Swiss drugmaker Roche Holding AG announced Friday that new data from a study with Herceptin showed impressive results in helping women with advanced, HER-2 positive metastatic breast cancer to live longer without their cancer progressing.

The data coming from a randomized phase III GBG-26 study were presented at the American Society of Clinical Oncology annual meeting in Chicago. According to these data, a mixture of Herceptin, also known as trastuzumab, and chemotherapy treatment Xeloda halted the progress of breast tumors for almost three months longer than treatment with Xeloda alone. Moreover, continuation of Herceptin nearly doubled the percentage of patients responding to treatment from 27 percent to 48 percent.

Herceptin, approved in 1998, is a humanized antibody designed to target and to block the function of HER2, a protein produced by a specific gene with cancer-causing potential. In cases of HER-2 positive metastatic breast cancer, tumors tend to grow faster and are more likely to recur than tumors that do not carry the protein.

More than 1 million new cases of breast cancer are diagnosed worldwide, and nearly 400,000 people will die of the disease annually, the company said. HER2-positive breast cancer affects approximately 20 percent to 30 percent of women with breast cancer.

Herceptin is becoming more and more widely used to fight breast cancer, as it is now used on more than 450,000 patients worldwide.