Name: Iressa

Do I need a prescription for gefitinib?



Store at room temperature between 68 and 77 degrees F (20-25 degrees C) away from light and moisture. Do not store in the bathroom. Keep all medicines away from children and pets.Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company for more details about how to safely discard your product.

Reviewed on 4/16/2014 References

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  • Astrazeneca

Iressa Drug Class

Iressa is part of the drug class:

  • Protein kinase inhibitors

Iressa Usage

Iressa is a tablet to be taken by mouth, with our without food, usually once a day.

Take Iressa at around the same time every day.

Follow the directions on your prescription label carefully and take this medicine exactly as prescribed by your doctor. 

If you miss a dose take it as soon as you remember unless it is almost time for your next dose. 

If you have difficulty swallowing tablets, you may dissolve Iressa tablets in water. No other liquids should be used. Drop the tablet in the water, without crushing it, stir until the tablet is dispersed (approximately 10 minutes) and drink the liquid immediately. Rinse the glass with half a glass of water and drink. The liquid can also be administered through a naso-gastric tube.

Iressa is not available in pharmacies. You can only get Iressa through a distribution program that has been set up by the manufacturer for people who have taken Iressa in the past. You will need to sign a consent form before you receive any medication. You will receive your medication by mail from a specific mail order pharmacy. Ask your doctor if you have any questions about receiving your medication.

Other Interactions

Certain medicines should not be used at or around the time of eating food or eating certain types of food since interactions may occur. Using alcohol or tobacco with certain medicines may also cause interactions to occur. Discuss with your healthcare professional the use of your medicine with food, alcohol, or tobacco.

What is the most important information I should know about gefitinib?

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

What should I discuss with my healthcare provider before taking gefitinib?

You should not use gefitinib if you are allergic to it.

To make sure gefitinib is safe for you, tell your doctor if you have:

  • liver disease;

  • kidney disease;

  • vision problems;

  • breathing problems, lung disease other than lung cancer; or

  • if you take a blood thinner (warfarin, Coumadin, Jantoven).

Do not use gefitinib if you are pregnant. It could harm the unborn baby. Use effective birth control to prevent pregnancy while you are using this medicine and for at least 2 weeks after your treatment ends.

This medicine may affect fertility (the ability to have children) in women. Tell your doctor if you plan to become pregnant.

It is not known whether gefitinib passes into breast milk or if it could harm a nursing baby. Do not breast-feed while taking gefitinib.


  • Inhibits intracellular phosphorylation of numerous tyrosine kinases associated with transmembrane cell surface receptors, including epidermal growth factor receptor (EGFR) tyrosine kinase;1 2 3 4 activation of EGFR tyrosine kinase may initiate cascade of intracellular signaling events leading to cell proliferation and influencing processes critical to cell survival and tumor progression (e.g., angiogenesis, apoptosis, metastasis).2 4

  • Precise mechanism of antineoplastic activity not fully elucidated; further study needed to determine if correlation exists between EGFR receptor expression and response to gefitinib.1

Use in specific populations


Risk Summary

Based on its mechanism of action and animal data, Iressa can cause fetal harm when administered to a pregnant woman. In animal reproductive studies, oral administration of gefitinib from organogenesis through weaning resulted in fetotoxicity and neonatal death at doses below the recommended human dose (see Animal Data). Advise pregnant women of the potential hazard to a fetus or potential risk for loss of the pregnancy.

The background risk of major birth defects and miscarriage for the indicated population is unknown; however, the background risk in the U.S. general population of major birth defects is 2-4% and miscarriage is 15-20% of clinically recognized pregnancies.


Animal Data

A single dose study in rats showed that gefitinib crosses the placenta after an oral dose of 5 mg/kg (30 mg/m2, about 0.2 times the recommended human dose on a mg/m2 basis). When pregnant rats were treated with 5 mg/kg from the beginning of organogenesis to the end of weaningthere was a reduction in the number of offspring born alive. This effect was more severe at 20 mg/kg (approximate the human clinical dose on a mg/m2 basis) and was accompanied by high neonatal mortality soon after parturition. In rabbits, a dose of 20 mg/kg/day (240 mg/m2, about twice the recommended dose in humans on a mg/m2 basis) caused reduced fetal weight.


Risk Summary

It is not known whether Iressa is excreted in human milk. Animal studies indicate the gefitinib and its metabolites are present in rat milk at a concentration higher than those in maternal plasma. Because of the potential for serious adverse reactions in nursing infants from Iressa, advise women to discontinue breast-feeding during treatment with Iressa.


Animal Data

Levels of gefitinib and its metabolites were 11-to-19-fold higher in milk than in blood, after oral exposure of lactating rats to a dose of 5 mg/kg.

Females and Males of Reproductive Potential


Based on its mechanism of action and animal data, Iressa can cause fetal harm when administered to a pregnant woman [see Use in Specific Populations (8.1)]. Advise females of reproductive potential to use effective contraception during treatment with Iressa and for at least two weeks following completion of therapy.


Iressa may result in reduced fertility in females of reproductive potential [see Nonclinical Toxicology (13.1)].

Pediatric Use

The safety and effectiveness of Iressa in pediatric patients have not been established.

Geriatric Use

Of the 823 patients enrolled in two randomized, active-controlled clinical trials 374 patients (45%) were 65 years and older, and 93 patients (11%) were 75 years and older. No overall differences in safety were observed between patients 65 years and older and those younger than 65 years. There is insufficient information to assess for differences in efficacy between older and younger patients.

Renal Impairment

Less than four percent (<4%) of gefitinib and its metabolites are excreted via the kidney. No clinical studies were conducted with Iressa in patients with severe renal impairment.

Hepatic Impairment

The systemic exposure of gefitinib was compared in patients with mild, moderate, or severe hepatic impairment due to cirrhosis (according to Child-Pugh classification) and healthy subjects with normal hepatic function (N=10/group). The mean systemic exposure (AUC0-∞) was increased by 40% in patients with mild impairment, 263% in patients with moderate impairment, and 166% in patients with severe hepatic impairment. Monitor adverse reactions when Iressa is administered to patients with moderate and severe hepatic impairment.

In a study comparing 13 patients with liver metastases and moderate hepatic impairment (addition of CTC grade of baseline AST/SGOT, ALP, and bilirubin equals 3 to 5) to 14 patients with liver metastases and normal hepatic function, the systemic exposure of gefitinib was similar [see Warnings and Precautions (5.2)].

Clinical Studies

Non-Small Cell Lung Cancer (NSCLC)

Study 1

The efficacy and safety of Iressa for the first-line treatment of patients with metastatic NSCLC containing EGFR exon 19 deletions or L858R substitution mutations was demonstrated in a multicenter, single-arm, open-label clinical study (Study 1). A total of 106 treatment-naive patients with metastatic EGFR mutation positive NSCLC received Iressa at a dose of 250 mg once daily until disease progression or intolerable toxicity. The major efficacy outcome measure was objective response rate (ORR) according to RECIST v1.1 as evaluated by both a Blinded Independent Central Review (BICR) and investigators. Duration of response (DOR) was an additional outcome measure. Eligible patients were required to have a deletion in EGFR exon 19 or L858R, L861Q, or G719X substitution mutation and no T790M or S768I mutation or exon 20 insertion in tumor specimens as prospectively determined by a clinical trial assay. Tumor samples from 87 patients were tested retrospectively using the therascreen® EGFR RGQ PCR Kit.

The study population characteristics were: median age 65 years, age 75 years or older (25%), age less than 65 years (49%), white (100%), female (71%), never smokers (64%), WHO PS 0 (45%), WHO PS 1 (48%), WHO PS 2 (7%), and adenocarcinoma histology (97%). Sixty patients had exon 19 deletions (65%), 29 patients had L858R substitution (31%), while two patients each had tumors harboring L861Q or G719X substitution mutation.

The median duration of treatment was 8.0 months. Efficacy results from Study 1 are summarized below.

Table 3 – Efficacy Results in Study 1
* BICR, Blinded Independent Central Review † 17 patients without target lesion at baseline detected by BICR were deemed non responders ‡ Determined by RECIST v 1.1

Efficacy Parameter

BICR* Assessment


Investigator Assessment

Objective Response Rate‡

(95% CI)


(41, 59)


(61, 78)

Complete Response Rate



Partial Response Rate



Median Duration of Response (months)

(95% CI)


(5.6, 11.1)


(7.6, 11.3)

The response rates were similar in patients whose tumors had EGFR exon 19 deletions and exon 21 L858R substitution mutations. Two partial responses were observed in both patients whose tumors had G719X substitution mutation with duration of response of at least 2.8 months and 5.6 months, respectively. One of two patients whose tumors had L861Q substitution mutation also achieved a partial response with duration of response of at least 2.8 months.

Study 2

The results of Study 1 were supported by an exploratory analysis of a subset of a randomized, multicenter, open-label trial (Study 2) conducted in patients with metastatic adenocarcinoma histology NSCLC receiving first-line treatment. Patients were randomized (1:1) to receive Iressa 250 mg orally once daily or up to 6 cycles of carboplatin/paclitaxel. The efficacy outcomes included progression-free survival (PFS) and objective response rate (ORR) as assessed by BICR.

The subset population consisted of 186 of 1217 patients (15%) determined to be EGFR positive by the same clinical trial assay as used in Study 1 and had radiographic scans available for a retrospective assessment by BICR. In this subset, there were 88 Iressa-treated patients and 98 carboplatin/paclitaxel-treated patients.

Demographic and baseline characteristics of this subset were a median age of 59 years, age 75 years or older (7%), age less than 65 (70%), Asian (100%), female (83%), never smokers (96%), adenocarcinoma histology (100%), and PS 0-1 (94%).

The median duration of treatment for Iressa-treated patients was 9.8 months. The hazard ratio for PFS favored the Iressa-treated patients [HR 0.54 (95% CI: 0.38, 0.79)] with a median PFS of 10.9 months for the Iressa-treated patients and 7.4 months for the carboplatin/paclitaxel-treated patients as assessed by BICR. In addition, the objective response rate was 67% (95% CI: 56, 77) for Iressa-treated patients and 41% (95% CI: 31, 51) for carboplatin/paclitaxel-treated patients based on BICR assessment. The median duration of response was 9.6 months for Iressa-treated patients and 5.5 months for carboplatin/paclitaxel-treated patients.

How should I use Iressa?

Iressa should only be administered under the supervision of a qualified healthcare provider experienced in the use of cancer chemotherapeutic agent.

Your doctor will perform blood tests to make sure you have the correct tumor type to be treated with Iressa.

Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use this medicine in larger or smaller amounts or for longer than recommended.

You may take Iressa with or without food.

To make swallowing easier:

  • Place the tablet into a glass of water (4 to 8 ounces) and stir for about 15 minutes.

  • Do not use any liquid other than water.

  • Stir and drink this mixture right away. Do not save for later use.

  • To make sure you get the entire dose, add 4 to 8 more ounces of water to the same glass, swirl gently and drink right away.

  • This mixture may also be given through a nasogastric (NG) tube. Ask your healthcare provider for instructions.

While using Iressa, you may need frequent blood tests to check your liver function.

Store at room temperature away from moisture and heat.

Iressa dosing information

Usual Adult Dose for Non-Small Cell Lung Cancer:

250 mg orally once a day

Duration of therapy: Until disease progression or unacceptable toxicity

-Information on FDA-approved tests for detection of EGFR mutations in NSCLC:

Use: First-line treatment of metastatic non-small cell lung cancer (NSCLC) whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 (L858R) substitution mutations as detected by an FDA-approved test.

Iressa side effects

Get emergency medical help if you have signs of an allergic reaction to Iressa: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Call your doctor at once if you have:

  • severe or ongoing diarrhea;

  • sudden chest pain or discomfort, new or worsening cough with fever, trouble breathing;

  • blurred vision, watery eyes, eye pain or redness, eyes being more sensitive to light;

  • liver problems - nausea, upper stomach pain, itching, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

  • signs of stomach bleeding - severe stomach pain, bloody or tarry stools, coughing up blood or vomit that looks like coffee grounds; or

  • severe skin reaction - fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common Iressa side effects may include:

  • diarrhea;

  • acne;

  • dry skin; or

  • itching or skin rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.