Adagrasib is an oral inhibitor targeting KRASG12C mutations, suitable for second-line treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC). The following is an explanation from four aspects: mechanism of action, clinical guidelines, medication regimen, and monitoring points.

1. Mechanism of action

(1) Selective inhibition of KRASG12C mutant protein, locking its inactive state through covalent binding, and blocking downstream signaling pathways.

(2) Specifically targeting GDP bound KRASG12C, overcoming obstacles in the development of traditional RAS targeted drugs and achieving precise treatment.

2 Clinical Indications

(1) Accelerated FDA approval for adult patients with KRASG12C mutation positive NSCLC requires confirmation of mutation status through genetic testing.

(2) Suitable for second-line treatment after platinum based chemotherapy or immune checkpoint inhibitor therapy failure, with an objective response rate of approximately 43%.

3 Standard Medication Plans

(1) Recommended dosage: 600mg orally twice a day (with a 12 hour interval), taken on an empty stomach or with meals.

(2) The course of treatment continues until disease progression or intolerable toxicity occurs, and the entire tablet should be swallowed to avoid damaging the drug release system.

4 Principles of Dose Adjustment

(1) The first dose should be reduced to 400mg twice daily, and the second dose should be reduced to 200mg twice daily, with a minimum of 200mg/day.

(2) If QTc>500ms, grade 3 hepatotoxicity or interstitial lung disease occurs, the medication should be permanently discontinued, and other grade 3 toxicity should be temporarily suspended until ≤ grade 1 before reducing dosage.

5 Key points for efficacy monitoring

(1) Evaluate tumor response through imaging every 6 weeks and dynamically monitor changes in mutation burden using ctDNA.

(2) After drug resistance, it is recommended to undergo a second biopsy to identify acquired mutations (such as Y96D), and the combination of SHP2 or MEK inhibitors may be considered.

6. Security Management

(1) Before treatment, it is necessary to check liver function, electrocardiogram, electrolytes, and those with baseline QTc>450ms should not be used.

(2) Monitor heart function monthly during treatment and avoid using QT prolonging drugs such as fluoroquinolones in combination.