Accelerate vaccine development using seamless phase 2/3 trial designs.

Area of Science:

• Vaccinology
• Clinical Trial Design
• Biostatistics

Background:

• Traditional vaccine development is lengthy and expensive, involving three distinct phases.
• The rapid development of COVID-19 vaccines underscored the need for accelerated approval processes.
• This article focuses on a seamless phase 2/3 trial design to expedite vaccine development, particularly for multi-valent vaccines.

Purpose of the Study:

• To compare the performance of a seamless phase 2/3 design against conventional trial designs.
• To evaluate key performance metrics including power, error rates, sample size, and trial duration.
• To demonstrate the efficiency of the seamless design using a simulated 9-valent HPV vaccine trial.

Main Methods:

• Utilized simulation to model and compare trial designs.
• Evaluated performance across three distinct cases.
• Assessed metrics such as overall power, type I error rate, average sample size, trial duration, early stopping percentage, and dose selection accuracy.

Main Results:

• The seamless design, using interim efficacy analyses, reduced sample size by an average of 555.73 subjects and trial duration by 10.29 months, while increasing power by 3.70% when the vaccine was effective.
• When the experimental vaccine was less effective, the seamless design saved an average of 887.73 subjects.
• The type I error rate was consistently maintained below 0.025 across scenarios.

Conclusions:

• The seamless phase 2/3 design is a highly effective strategy for vaccine development.
• This design offers versatility through early stopping, sample size re-estimation, and shortened trial durations.
• The approach is particularly beneficial for expediting the development and approval of multi-valent vaccines.