The U.S. Food and Drug Administration (FDA) has approved Iressa (gefitinib) for the first-line treatment of patients with metastatic epidermal growth factor receptor (EGFR) mutation-positive non-small cell lung cancer (NSCLC).
“Iressa offers another effective first-line therapy option for selected lung cancer patients. This approval provides further support for a highly targeted approach to treating cancer,” said Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research.
Gefitinib is a tyrosine kinase inhibitor that inhibits proteins that promote that development of cancerous cells with EGFR exon 19 deletions and exon 21 L858R substitution gene mutations.
The FDA also approved a companion diagnostic test, therascreen EGFR RGQ PCR Kit, to identify patients whose tumors possess the EGFR mutations that would determine which patients would benefit from treatment with gefitinib.
“The approval of the therascreen EGFR RGQ PCR Kit will allow physicians to identify non-small cell lung cancer patients who are candidates for receiving Iressa as first-line therapy,” said Alberto Gutierrez, PhD, director of the Office of In Vitro Diagnostics and Radiological Health in the FDA’s Center for Devices and Radiological Health. “Companion diagnostics provide information that is essential for the safe and effective use of important medications.”
The FDA’s approval of gefitinib in this patient population is based on a multicenter, single-arm clinical trial of 106 treatment-naive patients with EGFR mutation-positive metastatic NSCLC. Results showed that gefitinib 250 mg once daily shrank tumors in about 50% of patients with a mean duration of response of 6 months.
In regard to safety, gefitinib can cause serious side effects such as gastrointestinal perforation, interstitial lung disease, liver damage, ocular disorders, and severe diarrhea, however the most common treatment-related adverse events are diarrhea and skin reactions.