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Activity Number:
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64
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Type:
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Topic Contributed
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Date/Time:
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Monday, August 12, 2002 : 8:30 AM to 10:20 AM
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Sponsor:
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Biopharmaceutical Section*
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| Abstract - #300510 |
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Title:
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Sample Size Re-estimation for Clinical Trials with Censored Survival Data
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Author(s):
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Yu Shen*+
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Affiliation(s):
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U. T. M. D. Anderson Cancer Center
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Address:
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1515 Holcomb Blvd, Box 447, Houston, Texas, 77030, USA
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Keywords:
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Clinical Trials ; Self-designing ; Weighted linear rank statistic ; Group-sequential procedure ; Staggered entry
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Abstract:
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A flexible design, with updating of sample size in clinical trials, is proposed for censored survival data. Patients enter trials serially and are subject to random loss to follow-up. The statistical inference is based on a weighted average of the linear rank statistics, where the weight function at each look depends on prior observed data. Such a weight function maintains the integrity of the variance of the final test statistic so that the type I error rate is preserved. The null hypothesis that two survival distributions are equal is tested only at the last step when the weight function is used up or when the efficacy result is sufficiently negative. Independent increments for the sequential linear rank statistic are key to deriving asymptotic properties of the test statistic. Some extensive simulations have been carried out to compare the operating characteristics of the method under different scenarios and for a comparison with the usual log rank test with fixed sample design.
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