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What is the FDA announcing?
The Food and Drug Administration (FDA) has approved new labeling for
gefitinib (Iressa) that limits use to patients with cancer who in
the opinion of their treating physician, are currently benefiting,
or have previously benefited, from Iressa treatment. In addition,
AstraZeneca will distribute the drug under the Iressa Access
Program
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Who can receive Iressa under the Iressa Access
Program?
Prescriptions for Iressa will be limited the following patient
populations:
- patients currently receiving and benefiting from
Iressa;
- patients who have previously received and benefited from Iressa;
and
- previously enrolled patients or new patients in
non-Investigational New Drug Application (non-IND) clinical
trials approved by an IRB (Institutional Review Board) prior to June
17, 2005.
Will any new patients be able to obtain Iressa?
New patients may be able to obtain Iressa under the Iressa Access
Program if they are eligible to participate in a non-Investigational
New Drug Application (non-IND)
clinical trial approved by an IRB prior to June 17, 2005. New
patients may also qualify for enrollment in clinical trials for
Iressa that are conducted under an IND.
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What is an IND?
An Investigational New Drug (IND) application is a submission from a
company that FDA uses to oversee clinical research and the use of
investigational drugs involving patients.
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When was Iressa first approved?
Iressa was approved for marketing in May 2003 under FDA’s
accelerated approval regulations (21 CFR part 314, subpart H).
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What are the accelerated approval regulations?
These regulations allow FDA to approve products that provide a
meaningful therapeutic benefit over existing therapies for serious
or life threatening illnesses on the basis of an effect on a
surrogate endpoint that FDA has determined is reasonably likely to
predict clinical benefit. Accelerated approval is granted on the
condition that the manufacturer must continue testing the drug in
clinical trials to demonstrate that the drug indeed provides
clinical benefit to the patient. If the studies fail to demonstrate
clinical benefit of the drug, or if the sponsor does not pursue the
confirmatory studies with due diligence, the FDA may withdraw the
product from the market more quickly than usual.
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What is a surrogate endpoint?
A surrogate endpoint is a laboratory finding or physical sign that
may not be a direct measurement of how a patient feels, functions,
or survives, but is still considered reasonably likely to predict
therapeutic benefit for the patient. In the case of Iressa,
accelerated approval was based on demonstration of response measured
by tumor shrinkage in approximately 10% of patients with non-small
cell lung cancer who had already received standard treatments.
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How was accelerated approval applied to Iressa?
Iressa was approved on the basis of a surrogate endpoint which was
approximately a 10% tumor response rate (tumor shrinkage) in
clinical studies in patients with advanced lung cancer. This tumor
response suggested that the drug was reasonably likely to have a
valuable effect on survival or symptoms.
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What is the reason for the Iressa Access Program?
FDA has carefully reviewed data from the completed clinical studies
of Iressa, including the confirmatory trial that was required by the
agency as part of the drug’s accelerated approval. The confirmatory
trial enrolled patients with advanced non-small cell lung cancer (NSCLC)
who had failed one or two prior chemotherapy regimens. In this large
study, 1,692 patients were randomly assigned to receive either
Iressa (gefitinib) or placebo. The results of the study showed no
significant survival benefit for those patients treated with Iressa.
Three other studies of Iressa in patients with lung cancer have also
failed to demonstrate improved survival. However, AstraZeneca
continues to examine the data and intends to pursue additional
clinical studies.
Other approved treatments for non-small cell lung cancer have been
shown to improve survival in clinical trials. Given the results of
these studies, it is not reasonable to start new patients on Iressa.
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What about patients who are already taking Iressa?
Patients who are currently receiving and benefiting from Iressa, or
who have taken and benefited from Iressa in the past, may continue
to receive the drug. The Iressa Access Program will allow those
patients continued access to Iressa. Previously enrolled patients or
new patients in non-IND clinical trials approved by an IRB
(Institutional Review Board) prior to June 17, 2005 are also
eligible to receive Iressa under the Iressa Access Program. Patients
enrolled or who may in the future enroll in a clinical trial
conducted under an IND may also continue to receive Iressa.
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Is this decision based on safety concerns?
The main concern is that Iressa would be used in new patients in
lieu of other approved treatments that have been shown to improve
patient survival. Since the approval of Iressa, Tarceva (erlotinib),
an oral drug similar to Iressa, has been approved for treatment of
patients with advanced NSCLC who have had prior chemotherapy.
Tarceva has been shown in clinical trials to significantly improve
patient survival. Taxotere, a chemotherapy drug, has also been shown
in clinical trials to improve survival in this group of patients.
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Has there been a limited access program for an
anticancer drug before?
No.
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Have other anticancer drugs received accelerated
approval and subsequently been withdrawn from the market or made
available in a limited access program? If so, what are they?
No.
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Will Iressa eventually be pulled completely from the
market?
The FDA is not currently considering withdrawal of Iressa. When the
number of patients receiving Iressa under the limited access program
becomes small, Iressa may either be removed from the market or,
depending on any additional clinical data, the indication may be
modified. There are ongoing clinical trials and other clinical
trials are planned that may support approval of Iressa for a new
indication. If Iressa is eventually withdrawn from the market, the
FDA will consider authorizing continued Iressa access under an IND
protocol for patients who are benefiting or have benefited from
Iressa.
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What are other treatment options for NSCLC?
Tarceva and Taxotere have been shown to prolong survival in patients
with advanced NSCLC who have had prior chemotherapy. Alimta has also
been granted accelerated approval for treatment of these patients.
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What impact does Tarceva have?
Tarceva prolonged life by an average of 2 months in patients with
advanced NSCLC who had received one or two prior chemotherapy
regimens.
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How are Tarceva and Iressa similar?
Tarceva and Iressa are similar drugs. Both are targeted therapies.
Both are EGFR tyrosine kinase inhibitors.
