The label now includes a black box warning that it can increase the risk of death, MI, stroke, venous thromboembolism, thrombosis of vascular access, and tumor progression or recurrence.

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But the approval may not be a sure thing, according to Daniel Petrylak, an oncologist at Columbia University Medical Center, because Dendreon's studies did not meet their main pre-specified goal: a slowing of tumor progression.

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You are freezing the tumor and delaying the progression of the disease.

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"Kadcyla delivers the drug to the cancer site to shrink the tumor, slow disease progression and prolong survival, " said Dr. Richard Pazdur, director of the Office of Hematology and Oncology Products in the FDA's Center for Drug Evaluation and Research, in a statement.

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