Osimertinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that binds to certain mutant forms of EGFR (T790M, L858R, and exon 19 deletion) that predominate in non-small cell lung cancer (NSCLC) tumours following treatment with first-line EGFR-TKIs. As a third-generation tyrosine kinase inhibitor, osimertinib is specific for the gate-keeper T790M mutation which increases ATP binding activity to EGFR and results in poor prognosis for late-stage disease. Furthermore, osimertinib has been shown to spare wild-type EGFR during therapy, thereby reducing non-specific binding and limiting toxicity.

Osimertinib is indicated for the treatment of patients with metastatic epidermal growth factor receptor (EGFR) T790M mutation-positive non-small cell lung cancer (NSCLC), as detected by an FDA-approved test, whose disease has progressed on or after EGFR tyrosine kinase inhibitor (TKI) therapy.

The recommended dose of Osimertinib is 80 mg once a day until disease progression or unacceptable toxicity. Osimertinib can be taken with or without food. If a dose of Osimertinib is missed, do not make up the missed dose and take the next dose as scheduled.

Administration

Administration To Patients Who Have Difficulty Swallowing Solids: Disperse tablet in 60 ml (2 ounces) of non-carbonated water only. Stir until tablet is dispersed into small pieces (the tablet will not completely dissolve) and swallow immediately. Do not crush, heat, or ultrasonicate during preparation. Rinse the container with 120 ml to 240 ml (4 to 8 ounces of) water and immediately drink.

If administration via nasogastric tube is required, disperse the tablet as above in 15 ml of non-carbonated water, and then use an additional 15 ml of water to transfer any residues to the syringe. The resulting 30 ml liquid should be administered as per the nasogastric tube instructions with appropriate water flushes (approximately 30 ml).

Common side effects are Interstitial Lung Disease or Pneumonitis, QTc Interval Prolongation, Cardiomyopathy, Keratitis

Use in Pregnancy: There are no or limited amount of data from the use of Osimertinib in pregnant women. Studies in animals have shown reproductive toxicity. Based on its mechanism of action and preclinical data, Osimertinib may cause foetal harm when administered to a pregnant woman. Administration of osimertinib to pregnant rats was associated with embryolethality, reduced foetal growth and neonatal death at exposures similar to what is expected in humans. Osimertinib is not recommended during pregnancy and in women of childbearing potential not using contraception.

Use in Lactation: It is not known whether osimertinib or its metabolites are excreted in human milk. Administration to rats during gestation and early lactation was associated with adverse effects, including reduced growth rates and neonatal death. There is insufficient information on the excretion of osimertinib or its metabolites in animal milk. A risk to the suckling child cannot be excluded. Breast-feeding should discontinue during treatment with Osimertinib.

Fertility: There are no data on the effect of Osimertinib on human fertility. Results from animal studies have shown that Osimertinib has effects on male and female reproductive organs and could impair fertility