In which scenario would the FDA likely require a human factors validation study?

The FDA would likely require a human factors validation study primarily to support the marketing authorization of combination products. Combination products, which integrate drug, device, and/or biological components, must demonstrate that users can safely and effectively operate them. Human factors validation studies assess how real users interact with these products to identify any potential use-related risks that could compromise safety or efficacy.

In this context, the study evaluates user interface design, instructions, and the overall user experience, ensuring that the intended users can utilize the device and medication as intended without confusion or error. Adequate validation is especially important in combination products due to the complexity of interactions between different components. As such, the requirement for these studies helps ensure patient safety and product effectiveness in real-world usage.

The other scenarios either do not specifically necessitate a human factors study or are not directly related to the safety and efficacy of user interactions with the product.