Mechanism Of Action:

Osimertinib is an EGFR tyrosine kinase inhibitor that binds to certain mutant forms of EGFR (T790M, L858R, and exon 19 deletion) that predominate in non-small cell lung cancer tumors 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, it has shown to spare wild-type EGFR during therapy, which leads to reduction of non-specific binding and limiting of toxicity.

Indication:

• It is indicated as adjuvant therapy after tumor resection in adult patients with NSCLC whose tumors have EGFR exon 19 deletions or exon 21 L858R mutations.
• It is indicated for the first-line treatment of adult patients with metastatic  NSCLC whose tumors have EGFR exon 19 deletions or exon 21 L858R mutations.
• It is indicated for the treatment of adult patients with metastatic EGFR T790M mutation-positive NSCLC, as detected by an FDA-approved test, whose disease has progressed on or after EGFR tyrosine kinase inhibitor therapy.