Osimertinib – EGFR Tyrosine Kinase Inhibitor

Osimertinib is an innovative targeted anti-cancer medication and a third-generation irreversible tyrosine kinase inhibitor (TKI) of the Epidermal Growth Factor Receptor (EGFR). It was specifically developed to combat the most challenging forms of lung cancer that have developed resistance to previous generations of drug therapy.

The mechanism of action involves the selective and irreversible binding to mutant forms of the EGFR receptor. Unlike earlier inhibitors, osimertinib effectively suppresses not only classical sensitizing mutations (L858R and exon 19 deletion) but also the specific T790M resistance mutation. This mutation often emerges during treatment and blocks the effects of other drugs. Osimertinib halts the signaling pathways that stimulate tumor cell division and survival while exhibiting significantly lower activity against normal (wild-type) EGFR, thereby reducing toxicity to healthy tissues. A major advantage is the drug's high ability to cross the blood-brain barrier, allowing it to act effectively on brain metastases.

The medication is taken orally once daily, providing continuous suppression of tumor cell activity.

Wikipedia page

Indications

Osimertinib is indicated as monotherapy for the treatment of adult patients in the following clinical scenarios:

Adjuvant Therapy: following complete tumor resection in patients with non-small cell lung cancer (NSCLC) whose tumors harbor EGFR mutations.
First-line Therapy: treatment of locally advanced or metastatic NSCLC with EGFR mutations (exon 19 deletion or L858R mutation).
Resistant Cancer: treatment of locally advanced or metastatic NSCLC in patients with the T790M mutation whose disease has progressed on or after therapy with other EGFR tyrosine kinase inhibitors.

Dosage and administration

The osimertinib dosing regimen requires regularity and the monitoring of certain physiological parameters.

Standard Dose: 80 mg (one tablet) taken once daily.
Administration: the tablet should be swallowed whole, with or without food, at the same time each day. For patients with swallowing difficulties, the tablet can be dispersed in 50 mL of non-carbonated water (no other liquids should be used).
Missed Dose: if a dose is missed, it should be taken only if the next scheduled dose is more than 12 hours away.
Duration: in the adjuvant setting (after surgery), treatment can continue for up to 3 years; for metastatic disease, it is continued until disease progression.
Dose Adjustment: in cases of severe adverse reactions, the dose may be reduced to 40 mg once daily or temporarily interrupted.

The use of osimertinib is restricted in the following cases:

Hypersensitivity: known allergy to osimertinib or any of its excipients.
St. John's Wort: concomitant use with products containing St. John’s wort is prohibited, as it significantly reduces the efficacy of the treatment.
Pregnancy and Lactation: the drug is fetotoxic; breastfeeding during therapy and for 2 weeks after the final dose is prohibited.
Pediatric Use: safety and efficacy in children and adolescents under 18 years of age have not been established.

Osimertinib therapy may cause a range of adverse events, most of which are manageable:

Dermatologic: dry skin, pruritus (itching), rash, and inflammation around the nails (paronychia).
Gastrointestinal: diarrhea (most common), stomatitis, nausea, and decreased appetite.
Hematologic: decreased levels of white blood cells, lymphocytes, neutrophils, and platelets.
Cardiovascular: risk of QT interval prolongation and decreased left ventricular ejection fraction (requires ECG and echocardiogram monitoring).
Respiratory: risk of interstitial lung disease (ILD) or pneumonitis (a serious complication requiring immediate discontinuation of the drug).

Frequently Asked Questions

Osimertinib is a third-generation EGFR inhibitor used to treat non-small cell lung cancer with EGFR T790M mutations, as well as first-line therapy for patients with del19 or L858R mutations.

Osimertinib is available on the Unifarm website as generics from Indian manufacturers. Delivery across Ukraine. To place an order, contact us through the website form or by phone.

Tagrisso is the original drug manufactured by AstraZeneca. Generics contain the same active ingredient at the same dosage but are produced by Indian pharmaceutical companies at significantly lower cost.

The price depends on the manufacturer and dosage. Unifarm offers generics at significantly lower prices compared to the original Tagrisso. Current prices are listed on the product page.

The standard dose is 80 mg once daily regardless of food intake. In certain indications, the dose may be increased to 160 mg. The dosing regimen is determined by the treating oncologist.

The most common side effects include diarrhea, rash, dry skin, paronychia, and stomatitis. Serious adverse reactions include interstitial lung disease and QTc interval prolongation.

Osimertinib is a prescription-only medication. A consultation with an oncologist and a corresponding prescription are required for purchase.