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Activity Number:
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171
- SPAAC Poster Competition
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Type:
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Topic Contributed
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Date/Time:
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Tuesday, August 4, 2020 : 10:00 AM to 2:00 PM
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Sponsor:
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Biopharmaceutical Section
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Abstract #312652
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Title:
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Nonparametric Analysis of Delayed Treatment Effects Using Single-Crossing Constraints
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Author(s):
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Kijoeng Nam* and Nicholas C. Henderson and Dai Feng
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Companies:
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Merck and University of Michigan-Ann Arbor and AbbVie
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Keywords:
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censored data;
constrained estimation;
empirical likelihood;
immuno-oncology;
nonproportional hazards
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Abstract:
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Clinical trials involving novel immuno-oncology therapies frequently exhibit survival profiles which violate the proportional hazards assumption due to a delay in the treatment effect. In such settings, the survival curves in the two treatment arms may have a clear crossing before the two curves eventually separate. To flexibly model such scenarios, we describe a constrained empirical likelihood approach which constrains the survival functions to cross at most once without making any additional assumptions about when or how the survival curves in the two treatment arms are related. Our approach provides an estimate of a crossing time if such a crossing exists. In addition, our method generates interpretable measures of treatment benefit including crossing-conditional survival probabilities and crossing-conditional estimates of restricted residual mean life. We demonstrate the use and effectiveness of our approach with a large simulation study and an analysis of a recent combination therapy trial.
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Authors who are presenting talks have a * after their name.
