Product Information
Registration Status: ActiveIRESSA TABLET 250mg is approved to be sold in Singapore with effective from 2003-05-22. It is marketed by ASTRAZENECA SINGAPORE PTE LTD, with the registration number of SIN12300P.
This product contains Gefitinib 250mg in the form of TABLET, FILM-COATED. It is approved for ORAL use.
This product is manufactured by ASTRAZENECA UK LTD in UNITED KINGDOM, andKagamiishi Plant in JAPAN.
It is a Prescription Only Medicine that can only be obtained from a doctor or a dentist, or a pharmacist with a prescription from a Singapore-registered doctor or dentist.
Description
Gefitinib (originally coded ZD1839) is a drug used in the treatment of certain types of cancer. Acting in a similar manner to erlotinib (marketed as Tarceva), gefitinib selectively targets the mutant proteins in malignant cells. It is marketed by AstraZeneca under the trade name Iressa.
Indication
For the continued treatment of patients with locally advanced or metastatic non-small cell lung cancer after failure of either platinum-based or docetaxel chemotherapies.
Mechanism of Action
Gefitinib inhibits the epidermal growth factor receptor (EGFR) tyrosine kinase by binding to the adenosine triphosphate (ATP)-binding site of the enzyme. Thus the function of the EGFR tyrosine kinase in activating the Ras signal transduction cascade is inhibited; and malignant cells are inhibited. Gefitinib is the first selective inhibitor of the EGFR tyrosine kinase which is also referred to as Her1 or ErbB-1. EGFR is overexpressed in the cells of certain types of human carcinomas - for example in lung and breast cancers. Overexpression leads to inappropriate activation of the apoptotic Ras signal transduction cascade, eventually leading to uncontrolled cell proliferation.
Pharmacokinetics
- Absorption
- Absorbed slowly after oral administration with a mean bioavailability of 60%. Peak plasma levels occurs 3-7 hours post-administration. Food does not affect the bioavailability of gefitinib.
- Distribution
- * 1400 L [IV administration]
- Metabolism
- Primarily hepatic via CYP3A4. Three sites of biotransformation have been identified: metabolism of the N-propoxymorpholino-group, demethylation of the methoxy-substituent on the quinazoline, and oxidative defluorination of the halogenated phenyl group.
- Elimination
Clearance
* 595 mL/min [IV administration]
Toxicity
The acute toxicity of gefitinib up to 500 mg in clinical studies has been low. In non-clinical studies, a single dose of 12,000 mg/m2 (about 80 times the recommended clinical dose on a mg/m2 basis) was lethal to rats. Half this dose caused no mortality in mice. Symptoms of overdose include diarrhea and skin rash.
Active Ingredient/Synonyms
4-(3'-chloro-4'-Fluoroanilino)-7-methoxy-6-(3-morpholinopropoxy)quinazoline | Gefitinib | N-(3-chloro-4-Fluorophenyl)-7-methoxy-6-(3-(4-morpholinyl)propoxy)-4-quinazolinamine | ZD 1839 | Gefitinib |
Source of information: Drugbank (External Link). Last updated on: 3rd July 18. *Trade Name used in the content below may not be the same as the HSA-registered product.