FDA关于Iressa的声明
The FDA today released the following statement regarding the failure of a clinical trial of Iressa (gefitinib) to show an overall survival advantage in treating patients with lung cancer:
The Food and Drug Administration (FDA) learned yesterday from AstraZeneca that a large clinical trial comparing Iressa (gefitinib) with placebo in patients with non-small cell lung cancer who had failed other courses of cancer therapy showed no survival benefit from taking Iressa.
Patients currently taking Iressa should consult with their physicians as soon as possible; patients should not change their therapy without first consulting with their physicians.
Alternative therapies are available. FDA has approved Taxotere (docetaxel) and Tarceva (erlotinib), both of which have been shown in studies to improve survival in patients with non-small cell lung cancer whose cancer has progressed while on previous therapies.
FDA approved Iressa on May 2, 2003, under the Agency's accelerated approval (Subpart H) program, for the treatment of patients with non-small cell lung cancer who had failed two or more courses of chemotherapy. The accelerated approval provisions in FDA's regulations allow the agency to approve a drug for marketing based on an effect on a surrogate endpoint -- such as a sign of a disease or the results of a laboratory test -- that is considered reasonably likely to predict clinical benefit (improved symptoms or survival). Iressa was approved because the data from clinical trials showed that it caused significant shrinkage in tumors in about 10% of patients, and this was thought likely to increase patients' overall survival time.
One requirement for drugs approved under the agency's accelerated approval program is that the sponsor must study them further after approval to verify the expected clinical benefit. After the approval of Iressa in 2003, AstraZeneca conducted a study in approximately 1700 patients to determine whether the drug would in fact prolong survival in comparison to patients taking placebo. The results announced today indicate that the drug did not prolong survival. Under FDA's accelerated approval program, the Agency has the authority to remove a drug from the market if a postmarketing clinical study fails to verify clinical benefit. After FDA has evaluated the recent study results, FDA will determine whether Iressa should be withdrawn from the market or if other regulatory actions are appropriate.