Another expert said the therapy, while far from a cure, "looks promising." Speaking at the time of the drug's approval by the CMS panel, Dr. Elizabeth Kavaler, a urologist at Lenox Hill Hospital in New York City, said that "in this unfortunate category of [hormone-resistant] patient, we have very little to offer. Adding months to a man's life is better than doing nothing, especially if the treatment involves minimal morbidity, as this vaccine promises."
The U.S. Food and Drug Administration approved Provenge in April 2010 for the treatment of prostate cancer that has spread to other parts of the body and is resistant to standard hormone treatment.
In his team's study, Kantoff's group randomly assigned 512 men to receive Provenge or a placebo. All of the patients had advanced prostate cancer that had proven resistant to standard hormonal therapy.
On average, men receiving Provenge lived 4.1 months longer than men receiving a placebo, the researchers found. Average survival was 25.8 months for men in the Provenge group, compared with 21.7 months for men in the placebo group, meaning that Provenge extended survival by 22 to 25 percent, Kantoff said.
He contends that if the vaccine were used by men with less severe disease, survival might be extended even longer.
"Theoretically, if you take people with less disease and you stimulate the immune system, you could have a more profound effect, but we don't really know that yet," he said.
Compared with other treatments, such as chemotherapy, radiation and hormone therapy, Provenge has been touted as having fewer and less severe side effects. In this trial, the most common side effects were chills, fever and headache, the researchers noted.
Commenting on the high cost of Provenge, Kantoff s
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