A group sequential test for treatment effect based on the Fine-Gray model

Biometrics. 2018 Sep;74(3):1006-1013. doi: 10.1111/biom.12871. Epub 2018 Mar 13.


Competing risks endpoints arise when patients can fail therapy from several causes. Analyzing these outcomes allows one to assess directly the benefit of treatment on a primary cause of failure in a clinical trial setting. Regression models can be used in clinical trials to adjust for residual imbalances in patient characteristics, improving the power to detect treatment differences. But, none of the competing risks methods currently available for use in group sequential trials adjust for covariates. We propose a group sequential test for treatment effect that, because it is based on the Fine-Gray model, permits adjustment for covariates. Our derivations show that its sequence of test statistics has an asymptotic distribution with an independent increments structure, which allows standard techniques such as O'Brien-Fleming designs and error spending functions to be employed to meet type I error rate and power specifications. We demonstrate the test in a reanalysis of BMT CTN 0402, a phase III clinical trial that evaluated an experimental treatment for the prevention of adverse outcomes following blood and marrow transplant. Moreover, using a simulation study of randomized group sequential trials, we demonstrate that the proposed method preserves the type I error rate and power at their nominal levels in the presence of influential covariates.

Keywords: Competing risks analysis; Covariate adjustment; Fine-gray regression model; Graft versus host disease; Group sequential design; Hematopoietic cell transplantation.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bone Marrow Transplantation / adverse effects
  • Clinical Trials as Topic
  • Computer Simulation
  • Endpoint Determination / statistics & numerical data*
  • Humans
  • Long Term Adverse Effects / prevention & control
  • Peripheral Blood Stem Cell Transplantation / adverse effects
  • Risk
  • Treatment Failure*
  • Treatment Outcome*