Erlotinib free base;
|Appearance||White to off-white crystalline powder|
|Storage and Handling||Dry, dark and at 0 – 4 C for short term (days to weeks) or -20 C for long term (months to years).|
Erlotinib, sold under the brand name Tarceva among others, is a medication used to treat non-small cell lung cancer (NSCLC) and pancreatic cancer. Specifically it is used for NSCLC with mutations in the epidermal growth factor receptor (EGFR) — either an exon 19 deletion (del19) or exon 21 (L858R) substitution mutation — which has spread to other parts of the body. It is taken by mouth.
Erlotinib is a quinazoline derivative with antineoplastic properties. Competing with adenosine triphosphate, erlotinib reversibly binds to the intracellular catalytic domain of epidermal growth factor receptor (EGFR) tyrosine kinase, thereby reversibly inhibiting EGFR phosphorylation and blocking the signal transduction events and tumorigenic effects associated with EGFR activation.
Erlotinib was approved for medical use in the United States in 2004. It is on the World Health Organization’s List of Essential Medicines, which lists the safest and most effective medicines needed in a health system.
Erlotinib Mechanism of Action
Erlotinib is an epidermal growth factor receptor inhibitor (EGFR inhibitor). The drug follows Iressa (gefitinib), which was the first drug of this type.
Erlotinib specifically targets the epidermal growth factor receptor (EGFR) tyrosine kinase, which is highly expressed and occasionally mutated in various forms of cancer. It binds in a reversible fashion to the adenosine triphosphate (ATP) binding site of the receptor. For the signal to be transmitted, two EGFR molecules need to come together to form a homodimer.
These then use the molecule of ATP to trans-phosphorylate each other on tyrosine residues, which generates phosphotyrosine residues, recruiting the phosphotyrosine-binding proteins to EGFR to assemble protein complexes that transduce signal cascades to the nucleus or activate other cellular biochemical processes. When erlotinib binds to EGFR, formation of phosphotyrosine residues in EGFR is not possible and the signal cascades are not initiated.
Erlotinib also is a tyrosine kinase receptor inhibitor that is used in the therapy of advanced or metastatic pancreatic or non-small cell lung cancer. Erlotinib therapy is associated with transient elevations in serum aminotransferase levels during therapy and rare instances of clinically apparent acute liver injury.
Erlotinib is a reversible first-generation receptor tyrosine kinase inhibitor (along with Gefitinib) acting primarily on the epidermal growth factor receptor (EGFR), a member of the ErbB receptor family. The drug interacts with both wild type and mutation EGFR. The ErbB family can form homodimers or heterodimers, which are often implicated in downstream effects and pathogenesis of many types of carcinomas studied in humans. Receptor tyrosine kinase inhibitors (TKI) prevent the phosphorylation of their substrate in the cell signaling pathway. EGFR normally plays a role in many cellular functions, including differentiation, proliferation, and angiogenesis, all of which are hallmarks of cancer.
EGFR mutation in NSCLC is typically an activating mutation. Some patient characteristics that make the presence of EGFR mutation more likely include no history of smoking confirmed adenocarcinoma by histologic analysis, Asian ethnicity, and female sex. Secondary mutations in the EGFR commonly occur, which this article describes below.
Erlotinib Side Effects & Warning
The following side effects are common for patients taking Erlotinib:
▪ Poor appetite
▪ Shortness of breath
▪ Nausea and vomiting
These side effects are less common side effects of patients receiving Erlotinib:
▪ Mouth sores
▪ Dry skin
▪ Eye irritation
▪ Abdominal pain
Not all side effects are listed above. Some that are rare (occurring in less than 10% of patients) are not listed here. However, you should always inform your health care provider if you experience any unusual symptoms.
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