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Imatinib Approved for Post-surgery Treatment of Gastrointestinal Stromal Tumors
Glivec is now the only post-surgery treatment indicated to delay the return of this highly aggressive cancer, filling a major need for GIST patients. The filing received FDA priority review status in August of this year, with regulatory reviews currently underway in other regions, including the European Union and Switzerland.
GIST is a life-threatening cancer of the gastrointestinal tract. After initial removal, GIST tumors can return in as many as one of two patients. Recurrent GISTs are often more aggressive than primary tumors, with relapses associated with lower survival rates.
"After surgery, my doctor told me there was a high likelihood that my gastrointestinal tumors would come back. I immediately searched for a possible solution and found the Glivec clinical trial, which aimed to help patients like me," said Roslyn Fuller, a GIST patient. "This FDA approval is good news for me and other GIST patients who will now have the option to start treatment with Glivec earlier to help prevent recurrence."
The approval for this new indication is based on data from a National Cancer Institute-sponsored Phase III study that showed a dramatic reduction in the return of GIST after surgery in patients treated for about one year with Glivec versus placebo. Based on a 14-month median follow up, 91.6% of Glivec patients remained cancer-free compared with 80.2% of those taking placebo.
"When Glivec was first approved for the treatment of inoperable and/or metastasized Kit-positive GIST six years ago, it revolutionized the treatment of this life-threatening cancer," said David Epstein, President and CEO, Novartis Oncology. "This latest FDA approval means patients can benefit from Glivec earlier in the course of their disease."
Glivec is now approved for nine indications, including the treatment of Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML), Kit (CD117)-positive gastrointestinal stromal tumors which cannot be surgically removed and/or have already spread to other parts of the body (metastasized) and five other rare diseases.
The FDA regulatory filing for the adjuvant GIST indication was based on data from a Phase III, double-blind, randomized, multicenter, international study of more than 700 GIST patients who had undergone surgery to remove their tumors. The efficacy endpoint of the study was recurrence-free survival (RFS), defined as the time from the date of randomization to the date of recurrence or death from any cause. Participants were randomized to receive either Glivec 400 mg/day or a matching placebo for one year.
With a median follow-up of 14 months, there were 30 RFS events out of 359 patients in the Glivec arm (8.4%) compared to 70 RFS events out of 354 patients in the placebo arm (19.8%) (hazard ratio=0.398 [95% CI: 0.259, 0.610], p The investigators reported that Glivec therapy was generally well tolerated by most patients, with side effects similar to those observed in previous clinical trials with Glivec. The most frequently reported adverse reactions were diarrhea, fatigue, nausea, edema, decreased hemoglobin, rash, vomiting and abdominal pain. No new adverse reactions were reported in the adjuvant GIST treatment setting that had not been previously reported in other patient populations including patients with unresectable and/or malignant metastatic GIST.
About gastrointestinal stromal tumors
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 intestine. The incidence of GIST is estimated to be 4,500 - 6,000 new cases per year in the US (15-20 cases per million population), of which more than 90% are Kit-positive. Kit - also known as CD117 - is a protein that, when mutated, has been identified as one of the major causes of GIST. Glivec inhibits the activity of several proteins such as Kit.