TOKYO -- The 2018 Nobel Prize in Physiology or Medicine has been awarded jointly to immunologists James P. Allison of the U.S. and Japan's Tasuku Honjo for their "discovery of cancer therapy by inhibition of negative immune regulation," the Karolinska Institutet in Sweden announced on Oct. 1.

Honjo's discovery of Programmed Cell Death Protein 1 has led to major breakthroughs in cancer treatment, in a process whereby immune cells can be made capable of attacking cancer cells by blocking the PD-1 channel.

The two men had "established an entirely new principle for cancer therapy," said the official Twitter feed of the Nobel Prize.

"I am continuing my research for this immunotherapy to be able to save more cancer patients, and hope that it advances further with researchers all over the world working hard for that purpose," said Honjo at a news conference at Kyoto University, where he is distinguished professor at the Institute for Advanced Studies.

"It would be my greatest pleasure," if this award can "encourage people in fundamental research," after his own work led to a clinical application.

Therapies based on the discovery have proved effective in long-term cancer treatment and even resulted in cases of advanced recovery.

The awards ceremony will be held on Dec. 10 in Stockholm. The prize will be 9 million krona ($1 million).

Honjo's work led Ono Pharmaceutical to develop Nivolumab, a drug marketed as Opdivo that has proved successful in the treatment of various forms of cancer. It is also potentially effective in other areas, such as treating autoimmune diseases like arthritis.

Pharmaceutical companies around the world are striving to develop drugs and treatment methods based on the discovery.

Broadly speaking two major courses of research and development are being pursued. One is the development of new immunotherapy drugs, the other is its use in combination with existing immunological agents to enhance the effectiveness of cancer treatments.

In addition to Opdivo, there are four other major immunological anticancer agents that block the PD-1 channel -- Imfinzi, developed by U.K. maker AstraZeneca; Tecentriq by F. Hoffmann-La Roche of Switzerland; Keytruda, by U.S. company Merck; and Bavencio by the German maker Merck.

Other companies, such as Novartis International of Switzerland, are also developing similar products.

Japanese pharmaceutical players are generally focusing on combined use. Daiichi Sankyo has extensive expertise in antibody-drug conjugate technology, which combines monoclonal antibodies and cytotoxic molecules. The company plans to begin clinical tests on a combination of its DS8201 anticancer drug, now under development, and Opdivo.

Eisai and Kyowa Hakko Kirin are seeking ways of combining anticancer drugs they have developed with Opdivo.

Drug discovery venture businesses are also joining the race. In Japan, BrightPath Biotherapeutics, CanBas and Oncolys BioPharma are among the front-runners.

The combined use of medicines is aimed at making up for the limits of immunological anticancer agents, such as only being effective for certain patients.

Successful application of such combinations can result in huge profits for venture businesses, many of which currently operate in the red.

Analysts note that Japanese drugmakers have fallen behind in the market for biopharmaceuticals like immunological anticancer agents.

Data shows that four of the five biggest drugs in terms of sales are biopharmaceuticals. The biggest in 2016 was Humira, a treatment of rheumatoid arthritis produced by American drugmaker AbbVie, which chalked up over $17 billion in sales.

Chugai Pharmaceutical's rheumatoid arthritis treatment Actemra and Kyowa Hakko Kirin's anticancer agent Poteligeo are some of the biopharmaceuticals developed by Japanese companies. But neither logs sales of more than $10 billion.

Japanese companies have struggled to develop fundamental research into profitable applications.

In the field of regenerative medicines, such as the iPS cell technology credited to Shinya Yamanaka, a Nobel Prize-winning professor at Kyoto University, experts note that American and European companies are surging ahead of their Japanese counterparts when it comes to application research.