For the first time, the Food and Drug Administration has approved a new cancer drug for use in two different diseases – advanced kidney tumors and rare abdominal malignancies.
Sutent, approved Thursday, doesn't cure cancer, but experts say it is an important advance – both for patients and for science.
Sutent, made by Pfizer, is the second drug in only about a month to treat advanced kidney cancer, a disease for which there were no new therapies for more a decade, according to the FDA, which approved a Bayer drug called Nexavar in December. Although studies have not yet shown that Sutent improves survival, the agency granted Sutent accelerated approval because kidney cancer is so deadly.
Sutent shrank tumors in 26% to 37% of patients, according to the FDA. That makes it far safer and more effective than older drugs for the disease, which are so risky that they are often given in an intensive care unit. About 36,000 cases of kidney cancer are diagnosed each year and 12,600 die of it, according to the American Cancer Society.
Pfizer plans to continue studying Sutent, and is testing it in cancers of the breast, colon, lung and other organs, says Joseph Feczko, the company's chief medical officer.
Sutent belongs to a new wave of "smart drugs," says George Demetri, who helped develop Sutent and directs the Center for Sarcoma and Bone Oncology at the Dana-Farber Cancer Institute in Boston.
Sutent is able to combat two types of tumors because both cancers are fueled by the same defective proteins, Demetri says.
Unlike chemotherapy, which poisons all growing cells, drugs such as Sutent are designed to block the spread of tumors but largely spare healthy tissue, says Demetri, who presented a study of Sutent at a medical conference in San Francisco Thursday.
Sutent also combines two powerful strategies to fight cancer, Demetri says. It silences growth signals inside cancer cells and also also cuts off their blood supply.
And Demetri notes that Sutent is the first targeted therapy approved to take over where another smart drug has left off.
In addition to kidney cancer, the FDA approved Sutent for patients with gastrointestinal stromal tumors, or GIST, whose disease is no longer controlled by a drug called Gleevec, or who had rare but severe reactions to it. About 5,000 people are diagnosed with GIST every year, according to the FDA.
Gleevec was one of the first drugs designed to disable specific growth signals inside cancer cells. It extended the median survival of GIST patients from nine months to five years, says Michael Heinrich, a professor at Oregon Health & Science University.
But tumors are adaptable. Over time, they develop mutations that allow them to get around even powerful drugs such as Gleevec, Demetri says. About half of GIST patients develop resistance to Gleevec in only about two years.
Sutent works by blocking the proteins that make tumor cells immune to Gleevec, Demetri says.
In a carefully designed trial of more than 300 patients, in which some got Sutent and some took placebos, Sutent cut the risk of death by more than half, according to Demetri's study. Sutent also kept tumors in check for six months. Among patients who took placebos, their tumors began growing again in only six weeks.
Controlling these tumors for six months may seem like a modest achievement. But Paul Mansfield of M.D. Anderson Cancer Center, who was not involved in the Sutent study, notes that patients in the study had very advanced disease and no other options for treatment.
Sutent's major side effects include fatigue, diarrhea, nausea and mouth sores, although these problems rarely were serious enough to make patients stop taking the drug, according to the study.
Promising news for esophageal cancer
Researchers at the San Francisco conference also presented promising news about esophageal cancer, a disease that kills 85% of patients within five years.
Patients with early-stage disease who underwent surgery, chemotherapy and radiation lived more than twice as long as those treated with surgery alone, says Mark Krasna, a professor at the University of Maryland. Those who got the triple therapy lived about 4.5 years, while other patients survived only 1.8 years.
Krasna says more patients could benefit from triple therapy. Only about one-third of esophageal cancer patients today receive the combination. Another third of patients today are treated with surgery alone, Krasna says.
The study's findings are significant, even though researchers only studied 56 patients, says Leonard Gunderson, a professor at the Mayo Clinic in Scottsdale, Arizona. Researchers had hoped to enroll more patients, but closed their trial early when too few people enrolled, largely because so many people hoped to benefit from triple therapy.
