Questions and Answers on
Iressa (gefitinib)
On June 17, 2005 the 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. For more, please read
the "Questions and Answers on
Iressa's (gefitinib) New Labeling" article.
Iressa (gefitinib) is a groundbreaking new type of anti-cancer drug for
people with the most common type of lung cancer. It is different from all
prior chemotherapy. That is, Iressa works by uniquely blocking cellular
enzymes that stimulate cell growth. So, in the future, look for the
emergence of other (hopefully more effective) anti-cancer drugs that work at
specific cellular or molecular sites.
With this approval by the Food and Drug Administration (FDA), patients
having advanced lung cancer that is unresponsive to standard treatment now
will have at least some treatment available to them. Credit the FDA for the
relatively rapid availability of this drug. You see, Iressa was approved
under the FDA's accelerated approval program. This program provides patients
with serious disease earlier access to promising new drugs.
Leslie J.
Schoenfield, M.D., Ph.D.
Medical Editor, MedicineNet.com
1. What is Iressa and how does it work?
Iressa is a new anticancer drug that inhibits an enzyme (tyrosine kinase)
present in lung cancer cells, as well as other cancers and normal tissues,
that appears to be important to the growth of cancer cells. The active
ingredient in Iressa is gefitibib.
2. What is Iressa used to treat?
Iressa is used as a single agent for the treatment of non-small cell lung
cancer (NSCLC) that has progressed after, or failed to respond to two other
types of chemotherapy (drugs used to kill cancer cells). Iressa is not
indicated as the first chemotherapy drug given (first-line therapy) for the
treatment of NSCLC because it has shown no benefit in two large,
well-controlled studies when used in that setting.
3. What is NSCLC?
Lung cancer is divided into two major classes: small cell lung cancer and
non-small cell lung cancer. NSCLC is the most common type of lung cancer,
accounting for almost 80% of lung cancers. There are five types of NSCLC, each
of which has different kinds of cancer cells. The cancer cells of each type
differ in size, shape, and chemical make-up, and grow and spread in different
ways.
4.
Is Iressa taken alone or is it taken in combination with other
chemotherapy drugs?
Iressa is taken alone, not with other chemotherapy.
5.
Is Iressa a cure for NSCLC?
In the third line setting, i.e., after failure of two other agents, Iressa
reduced tumor volume substantially in about 10% of people. There were no
cures.
6.
What is accelerated approval?
Accelerated approval is a program the FDA
developed to make new drug products available for life threatening diseases
when they appeared to provide a benefit over available therapy (which could
mean there was no existing effective treatment). Under this program, Iressa is
approved on the basis of early clinical study evidence (such as tumor
shrinkage) suggesting that the drug is reasonably likely to have a valuable
effect on survival or symptoms. The approval is granted on the condition that
the manufacturer must continue testing to demonstrate that the drug indeed
provides therapeutic benefit to the patient. If it does not, the FDA can
withdraw the product from the market more easily than usual.
7.
How many clinical trials were performed with Iressa and what did they
show?
The study on which FDA based it approval included 216 patients 139 of whom
had failed treatment with two other chemotherapy treatments. In this trial,
approximately 10% of patients responded to Iressa with a decrease in tumor
size.
The sponsor also presented to FDA the results of two large (about 1000
patients each) clinical studies with Iressa as initial therapy for lung
cancer. In these studies all patients received, standard combination
chemotherapy and were randomly given, in addition, either Iressa or a placebo.
In these studies there was no effect of Iressa on survival, time to further
growth of cancer, or on tumor size.
8.
Is Iressa approved in other countries?
Yes, Iressa is approved in Japan.
