SOME PRACTICAL ASPECTS OF THE INTERIM MONITORING OF CLINICAL-TRIALS

The decision to stop accrual early to a clinical trial is often diffic ult and multifaceted. Interim monitoring boundaries have been found us eful in U.S. oncology trials for such decisions for reasons described here. This paper also discusses rationale that lead to more conservati ve approaches to early stopping decisions than are currently employed. A recent initiative of the National Cancer Institute to achieve the o bjectives of independent data monitoring committees in the phase III c linical trials which it sponsors is also described.