Group sequential designs for cancer immunotherapy trial with delayed treatment effect

Area of Science:

• Oncology
• Biostatistics
• Clinical Trial Design

Background:

• Cancer immunotherapy trials often show delayed treatment effects, violating proportional hazards assumptions and reducing the power of the log-rank test.
• Existing group sequential designs may not be suitable for futility interim monitoring due to a high false-negative rate caused by delayed treatment effects.

Purpose of the Study:

• To propose an improved group sequential design for cancer immunotherapy trials that accounts for delayed treatment effects.
• To enhance statistical power and reduce false-negative rates in interim monitoring.

Main Methods:

• A novel group sequential design utilizing a piecewise weighted log-rank test is proposed.
• This design employs an event-driven approach, conducting interim looks only after a planned number of events are observed post-delay.
• The method is compared with group sequential designs using Fleming-Harrington weighted log-rank tests.

Main Results:

• The proposed piecewise weighted log-rank test design effectively avoids false-negative rates associated with delayed treatment effects.
• The event-driven approach ensures robustness against various survival, accrual, and censoring distributions.
• The design enhances the efficacy of cancer immunotherapy trials.

Conclusions:

• The proposed piecewise weighted log-rank test offers a robust and effective group sequential design for cancer immunotherapy trials with delayed treatment effects.
• This approach optimizes interim monitoring, improving trial efficiency and reliability.