Sentence: This was a multicenter phase II pilot study of rituximab and modified hyper-fractionated cyclophosphamide , vincristine doxorubicin , dexamethasone ( modified R-hyperCVAD ) administered every 28 days for four to six cycles followed by rituximab maintenance therapy consisting of four weekly doses every 6 months for 2 years .
Drug combination annotation:
[{'class': 'POS', 'spans': ['rituximab', 'cyclophosphamide', 'vincristine', 'doxorubicin', 'dexamethasone'], 'is_context_needed': True}]