Data published online and in an upcoming print issue of The Lancet show that Glivec (imatinib), when taken after surgery, substantially reduces the rate of recurrence of Kit positive gastrointestinal stromal tumors (GIST) compared with placebo.
The Phase III study published today was led by the American College of Surgeons Oncology Group (ACOSOG) and examined post surgery, or adjuvant, treatment of more than 700 GIST patients. Researchers found that 98% of patients receiving 400 mg of Glivec daily remained tumor-free one year after surgery. The study also found Glivec to be safe and well-tolerated, with a low rate of serious adverse events.
GIST is a life threatening cancer of the gastrointestinal tract. After initial surgery to remove the tumor, GIST can return in one of two patients within a median of two years.
“The standard of care after surgical removal of primary GIST has been clinical and radiologic observation, since standard chemotherapeutic agents have been ineffective in this disease. This frequently resulted in tumor recurrence,” said Ronald DeMatteo, MD, Memorial Sloan Kettering Cancer Center, New York, NY. “Now, as The Lancet reports, by treating patients with Glivec after removal of their initial tumor, we can proactively impact the course of this disease by delaying, and in some patients possibly preventing, the return of the cancer.”
Glivec was recently approved in the US, Switzerland and several other countries for the treatment of GIST in the adjuvant setting, based on the ACOSOG data. This approval represented the tenth indication for Glivec in the US.
The double blind, randomised, multi centre study was conducted throughout the US and Canada. It included 713 GIST patients whose tumors had been surgically removed. The study compared the recurrence free survival (RFS) of patients taking either Glivec 400 mg daily or placebo immediately following surgery. The results showed that 98% of those receiving Glivec remained recurrence-free one year following surgery compared with approximately 83% of those receiving placebo (P<0.0001).
The investigators reported that Glivec therapy was well tolerated by most patients, with side effects similar to those observed in previous clinical trials with Glivec. These include nausea, diarrhea and swelling (edema).
Gastrointestinal stromal tumors (GIST) belong to a group of cancers known as soft tissue sarcomas. The most common sarcomas, they can be found most often in the stomach and small bowel. In the EU, the incidence of GIST is estimated to be more than 5,000 cases per year, of which approximately 95% are Kit-positive. Median time to recurrence is approximately two years. Kit (also known as CD117) is the protein that, when mutated, has been identified as one of the major causes of GIST. Glivec inhibits the activity of several proteins, including Kit.