Gefinix is indicated for the first-line treatment of patients with metastatic non-small cell lung cancer (NSCLC) whose tumors have epidermal growth factor receptor (EGFR) exon 19 deletions or exon 21 (L858R) substitution mutations as detected by an FDA-approved test.
Gefitinib reversibly inhibits the kinase activity of wild-type and certain activating mutations of EGFR, preventing autophosphorylation of tyrosine residues associated with the receptor, thereby inhibiting further downstream signalling and blocking EGFR-dependent proliferation. Gefitinib binding affinity for EGFR exon 19 deletion or exon 21 point mutation L858R mutations is higher than its affinity for the wild-type EGFR. It also inhibits IGF and PDGF-mediated signalling at clinically relevant concentrations; inhibition of other tyrosine kinase receptors has not been fully characterized.
Recommended dose : 250 mg Gefitinib orally once daily with or without food until disease progression or unacceptable toxicity. One should not take a missed dose within 12 hours of the next dose. Administration to Patients who have Difficulty Swallowing Solids : Gefitinib tablets should be immersed in 4 to 8 ounces of water by dropping the tablet in water, and stirred for approximately 15 minutes. The liquid should be immediately drunk or administered through a naso-gastric tube. The container should be rinsed with 4 to 8 ounces of water and immediately drunk or administered through the naso- gastric tube.
Always consult a registered doctor before taking any medicine. This information is for general knowledge only.
The most common side effects of this tablet are- Interstitial Lung Disease, Hepatotoxicity, Gastrointestinal Perforation, Severe or Persistent Diarrhea, Ocular Disorders including Keratitis, Bullous and Exfoliative Skin Disorders.
It is contraindicated in patients with known hypersensitivity to Gefitinib or any other components of this drug.
CYP3A4 Inducer : Drugs that are strong inducers of CYP3A4 increase the metabolism of Gefinix and decrease Gefinix plasma concentrations. Gefinix should be increased to 500 mg daily in patients receiving a strong CYP3A4 inducer (e.g., rifampicin, phenytoin, or tricyclic antidepressant) and should be resumed at 250 mg 7 days after discontinuation of the strong inducer. CYP3A4 Inhibitor : Drugs that are strong inhibitors of CYP3A4 (e.g., ketoconazole and itraconazole) decrease Gefinix metabolism and increase Gefinix plasma concentrations.
Intestinal lung disease (ILD) : ILD or ILD-like adverse drug reactions (e.g., lung infiltration, pneumonitis, acute respiratory distress syndrome, or pulmonary fibrosis) occurred in 1.3% of the 2462 patients who received Gefinix across clinical trials. Gefinix should be withheld and promptly investigated for ILD in any patient who presents with worsening of respiratory symptoms such as dyspnea, cough and fever. It should be permanently discontinued if ILD is confirmed. Hepatotoxicity : Patients receiving Gefinix across clinical trials, 11.4% of patients had increased alanine aminotransferase (ALT), 7.9% of patients had increased aspartate aminotransferase (AST), and 2.7% of patients had increased bilirubin. Periodic liver function testing should be obtained. Gefinix should be withheld in patients with worsening liver function and discontinued in patients with severe hepatic impairment. Gastrointestinal Perforation : Gastrointestinal perforation occurred in three (0.1%) of the 2462 Gefinix-treated patients across clinical trials. It should be permanently discontinued in patients who develop gastrointestinal perforation. Severe or Persistent Diarrhea : Grade 3 or 4 diarrhea occurred in 3% of 2462 Gefinix-treated patients across clinical trials. It should be withheld for severe or persistent (up to 14 days) diarrhea. Ocular Disorders including Keratitis : Ocular disorders keratitis (0.1%), corneal erosion and aberrant eyelash growth (0.2%), conjunctivitis, blephritis and dry eye (6.7%)] occurred in the 2462 Gefinix-treated patients across clinical trials. It should be interrupted or discontinued for severe, or worsening ocular disorders. Bullous and Exfoliative Skin Disorders : Bullous conditions including toxic epidermal necrolysis, Stevens Johnson syndrome and erythema multiforme have been reported from treatment with Gefinix. Erythema multiforme and dermatitis bullous have been reported in two patients (0.08%) across NSCLC trials. Gefinix treatment should be interrupted or discontinued if the patient develops severe bullous, blistering or exfoliating conditions.