The recently conducted observational Embryotox cohort study on mRNA COVID-19 vaccination aimed to assess the safety of mRNA COVID-19 vaccines in pregnancy. Here, we focus on the methodological approach used to assess the effect of the vaccination on adverse pregnancy outcomes such as spontaneous abortion and stillbirth. The data featured delayed study entry and cohort crossover as well as...
We consider a two-arm randomized clinical trial in precision oncology with time-to-event endpoint. Patients in the control arm receive standard of care (SOC) treatment whereas patients in the experimental arm are offered personalized treatment, e.g. on the basis of molecular characterization of the disease. However, some patients in the experimental arm will not receive personalized treatment...
The assessment of allogeneic stem cell transplantation (SCT) over standard continued chemotherapy in a clinical trial of childhood leukaemia is not straightforward. Standard chemotherapy will be stopped and SCT performed if a donor search identifies a suitable stem cell donor in registries of potential donors. Randomization to SCT or continued chemotherapy is usually not feasible due to...
Clinical trials often show treatment curves that diverge early and converge later, or vice versa—patterns that are poorly captured by the proportional-hazards assumption. We develop a joint inferential framework for two nonparametric functionals of censored survival data: the Kaplan–Meier–based Mann–Whitney effect and a novel temporal contrast separating early and late differences. The...
Time-to-event variables are among the most relevant primary efficacy endpoints in clinical trials, particularly in later phase oncology trials. When the proportional hazards assumption is expected to be severely violated, an alternative to the log-rank test is needed. Testing for differences in survival probabilities at a pre-defined time point offers one such option and has already been...
