title: Patient accrual and interim statistical analysis in long-term randomized clinical trials: the French chronic lymphocytic leukemia CLL 80 protocol as a case study.
abstract: The CLL 80 clinical trial of treatment for chronic lymphocytic leukemia was designed using a three-stage prognostic classification. Within each stage patients received one of two treatments allocated by randomization, two adjacent stages having a common treatment. The fixed-sample design required 850 patients entered over a period of 8.5 years. Active patient recruitment led to 741 patients being randomized in four years. The first interim analysis, carried out at this point, showed a treatment difference in one stage which was statistically significant (p = 0.001) and justified an early termination of the protocol. This paper discusses practical aspects of patient accrual and interim analysis in this study.
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D002699:Chlorambucil / Q000008:administration & dosage; D002986:Clinical Trials as Topic; D003520:Cyclophosphamide / Q000008:administration & dosage; D004317:Doxorubicin / Q000008:administration & dosage; D004334:Drug Administration Schedule; D005602:France; D006801:Humans; D007945:Leukemia, Lymphoid / Q000188:drug therapy*; D011241:Prednisone / Q000008:administration & dosage; D011379:Prognosis; D011897:Random Allocation; D012107:Research Design; D013997:Time Factors; D014750:Vincristine / Q000008:administration & dosage
chemical_list: D002699:Chlorambucil; D014750:Vincristine; D004317:Doxorubicin; D003520:Cyclophosphamide; D011241:Prednisone