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Cancer Immunol Immunother. 2013 Oct;62(10):1547-51. doi: 10.1007/s00262-013-1458-y. Epub 2013 Aug 24.

Late divergence of survival curves in cancer immunotherapy trials: interpretation and implications.

Author information

1
Sahlgrenska Cancer Center, University of Gothenburg, Box 425, 405 30, Göteborg, Sweden, fredrik.thoren@gu.se.

Abstract

Late divergence of survival curves of treated patients and controls is commonly seen in successful cancer immunotherapy trials. Although late survival curve divergence may be caused by a delayed action of therapy, it may also be related to early effects of the treatment. We suggest that late survival divergence most often reflects a specific benefit of therapy for patients who suffer from a comparatively slow progression of disease. The occurrence of delayed survival curve divergence has important implications for the statistical analysis of immunotherapy trials. Thus, it leads to non-proportional hazard ratios that make commonly used statistical tests, e.g., the logrank test, suboptimal. It is therefore suggested that the statistical analysis of immunotherapy trials primarily should be based on a test that compares the survival curves at or after a prespecified, fixed, late time point.

PMID:
23979447
DOI:
10.1007/s00262-013-1458-y
[Indexed for MEDLINE]

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