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FDA
Public Health Advisory
New Labeling and Distribution Program for Gefitinib (Iressa)
The Food and Drug Administration (FDA) has approved
new labeling for gefitinib (Iressa) that limits the indication to
cancer patients, who, in the opinion of their treating physician,
are currently benefiting, or have previously benefited, from
gefitinib treatment. The FDA has agreed to AstraZeneca's proposal to
limit distribution of this drug under a risk management plan called
the Iressa Access Program, to the following patient populations:
-
patients currently receiving and benefiting from
Iressa;
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patients who have previously received and benefited
from Iressa; and
-
previously enrolled patients or new patients in
non-Investigational New Drug (IND) clinical trials approved by an
IRB prior to June 17, 2005.
New patients may also be able to obtain Iressa if
AstraZeneca decides to make it available under IND and the patients
meet the criteria for enrollment under the IND.
Gefitinib, an orally administered epidermal growth
factor receptor (EGFR) tyrosine kinase inhibitor, was approved for
marketing in May 2003 for patients with non-small cell lung cancer
under Subpart H accelerated approval regulations that allow products
to be approved on the basis of a surrogate endpoint for clinical
efficacy. For gefitinib the surrogate end-point was tumor response
rate. The response rate in patients taking the drug was
approximately 10%. The approved indication was for the treatment of
patients who were refractory to established cancer treatments (both
a platinum drug and docetaxel). However, since the initial approval
of Iressa, Tarceva (erlotinib) has been approved for treatment of
this same group. Tarceva was approved based on improved overall
survival.
FDA has carefully reviewed data from two failed clinical studies of
Iressa, one of which was required by the agency as part of the
drug’s accelerated approval. This trial enrolled patients with
regionally advanced or metastatic NSCLC who had failed one or two
prior treatment regimens. In this large study, 1,692 patients were
given either gefitinib or placebo. There was no significant survival
benefit in the overall study population nor in patients who had high
levels of a surface marker called “EGFR.” In contrast, the presence
of EGFR at high levels appears to predict a good response to Tarceva.
In the second trial in patients with stage III NSCLC, after
completion of induction and consolidation chemotherapy and radiation
therapy, patients were given either gefitinib or placebo maintenance
therapy. No gefitinib survival benefit could be demonstrated.
The Food and Drug Administration is not considering market
withdrawal of gefitinib at this time. New clinical trials are being
developed, other ongoing trials are being completed, and there will
be further analysis of the completed trials described above. These
will determine the future role of gefitinib treatment.
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Date created: June 17, 2005 |
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