TOKYO – Japan, with the world's third-highest rate of stomach cancer behind Mongolia and the Republic of Korea, will soon have another combination drug mix to help treat the disease.

Tokyo-based Chugai Pharmaceutical Co. Ltd. has filed for approval of Xeloda (capecitabine) to be used in combination with Yakult Honsha Co. Ltd.'s Elplat (oxaliplatin) for gastric or stomach cancer in after-surgery chemotherapy. The drugs are most commonly used in combination after surgery to kill any cancer cells that have been left behind but are too small to see.

Stomach cancer is the fifth most-common cancer in the world, with 952,000 new cases diagnosed in 2012, according to the World Cancer Research Fund International.

"We are applying for approval in order to assist gastric cancer patients," a Chugai spokesperson told BioWorld Today. "We believe that Xeloda will make a contribution to patients as a treatment option for postoperative adjuvant chemotherapy for gastric cancer."

Adjuvant therapy is given after primary treatment to minimize the risk that the cancer will return. It may include chemotherapy, radiation therapy, hormone therapy, targeted therapy or biological therapy.

Xeloda was developed by Nippon Roche K.K. (now Chugai), and it received its first regulatory approvals in the U.S., Switzerland and Canada in 1998 and in the EU in 2001. The drug has been approved by more than 100 countries and has been used in more than 1.5 million patients as a standard treatment for metastatic breast cancer, colon cancer and advanced gastric cancer.

On average, there are about 60 cases of stomach cancer per 100,000 residents in Japan. The Japan Cancer Society reported that in 2007, one in every three deaths was attributed to stomach cancer.

Since 1945, as many as 50,000 to 60,000 Japanese have died from some form of cancer each year. With prevalence so high for stomach cancer in Japan, researchers are aiming to find the cause, noting similarities among Asian cuisines. The primary sources of prevention provided to the Japanese are nutritional education, screening and early detection.

"The issue of why Japan has such a high incidence of stomach cancer has been talked about for a long time," said Reed Maurer, a veteran Japanese pharmaceutical industry watcher, president of International Alliances Ltd. and chairman of Rigen Pharmaceuticals. "Is it the diet or are there other reasons for it? The fact is that we have not seen anything definitive on it. We just don't know."

Chugai will also file for approval of Kadcyla (trastuzumab emtansine), an antibody-drug conjugate that was approved in 2013 for the treatment of HER2-positive inoperable or elapsed breast cancer, for an additional indication of gastric cancer.

In 2016, the drugmaker will file a new application for glycol-engineered, type II anti-CD20 monoclonal antibody Gazyva (obintuzumab) for the treatment of aggressive non-Hodgkin's lymphoma and RG7446, an anti-PD-L1 antibody, for non-small-cell lung cancer.

Chugai, established in 1943, manufactures and sells pharmaceuticals in the domestic and international markets through its subsidiaries. The company develops drugs in the fields of cancer, infectious diseases, bone, blood and circulatory systems. Chugai also conducts research studies on drugs with private and public medical research institutions. The company has more than 6,800 employees and revenue of ¥423.7 billion (US$3.5 billion).

Chugai noted that Xeloda is a clinically useful oral cancer drug with an evidence-based efficacy for postoperative adjuvant chemotherapy for colon cancer. Patients that used the drug were found to be disease-free and had an overall survival rate equivalent to patients treated with the global standard treatment 5-FU/LV.

The drug, which is hydrolyzed by an enzyme in the liver or tumor tissue, also was approved for use for inoperable or recurrent breast cancer.

According to Chugai's website, the company "places high importance on oncology as one of its strategic therapeutic domains."

Multinational biopharma company Roche AG owns a 62 percent stake in Chugai. In August, the multinational decided against bidding to acquire the remaining stake in the company. That decision led to a single-day drop of 9.1 percent of Chugai's shares on the Tokyo stock exchange (TYO:4519), the biggest such drop since March 2011.