September 25, 2014 1:00 pm JST
TOKYO -- Researchers at Japan's Keio and Osaka universities together with the National Cancer Center have had success with trials conducted on effective immune therapy for the treatment of certain types of cancer in conjunction with existing anti-cancer drugs.
They will announce the findings at the 73rd Annual Meeting of the Japanese Cancer Association to be held in Yokohama from Sept. 25.
Enhancing inner strength
Immune therapy is a treatment that destroys cancer cells by taking advantage of immune system. It has fewer side effects than existing anti-cancer drugs. Currently the mainstream approach is to take Tcells, a type of immune system cell, from a patient and then return the cell to the same patient after enhancing its functions.
Immune therapy started in the 1970s, but its effectiveness remained ambiguous for a long time. But lately, clinical trials are providing scientific evidence of treatment's effectiveness. Now immune therapy is emerging as the fourth cancer treatment following three established treatments -- surgery, irradiation and chemotherapy.
The therapy has only been confirmed as effective for a limited numbers of cancers, such as melanoma and prostate cancer. Even so, due to its tendency to prevent against tolerance development and its long lasting effect, there are great hopes for it to become a major treatment.
"(Immune therapy is) promising because it may support various cancer treatments in the future," said Hisafumi Okabe, vice president and general manager of the research division at Chugai Pharmaceutical.
But the efficacy and side effects vary significantly depending on the individual because "Each patient has a different number and types of Tcells," said Keio University Professor Yutaka Kawakami.
Also, Alsoimmune therapy becomes less effective due to the ability of cancer cells to suppress immunity. The new immune therapy focuses on preventing cancer cells from having this ability.
Combining regular medicines
A group led by Keio University's Kawakami discovered that combining two types of over-the-counter drugs will improve the workings of immune cells. The group administered the Nivolumab melanoma treatment drug developed by Ono Pharmaceutical together with anti-cholesterol drug statin to ovarian cancer cells and discovered the possibility of an increase in Tcells and of enhancing statin's offensive power.
The melanoma treatment drug is an antibody that adheres to the protein on the surface of Tcells. The drug prevents cancer cells from avoiding attacks from immune cells.
Kawakami says, "Using the two types of drugs may be effective to the patients for whom the Nivolumab didn't work well."
Another group led by Osaka University Associate Professor Hiroyoshi Nishikawa has found a substance that destroys the "shield" of cancer cells used to defend against attacks from immune cells.
The group used the Mogamulizumab lymphoma treatment drug developed by Kyowa Hakko Kirin. When the antibody attacks the shield, made up of regulatory Tcells, the number of Tcells roughly tripled and became more active.
The group confirmed the efficacy of this action on cancer cells taken from 30 melanoma patients. They will also study whether it works on stomach, bowel and lung cancers.
The other group led by Dr. Shigehisa Kitano of the National Cancer Center Hospital used the Ipilimumab melanoma treatment drug developed by American company Bristol-Myers Squibb, for which is awaiting sales approval from the Japanese government.
The drug also adheres to the protein on the surface of Tcells and was known to be capable of enhancing the offensive power of T-cells. But it was newly found that the drug was also assisting helper Tcells to attack cancer cells directly.
The group confirmed the efficacy of the drug for melanoma patients for whom surgery cannot be performed. Also, using the Ipilimumab with other drugs that increase the number of Tcells is thought to boost effectiveness.
(Nikkei)
