American James Allison and Japanese Tasuku Honjo won the 2018 Nobel Prize in Medicine for discoveries leading to new approaches in harnessing the immune system to fight cancer, the award-giving body announced on Monday.

“Allison and Honjo showed how different strategies for inhibiting the brakes on the immune system can be used in the treatment of cancer,” the Nobel Assembly at Sweden’s Karolinska Institute said, on awarding 9 million Swedish crowns ($1.28 million Cdn).

Both laureates studied proteins that prevent the body and its main immune cells, known as T-cells, from attacking tumour cells effectively.

Honjo, who has been a professor at Kyoto University since 1984, discovered a protein on immune cells and revealed that it operated as a brake.

Therapy developed from Honjo’s research led to long-term remission in patients with metastatic cancer that had been considered essentially untreatable, the Nobel Assembly said.

Jimmy Carter a beneficiary

Former U.S. president Jimmy Carter, who had cancer that spread to his brain, was successfully treated with one of the drugs developed from Honjo’s work, said Jeremy Berg, editor in chief of the Science family of journals.

Allison, a professor at the University of Texas MD Anderson Cancer Centre, separately studied another protein that also functions as a brake on the immune system and realized the potential for unleashing immune cells to attack tumours if the brake could be released.

“The seminal discoveries by the two Laureates constitute a landmark in our fight against cancer,” the institute said.