Immunotherapy Drug (MPDL3280A) Shows Promise against range Of Cancers

 An experimental Roche Holding AG drug that helps the immune system attack tumors was well tolerated and demonstrated an impressive effect against a variety of cancers, according to preliminary trial results released on Wednesday. While clinical testing of the drug is still in its early phases, the Roche treatment is considered one of the most promising in a new class of immunotherapies being developed by global drug makers. The drug, called MPDL3280A, significantly shrank tumors in 21 percent of 140 patients with advanced melanoma, lung cancer or kidney cancer, according to data from a scientific abstract of the Phase I study. Of the 29 patients whose cancer responded to the drug, 26 continued to respond - some more than a year after starting treatment - researchers said. Roche's drug is an engineered antibody that targets a protein called PD-L1 on cancerous tumors, a defense mechanism that tumors use to trick the immune system's T cells into remaining inactive. Once the T cells can recognize the cancer, they grow and multiply to more efficiently attack it. Broken down by cancer type, the response rate so far has been 31 percent in melanoma, 22 percent in lung cancer and 13 percent in kidney cancer, the available data showed. The study has since been expanded to include patients with colon, bladder and head and neck cancers, researchers said.