In studies to be published tomorrow in the New England Journal of Medicine, researchers report that the targeted therapies dramatically improved disease-free survival times in patients with pancreatic neuroendocrine tumors.
One of the phase III trials, involving Pfizer’s drug Sutent, was stopped early because the drug proved to be so effective.
In the other study, one out of three patients who took Novartis’ drug Afinitor had no evidence of tumor growth during 18 months of treatment, compared to one in 10 placebo-treated patients.
The time to cancer progression more than doubled in patients treated with Sutent or Afinitor compared to placebo, from about 5 months to 11 months.
An Uncommon Cancer
Neuroendocrine pancreatic tumors, also known as islet cell tumors, make up only about 1.3% of all pancreatic cancers.
These cancers are extremely uncommon -- occurring in just two to four people in a million -- but their incidence is rising.
Because they tend to grow and spread much more slowly than other pancreatic cancers, which have a very poor prognosis, patients with neuroendocrine pancreatic tumors can live for many years and can sometimes be cured with surgery.
“Most pancreatic cancer patients die pretty quickly, but patients with these tumors tend to do well for a very long time,” says David C. Metz, MD, co-director of the Neuroendocrine Tumor Center at the University of Pennsylvania Health System.
Metz says the Sutent and Afinitor studies are game changers for the treatment of the disease, but he adds that it remains to be seen if one drug works better than another or if a combination approach is best.
A similar kidney cancer drug, Bayer’s Nexavar, has also shown promise in the treatment of pancreatic neuroendocrine tumors.
“For the first time in 20 years we have a whole new group of drugs to treat this disease,” he tells WebMD. “The questions are, which ... drug do we use first and do we combine them. We don’t have the answers yet.”
The Sutent/Afinitor Studies
The Sutent phase III study was originally designed to include about 340 patients with advanced pancreatic neuroendocrine tumors taking either the drug or placebo. But it was stopped after only about half that number had been enrolled to allow the patients in the placebo arm of the study to switch to Sutent because the drug’s benefits were so obvious.
At the data cutoff point, nine deaths had been reported in the Sutent group (10%), compared to 21 deaths in the placebo group (25%).
The Afinitor trial included 410 patients treated with the drug or placebo until evidence of disease progression was seen, researcher James C. Yao, MD, of the University of Texas M.D. Anderson Cancer Center, tells WebMD.
After 18 months, 34% of the Afinitor-treated patients showed no evidence of disease progression, compared to just 9% of the placebo-treated patients.
Although both drugs were clearly effective, a significant number of patients reported troubling side effects, including a drop in infection-fighting white blood cells in 12% of those who took Sutent.
Yao says canker sores were the most commonly reported side effect in the Afinitor trial, with 64% of patients developing the sores at some point in treatment and 7% developing sores severe enough to cause problems eating and drinking.
In an editorial published with the studies, Robert T. Jensen, MD, of the NIH’s Digestive Disease Branch and Gianfranco Delle Fave, MD, of Italy’s University La Sapienza, write that it remains to be seen how the side effect profiles of the drugs will affect patient adherence.
“Drug-related side effects...are particularly important to consider, given that treatment will be long term and that many patients have an excellent quality of life with no treatment until late in the disease course, even with advanced disease that is progressive,” they write.
Data from both the studies, which were funded by the drugs’ manufacturers, were presented last summer at the 12th World Congress on Gastrointestinal Cancer in Barcelona, Spain.