With FDA Approval, Gefitinib Returns to U.S. Market for Some Patients with Lung Cancer
, by NCI Staff
Gefitinib, the chain-like structure, bound to the mutated epidermal growth factor receptor.
Last month, the Food and Drug Administration (FDA) approved gefitinib (Iressa®) for the initial treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have specific mutations in the gene for the epidermal growth factor receptor (EGFR).
The FDA also approved a companion diagnostic test, the therascreen EGFR RGQ PCR Kit, to test tumor samples for EGFR mutations and determine whether patients are candidates for treatment with gefitinib.
Gefitinib’s approval marks the drug’s return to the U.S. market. In 2003, based on a modest response rate in a clinical trial of patients with advanced lung cancer, gefitinib received accelerated approval from the FDA as a treatment for some patients with locally advanced or metastatic lung cancer.
Under accelerated approvals, however, companies must conduct additional trials to confirm initial indications of patient benefit. In 2011, after several trials failed to show that gefitinib improved outcomes for patients with lung cancer, AstraZeneca, the drug’s manufacturer, withdrew the drug in the United States.
This new approval is based on findings from two studies, including a recent 106-patient single-arm clinical trial that showed a 50 percent response rate in previously untreated patients whose tumors had specific EGFR mutations, as determined by the therascreen test.
Only four patients discontinued treatment because of side effects, the most common being rash, diarrhea, and vomiting.
The drug’s approval was also supported by findings from a subset analysis of an earlier randomized phase III clinical trial, called iPass, in patients with advanced lung cancer. Among patients in that trial whose tumors had EGFR mutations, those who were treated with gefitinib had substantially longer progression-free survival than those who were treated with standard chemotherapy.
Two other drugs are approved for the initial treatment of patients with advanced lung cancer whose tumors have the EGFR mutations: erlotinib (Tarceva®) and afatinib (Gilotrif®), both of which have been approved with companion diagnostic tests.
EGFR mutations are present in up to 15 percent of Caucasian patients and up to 50 percent of Asian patients. Gefinitib’s approval provides another option for clinicians and patients, said Shakun Malik, M.D., of NCI’s Division of Cancer Treatment and Diagnosis.