Group sequential tests for treatment effect on survival and cumulative incidence at a fixed time point

Lifetime Data Anal. 2020 Jul;26(3):603-623. doi: 10.1007/s10985-019-09491-z. Epub 2019 Nov 15.


Medical research frequently involves comparing an event time of interest between treatment groups. Rather than comparing the entire survival or cumulative incidence curves, it is sometimes preferable to evaluate these probabilities at a fixed point in time. Performing a covariate adjusted analysis can improve efficiency, even in randomized clinical trials, but no currently available group sequential test for fixed point analysis provides this adjustment. This paper introduces covariate adjusted group sequential pointwise comparisons of survival and cumulative incidence probabilities. Their test statistics have an asymptotic distribution with independent increments, permitting use of common stopping boundary specification methods. These tests are demonstrated through a redesign of BMT CTN 0402, a clinical trial that evaluated a prophylactic treatment for adverse outcomes following blood and marrow transplantation. A simulation study demonstrates that these tests maintain the type I error rate and power at nominal levels under a variety of settings involving influential covariates.

Keywords: Competing risks; Direct binomial regression; Graft versus host disease; Group sequential design; Hematopoietic cell transplantation; Survival analysis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Bias*
  • Clinical Trials as Topic
  • Computer Simulation
  • Humans
  • Incidence
  • Regression Analysis*
  • Survival Analysis*
  • Time
  • Treatment Outcome*