Aetna will now provide coverage for patients with metastatic prostate cancer who have failed to respond to hormone therapy and whose disease has spread to the lungs or the brain.

Previously, patients whose cancer spread to the brain or lungs were not covered. Patients whose disease has spread to the liver still are not covered.

Dendreon officials were not immediately available for comment.

Dendreon's shares rose 4.6 percent to $4.84 in afternoon trading on Nasdaq. Earlier in the day, they rose as high as $5.10.

Provenge, the first personalized, therapeutic vaccine to reach the market, has taken off to a disappointing start amid confusion among physicians over reimbursement. It costs roughly $93,000 per treatment.

In 2011, it generated just $213.5 million, roughly half of what the company had originally projected.

Provenge was approved in the United States in April 2010 and has been plagued by controversy ever since. Provenge extended median survival by 4.1 months, to 25.8 months from 21.7 months, in a clinical trial.

(Reporting by Toni Clarke; Editing by Leslie Adler)

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