报告题目: Analysis of Stratified Mark-Specific Proportional Hazards Models under Two-Phase Sampling with Application to HIV Vaccine Efficacy Trials
报告人: Professor Yanqing Sun, Department of Mathematics and Statistics, University of North Carolina at Charlotte, USA
报告摘要: An objective of preventive HIV vaccine efficacy trials is to understand how immune responses to specific protein or sub-protein sequences of HIV associate with the level of vaccine efficacy to prevent infection with sequences of HIV targeted by the immune responses. The vaccine-induced immune response biomarkers are often measured via two-phase sampling for efficiency. Motivated by this objective, we investigate the stratified mark-specific proportional hazards model under two-phase sampling, where the mark is the genetic distance of an infecting HIV sequence to an HIV sequence represented inside the vaccine. The estimation and inference procedures based on inverse probability weighting of complete-cases and the augmented inverse probability weighted complete-case are developed. The asymptotic properties are derived, and their finite-sample performances are examined in a comprehensive simulation study. The methods are shown to have satisfactory performance, and are applied to the RV144 vaccine trial to assess whether immune response correlates of HIV infection are stronger for HIV infecting sequences similar to the vaccine than for sequences distant from the vaccine.