Advanced stage cancer patients with tumors that are inoperable or resistant to chemotherapy could soon be treated using near-infrared photoimmunotherapy (NIR-PIT), a promising technique likely to undergo a clinical trial in Japan as early as this year.

Preparation is under way for the clinical trial of the therapy developed by a Japanese researcher with a renowned U.S. health institution. It is expected to involve patients with head and neck cancers.

Hisataka Kobayashi, a doctor at the U.S. National Institutes of Health (NIH), told The Asahi Shimbun that the project’s aim is to ascertain the safety of NIR-PIT through clinical trials involving cancer patients in Japan.

The trial comes amid growing expectations that the new cancer immunotherapy will be put to practical use on advanced stage patients.

“NIR-PIT can give hope to patients with recurrent cancers,” Kobayashi said. “We are determined to spread the approach as an effective treatment to cure the disease.”

The therapy uses a specific antibody chemically joined to a photoabsorber, a molecule that absorbs light of a specific wavelength in the near-infrared part of the spectrum.

Kobayashi developed the antibody-photoabsorber combination, or conjugate, so that it is activated by near-infrared light only when bound to its target molecule.

Injecting the antibody-photoabsorber conjugate attaches it to cancer cells.

When near-infrared light is applied, the cancer cells swell rapidly and then burst. Their death activates a healthy immune system adjacent to the cells, giving an extra push in the body’s fight to destroy the cancer.

Near-infrared light, which causes no damage to humans, has been used in various devices such as TV remote controls.

A start-up contracted with the NIH has been conducting the first clinical trial of NIR-PIT in the United States since 2015, involving eight patients with recurrent head and neck cancers. Their cancers returned despite surgery or chemotherapy.

The results showed that three are still alive more than a year after receiving the new therapy with no tumors detected.

The remaining five patients have died, but doctors reported on the shrinkage of tumors in four of them.

None of the patients complained of serious side effects.

Kobayashi and his colleagues published their success in curing mice with cancer cells through NIR-PIT in a U.S. medical journal in 2011.

Kobayashi said he aims to put the therapy to practical use after gaining approval for it in the United States in 2019.

He envisages increasing the number of antibodies to eight so that NIR-PIT could be used to treat 80 to 90 percent of cancer patients.

The Japanese arm of the U.S. start-up will be involved in the planned clinical trial.