Any progress in marketing in UK?, page-8

For HDE:

"The application, however, must contain sufficient information for FDA to determine that the device does not pose an unreasonable or significant risk of illness or injury, and that the probable benefit to health outweighs the risk of injury or illness from its use, taking into account the probable risks and benefits of currently available devices or alternative forms of treatment. Additionally, the applicant must demonstrate that no comparable devices are available to treat or diagnose the disease or condition, and that they could not otherwise bring the device to market."

In other words they don't have to produce proof of efficacy, but they do have to show it's safe and demonstrate how the benefits and risks compare to alternative current treatments. That means they would likely need to show how it compares to current chemotherapy treatments.

Don't get me wrong, I think it has great potential for downsizing tumors to enable curative resection in selected patients. But they need sufficient data to persuade the regulators and it's by no means certain that they have it.