Osikin 80 mg contains Osimertinib, a third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) used in the treatment of non-small cell lung cancer (NSCLC). It is a targeted anticancer therapy designed to selectively inhibit both EGFR-sensitizing mutations and the T790M resistance mutation, while sparing normal EGFR to a greater extent than earlier EGFR inhibitors.

Indications

Osikin 80 mg is indicated for the treatment of adult patients with EGFR mutation-positive NSCLC, including:

• First-line treatment of patients with metastatic NSCLC whose tumors have EGFR exon 19 deletions or exon 21 (L858R) substitution mutations.

• Treatment of patients with metastatic EGFR T790M-positive NSCLC whose disease has progressed on or after prior EGFR-TKI therapy.

Confirmation of EGFR mutation status using a validated diagnostic test is required prior to initiating therapy.

Mechanism of Action

Osimertinib is an irreversible EGFR-TKI that selectively inhibits mutant forms of EGFR, including T790M, exon 19 deletion, and L858R mutations. It binds covalently to the EGFR tyrosine kinase domain, blocking downstream signaling pathways responsible for tumor cell proliferation and survival. This targeted action results in reduced tumor growth and increased cancer cell apoptosis, while minimizing effects on normal cells.

Pharmacology

• Absorption: Osimertinib is well absorbed following oral administration, with peak plasma concentrations achieved within 6 hours. Food has no clinically significant effect on absorption.

• Distribution: Highly protein bound and widely distributed in tissues, including lung tissue and the central nervous system.

• Metabolism: Primarily metabolized by CYP3A4 and CYP3A5 to active metabolites.

• Elimination: Excreted mainly via feces, with a smaller proportion eliminated in urine. The effective half-life supports once-daily dosing.

Dosage and Administration

• Recommended Dose: 80 mg taken once daily, with or without food.

• Tablets should be swallowed whole with water. If patients have difficulty swallowing, the tablet may be dispersed in water according to medical guidance.

• Treatment should be continued until disease progression or unacceptable toxicity.

• Dose modification or interruption may be required in patients experiencing severe adverse reactions.

Adverse Effects

Common side effects include diarrhea, rash, dry skin, nail toxicity, fatigue, and decreased appetite. Most adverse reactions are mild to moderate in severity.
Serious but less common adverse effects include:

• Interstitial lung disease (ILD)/pneumonitis

• QT interval prolongation

• Cardiomyopathy

• Keratitis and other ocular disorders

Regular monitoring is recommended to detect these conditions early.

Contraindications and Precautions

• Hypersensitivity to Osimertinib or any component of the formulation.

• Caution is advised in patients with pre-existing lung disease, cardiac disorders, or electrolyte imbalances.

• Avoid concomitant use with strong CYP3A inducers, as they may reduce drug efficacy.

Pregnancy and Lactation

Osikin 80 mg may cause fetal harm when administered during pregnancy. Effective contraception is recommended during treatment and for a specified period after discontinuation. Breastfeeding should be avoided during therapy.

Therapeutic Class

Antineoplastic Agent / EGFR Tyrosine Kinase Inhibitor

Storage

Store below 30°C, protected from light and moisture, and keep out of reach of children.