Sentence: Of the patients , 26 were treated with a chemotherapy regimen known to cause prolonged and sometimes permanent azoospermia ( BEACOPP -- bleomycin , etoposide , doxorubicin , cyclophosphamide , vincristine , procarbazine , and prednisolone ) and 26 with a regimen known to have a much milder effect on gonadal function ( ABVD -- doxorubicin , bleomycin , vincristine , and dacarbazine ) .
Drug combination annotation:
[{'class': 'POS', 'spans': ['bleomycin', 'vincristine', 'dacarbazine', 'doxorubicin'], 'is_context_needed': False}, {'class': 'NEG', 'spans': [0, 1, 2, 3, 4, 5, 6], 'is_context_needed': False}]