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Sanusi B, Cai J, Hudgens MG. Nonparametric estimation of marked survival data in the presence of dependent censoring. Stat Med 2023; 42:1995-2008. [PMID: 36945185 PMCID: PMC10192031 DOI: 10.1002/sim.9710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 02/24/2023] [Accepted: 03/07/2023] [Indexed: 03/23/2023]
Abstract
We consider nonparametrically estimating the joint distribution of a survival time and mark variable, where the survival time is subject to right censoring and the mark variable is only observed when the survival time is not censored. The possibility of dependent censoring is allowed for using inverse probability of censoring weights. The proposed estimator is shown to be consistent and asymptotically normal. Finite sample behavior of the proposed methods are investigated via simulation study. Finally, we illustrate the nonparametric estimator from a recent HIV vaccine efficacy trial.
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Affiliation(s)
- Busola Sanusi
- Janssen Research and Development, Spring House, Pennsylvania, USA
| | - Jianwen Cai
- Department of Biostatistics, University of North Carolina at Chapel Hill, North Carolina, USA
| | - Michael G. Hudgens
- Department of Biostatistics, University of North Carolina at Chapel Hill, North Carolina, USA
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Qi L, Sun Y, Juraska M, Moodie Z, Magaret CA, Heng F, Carpp LN, Gilbert PB. Neutralizing antibody correlates of sequence specific dengue disease in a tetravalent dengue vaccine efficacy trial in Asia. Vaccine 2022; 40:5912-5923. [PMID: 36068106 PMCID: PMC9881745 DOI: 10.1016/j.vaccine.2022.08.055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 07/13/2022] [Accepted: 08/23/2022] [Indexed: 01/31/2023]
Abstract
In the CYD14 trial of the CYD-TDV dengue vaccine in 2-14 year-olds, neutralizing antibody (nAb) titers to the vaccine-insert dengue strains correlated inversely with symptomatic, virologically-confirmed dengue (VCD). Also, vaccine efficacy against VCD was higher against dengue prM/E amino acid sequences closer to the vaccine inserts. We integrated the nAb and sequence data types by assessing nAb titers as a correlate of sequence-specific VCD separately in the vaccine arm and in the placebo arm. In both vaccine and placebo recipients the correlation of nAb titer with sequence-specific VCD was stronger for dengue nAb contact site sequences closer to the vaccine (p = 0.005 and p = 0.012, respectively). The risk of VCD in vaccine (placebo) recipients was 6.7- (1.80)-fold lower at the 90th vs 10th percentile of nAb for viruses perfectly matched to CYD-TDV, compared to 2.1- (0.78)-fold lower at the 90th vs 10th percentile for viruses with five amino acid mismatches. The evidence for a stronger sequence-distance dependent correlate of risk for the vaccine arm indicates departure from the Prentice criteria for a valid sequence-distance specific surrogate endpoint and suggests that the nAb marker may affect dengue risk differently depending on whether nAbs arise from infection or also by vaccination. However, when restricting to baseline-seropositive 9-14 year-olds, the correlation pattern became more similar between the vaccine and placebo arms, supporting nAb titers as an approximate surrogate endpoint in this population. No sequence-specific nAb titer correlates of VCD were seen in baseline-seronegative participants. Integrated immune response/pathogen sequence data correlates analyses could help increase knowledge of correlates of risk and surrogate endpoints for other vaccines against genetically diverse pathogens. Trial registration: EU Clinical Trials Register 2014-001708-24; registration date 2014-05-26.
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Affiliation(s)
- Li Qi
- Biostatistics and Programming, Sanofi, 55 Corporate Drive, Bridgewater, NJ 08807, United States.
| | - Yanqing Sun
- Department of Mathematics and Statistics, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, United States.
| | - Michal Juraska
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Avenue North, Seattle, WA 98109, United States.
| | - Zoe Moodie
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Avenue North, Seattle, WA 98109, United States.
| | - Craig A Magaret
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Avenue North, Seattle, WA 98109, United States.
| | - Fei Heng
- Department of Mathematics and Statistics, University of North Florida, 1 UNF Drive, Jacksonville, FL 32224, United States.
| | - Lindsay N Carpp
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Avenue North, Seattle, WA 98109, United States.
| | - Peter B Gilbert
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Center, 1100 Fairview Avenue North, Seattle, WA 98109, United States; Department of Biostatistics, University of Washington, 3980 15th Avenue NE, Seattle, WA 98109, United States.
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