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Amgen says melanoma drug improved survival

THOUSAND OAKS, Calif. (AP) -- Amgen said Monday that patients treated with its experimental melanoma drug lived about four months longer than patients who were given an older treatment.

The results come from a late-stage trial of talimogene laherparepvec, or T-VEC. Amgen said patients who received T-VEC had median survival of 23.3 months, compared to 19 months for patients who were treated with granulocyte-macrophage colony-stimulating factor, or GM-CSF.

T-VEC is designed to be injected directly into tumor tissue, and it uses a virus as a Trojan horse to infiltrate and destroy tumors. The drug combines a gene snippet meant to stimulate the immune system with a modified version of the herpes simplex virus — the kind that causes mouth cold sores. After it is injected, T-VEC divides into copies repeatedly until the membranes, or outer layers, of the cancer cells burst, destroying them. Meanwhile, the gene snippet churns out a protein to stimulate a systemic immune response to kill melanoma cells in the tumor and elsewhere in the body.

Amgen reported positive results from the trial in March, showing T-VEC was more effective at making tumors disappear or shrink by at least half. In June, the company said the drug met its main goal, as a higher percentage of patients responded to treatment with T-VEC than GM-CSF.

There were more than 400 patients in the trial. Amgen said the most common side effects were fatigue, chills, and fever. The most common serious side effects of treatment with T-VEC included disease progression in both of their arms, skin infection, and fever. The company said serious side effects occurred in 26 percent of T-VEC patients and 13 percent of GM-CSF patients.

Amgen Inc. shares rose $1.05 to $116.03 Monday and were unchanged in aftermarket trading.