Goodrich admits that when his group first proposed the strategy, “everyone said we were crazy.” Researchers have been trying to develop vaccines that contain whole cancer cells for more than 50 years, and although some formulations made it to clinical trials, they produced a poor immune response. None of the vaccines has been approved for humans, although one is available for pets.

The harsh methods previously used to stop cancer cells from reproducing, such as radiation, also caused them to shed their neoantigens, Goodrich says. He argues that the UV-based approach should work better because it preserves these potential immune stimulants.

The new clinical trial, launching this month at City of Hope in California and sponsored by PhotonPharma, aims to recruit eight patients with relapsed ovarian cancer. They will first undergo surgery to remove their tumors. Researchers will then expose the tumor cells to riboflavin and UV light and combine them with an immune-boosting additive known as an adjuvant to produce a custom vaccine. Participants will receive three doses of the vaccine, and researchers will check for side effects and measure immune responses.