The U.S. Food and Drug Administration (FDA) has approved the angiogenesis inhibitor sunitinib (Sutent) to treat a rare and challenging form of pancreatic cancer called a neuroendocrine tumor (NET). Sunitinib is a pill that blocks tumor blood vessel growth (angiogenesis), a critical process in cancer development, progression, and metastasis. The FDA decision makes sunitinib the first antiangiogenic agent to be approved for the treatment of pancreatic NET.
Approval of sunitinib was based upon positive results from a phase 3 clinical trial involving 171 patients with advanced, inoperable pancreatic NET. The study was stopped early when it became apparent that patients receiving sunitnib were living significantly longer without their disease getting worse, a measure of benefit called progression-free survival (PFS), compared with patients who got a placebo. Patients who received sunitinib had a PFS of 10.2 months, while those who got placebo had a PFS of only 5.4 months. At the time of the final study analysis, 9 patients in the sunitinib arm of the study had died, compared with 21 in the placebo group.
Separately, an FDA cancer panel voted unanimously to approve another angiogenesis inhibitor called everolimus (Afinitor) for the treatment of advanced pancreatic NET. Everolimus works differently from sunitnib by blocking a protein called mTOR that is involved in both tumor growth and angiogenesis. In a placebo-controlled phase 3 study, everolimus more than doubled median PFS versus placebo, from 4.6 months to 11.0 months.
Although pancreatic neuroendocrine tumors comprise only about 5% of all pancreatic cancers, they are difficult to treat once the disease has spread to other parts of the body, and there have been few new therapies in recent decades. In patients with advanced disease, only 30-40% remain alive 5 years after diagnosis. Patients typically receive some combination of surgery, hormone therapy, radiation, and chemotherapy depending on the stage of the cancer. Pancreatic NET is highly dependent on angiogenesis, so the approval of an angiogenesis inhibitor represents a major step forward in the treatment of this cancer.