The US Food and Drug Administration (FDA) has granted imatinib full approval as an adjuvant treatment following surgical removal of CD117-positive gastrointestinal stromal tumors (GIST) in adult patients. The drug had received accelerated approval for this indication in 2008.
The confirmatory, phase III study that led to the approval showed that patients taking imatinib for 36 months had a 5-year overall survival of 92%, compared with 82% for those who only took the drug for the standard 12 months of treatment.
“The development of Gleevec over the past decade highlights the need to further study drugs after approval to truly characterize their benefits,” said Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, in a press release announcing the approval.
Imatinib was first approved in 2001 for the treatment of chronic myeloid leukemia for Philadelphia chromosome–positive patients.
In 2002, imatinib was granted approval for the treatment of advanced or metastatic GIST. The accelerated approval for adjuvant use in patients with resectable GIST was granted in 2008.
“Although originally approved in the metastatic disease setting, this subsequent trial has demonstrated that longer use of Gleevec can prolong patients’ lives in earlier disease settings,” added Pazdur.
Data from the international, multicenter, phase III trial showed that 36 months of imatinib prolonged recurrence-free survival (RFS) compared to 12 months, resulting in a 54% reduction in the risk of recurrence (P < .0001). In addition, 36 months of imatinib treatment resulted in a 55% reduction in the risk of death compared to 12 months of treatment (P = .0187).
The most common adverse events observed in patients receiving imatinib include edema, bone or muscle pain, diarrhea, rash, nausea, vomiting, muscle cramps, fatigue, and abdominal pain.
Imatinib is marketed by Novartis.