An experimental drug by German drug maker Bayer and Onyx Pharmaceutical Inc has improved the overall survival by 29 percent in patients suffering from colorectal cancer, who have run out of standard treatment options.

Results from the late-stage trial involving 760 patients across the U.S., Europe, Japan, Australia and China showed that the drug, regorafenib, helped patients with metastatic colorectal cancer live a median time of 6.4 months, compared with a median of 5 months for those in the placebo group.

However, like all almost other cancer drugs, regorafenib too, had significant side effects like severe skin reactions, fatigue and diarrhea.

Results from the study will be presented at the Gastrointestinal Cancers Symposium of the American Society of Clinical Oncology Jan. 21.

Colorectal cancer is the third most common cause of cancer death in the U.S. and almost 140,000 cases of colon cancer are expected to occur this year. The American Cancer Society predicts that about 52,000 American will die from colon cancer this year, accounting for almost 9 percent of all cancer death.

If approved, regorafenib is expected to generate billion dollars in sales and offer alternative treatment option to patients beyond existing drugs like Eli Lilly's cetuximab (Erbitux), Roche's bevacizumab (Avastin), and Amgen's panitumumab (Vectibix). Bayer will also pay a royalty of 20 percent to Onyx on the drug's sales.

Bayer said it would seek marketing approval for the treatment of colorectal cancer that spread to the other part of the body later this year.