Sentence: From 1987 to 1991 , 194 previously untreated patients received vincristine and ifosfamide plus dactinomycin or etoposide for 1 - 2 years .
Drug combination annotation:
[{'class': 'NEG', 'spans': ['vincristine', 'ifosfamide', 'dactinomycin'], 'is_context_needed': True}, {'class': 'NEG', 'spans': [0, 1, 3], 'is_context_needed': True}]