Cancer Treated With Light: Japan's Photoimmunotherapy Is Years Ahead

Imagine a cancer treatment that targets tumor cells directly, then switches on with a beam of near-infrared light — leaving the healthy tissue around it largely untouched. In Japan, this is not a concept in a research paper. It has been an approved, insurance-covered treatment for several years. In the United States, it is still working its way through late-stage clinical trials.

The treatment is called photoimmunotherapy, and it is one of the clearest examples of a gap that runs quietly through modern medicine: therapies that are routine in Japan but not yet available to patients in America.

How it works

Photoimmunotherapy pairs a familiar cancer drug with a light-sensitive molecule. The therapy in question — cetuximab sarotalocan (brand name Akalux) — attaches a light-activated compound to cetuximab, an antibody that seeks out a protein found in high amounts on many head and neck cancer cells.

After the drug is infused and binds to the tumor, physicians apply red light at 690 nanometers directly to the site using a specialized laser system. The light activates the compound, which ruptures the targeted cancer cells. Because the drug concentrates in the tumor and the light is applied locally, the surrounding healthy tissue is largely spared. There is a second benefit: the way the cancer cells die appears to trigger the body’s own immune response against the tumor.

Where each country stands

Japan’s Ministry of Health, Labour and Welfare approved Akalux in September 2020 for unresectable, locally advanced or recurrent head and neck cancer, and national health insurance began covering it on January 1, 2021. Adoption has been real and steady: by late 2024, roughly 700 treatments had been performed by around 400 physicians at about 170 locations across Japan. In late 2024, an upgraded laser illumination system was rolled out to widen the range of tumors that can be treated.

In the United States, the same therapy has not been approved for commercial use. It holds an FDA Fast Track designation and is the subject of an ongoing global Phase 3 trial — combining the treatment with the immunotherapy drug pembrolizumab as a first-line option for recurrent head and neck cancer. That trial is still enrolling patients. In other words, an American patient generally cannot receive this treatment today outside of a clinical trial, while a patient in Japan can.

Why this gap exists

None of this means American medicine is behind in general — the United States leads the world in many areas of cancer care. But the two countries approve and adopt certain therapies on very different timelines. Japan’s regulatory system has, in several cases, moved innovative, locally developed treatments to patients faster, and its insurance system folds them into standard care once approved.

For patients and families researching options, the practical takeaway is simple: what is standard in one country may be years away in another. It is worth knowing where those gaps are.

The bigger pattern: prevention

Photoimmunotherapy is a dramatic example, but the wider gap is often quieter and more fundamental — in prevention. Japan’s comprehensive health screening tradition, the Ningen Dock, reflects a system built around finding problems early, before symptoms appear. That difference in philosophy is exactly what draws many people to look abroad for a more thorough baseline of their health.

We will keep tracking these developments — the drugs, procedures, and preventive approaches where Japan is ahead — here in The Mirai Journal each week.

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Sources: NCI Center for Cancer Research; Rakuten Medical press releases; Onco’Zine; U.S. Phase 3 trial NCT03769506.