was concluded that cytosine arabinoside in combination with vincristine and prednisone is an effective but toxic antileukemic regimen which did not produce a major improvement in remission duration .
Drug combination annotation:
[{'class': 'NEG', 'spans': ['cytosine arabinoside', 'vincristine', 'prednisone'], 'is_context_needed': False}]