Biopharmaceutical company Geron's ( GERN) stock surged about 14% after the company said it was issued a U.S. patent for its cancer-destroying therapy, telomerase-based cancer immunotherapy. By early afternoon, shares of Geron were up 57 cents to $4.42 on the Nasdaq. The therapy, currently in Phase 1 human clinical trials, uses telomerase, an enzyme that is abnormally activated when tumors progress, to prepare a patient's immune system. Telomerase activation helps cancer cells resist cell death, which allows cells to grow and resist cytotoxic drugs. Geron's immunotherapy method works by telling the immune system to attack cells that contain telomerase. The new patent, which contains 22 claims, protects a specific telomerase-based immunotherapy approach. In it, antigen presenting cells, such as dendritic cells, are isolated from the patient and treated outside of the body either with antigenic fragments of the telomerase protein, or with nucleic acids that direct production of the telomerase antigen in the cells, the company said in a press release. The APCs then attack telomerase-positive cancer cells.