Erlotinib

Absorption

Erlotinib is about 60% absorbed after oral administration and its bioavailability is substantially increased by food to almost 100%. Peak plasma levels occur 4 hours after dosing. The solubility of erlotinib is pH dependent. Solubility decreases pH increases. Smoking also decrease the exposure of erlotinib.

Toxicity

Symptoms of overdose include diarrhea, rash, and liver transaminase elevation. The most common adverse reactions (>50%) in NSCLC are rash, diarrhea, anorexia and fatigue. The most common adverse reactions (>50%) in pancreatic cancer are fatigue, rash, nausea and anorexia.

Description

Erlotinib is a tyrosine kinase inhibitor which acts on the epidermal growth factor receptor (EGFR), inhibiting EGFR-associated kinase activity (IC₅₀ = 2.5 μM). This inhibits tumor growth in human head and neck carcinoma HN5 tumor xenografts in mice with an ED₅₀ value of 9 mg/kg. Erlotinib also suppresses cyclin-dependent kinase 2 (Cdk2) activity in breast cancer cells (IC₅₀ = 4.6 μM) and JAK2 mutant JAK2^V617F positive hematopoietic progenitor cells (IC₅₀ = 5 μM), which is associated with polycythemia vera, idiopathic myelofibrosis, and essential thrombocythemia. Formulations containing erlotinib have been used to treat certain forms of cancer, including non-small cell lung cancer.

The Uses of Erlotinib

Erlotinib HCl is an HER1/EGFR inhibitor with IC50 of 2 nM.

Indications

Erlotinib is indicated for:
The safety and efficacy of erlotinib have not been established for patients with NSCLC whose tumors show other EGFR mutations. Additionally it is not recommended for use in combination with platinum-based chemotherapy.

What are the applications of Application

Erlotinib, Free Base is a tyrosine kinase inhibitor

Background

Erlotinib is an inhibitor of the epidermal growth factor receptor (EGFR) tyrosine kinase that is used in the treatment of non-small cell lung cancer, pancreatic cancer and several other types of cancer. It is typically marketed under the trade name Tarceva. Erlotinib binds to the epidermal growth factor receptor (EGFR) tyrosine kinase in a reversible fashion at the adenosine triphosphate (ATP) binding site of the receptor. Recent studies demonstrate that erlotinib is also a potent inhibitor of JAK2V617F, which is a mutant form of tyrosine kinase JAK2 found in most patients with polycythemia vera (PV) and a substantial proportion of patients with idiopathic myelofibrosis or essential thrombocythemia. This finding introduces the potential use of erlotinib in the treatment of JAK2V617F-positive PV and other myeloproliferative disorders.

Metabolism

Metabolism occurs in the liver. In vitro assays of cytochrome P450 metabolism showed that erlotinib is metabolized primarily by CYP3A4 and to a lesser extent by CYP1A2, and the extrahepatic isoform CYP1A1.