What important information is included in the package insert for Dacomitinib? What are the key things to pay attention to when using it?

Dacomitinib, also known as dacomitinib, is an irreversible epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), mainly used to treat EGFR mutation-positive non-small cell lung cancer (NSCLC). Its unique mechanism of action allows it to show good efficacy in partially drug-resistant patients, but it also comes with a certain risk of side effects. Therefore, patients must read the instructions for this drug in detail before using it and follow the doctor's instructions for treatment.
1. Important information in the drug package insert
The instructions for dacomitinib contain many key contents, including indications, usage and dosage, adverse reactions, contraindications, etc. The following is a detailed analysis:
(1) Indications
Dacomitinib is suitable for patients with advanced or metastatic non-small cell lung cancer (NSCLC) with EGFR gene exon 19 deletion (Del19) or exon 21 (L858R) mutation, and is usually used as a first-line treatment option. The drug blocks the growth and spread of cancer cells by irreversibly inhibiting the signaling pathways of EGFR and its family members (HER2 and HER4).
(2) Recommended dosage and usage
Recommended dose: 45 mg orally once daily until disease progression or intolerable toxicity occurs.
Medication time: It can be taken on an empty stomach or with food, but it needs to be taken at a fixed time every day to maintain stable blood concentration.
Dose adjustment: If the patient experiences serious adverse reactions, the dose can be gradually reduced to 30 mg or 15 mg. If the side effects are still intolerable, your doctor may recommend stopping the medication.
(3) Common adverse reactions
Adverse reactions of dacomitinib are common, especially skin and gastrointestinal related symptoms. The following are the main side effects:
Skin reactions: rash, acneiform dermatitis, itching, dryness, photosensitivity, etc., which may affect the patient's quality of life.
Gastrointestinal discomfort: diarrhea, stomatitis, nausea, loss of appetite, etc. Some patients may have severe diarrhea and need to replenish water and electrolytes in time.
Nail damage: Some patients develop paronychia or brittle nails, which can lead to pain or infection.
Abnormal liver function: Dacomitinib may cause liver damage, so liver enzyme levels need to be monitored regularly during treatment.

Interstitial lung disease (ILD): Although rare, if dyspnea, dry cough, or pneumonia-like symptoms occur, you should stop taking the drug and seek medical attention immediately.

2. Key things to note when using
(1) The importance of genetic testing
Dacomitinib is only effective in patients with EGFR mutation-positive lung cancer, so EGFR gene testing must be performed before use. If the patient does not carry an EGFR mutation, blind use may not bring any efficacy and may even increase the risk of drug side effects.
(2) How to manage adverse reactions?
Since dacomitinib has many side effects, patients should understand how to manage these side effects in advance to ensure smooth progress of treatment.
Managing skin reactions: Use a mild moisturizer, avoid prolonged sun exposure, and use your doctor's recommended topical medications (such as steroid or antibiotic ointments) if necessary.
Diarrhea management: Mild diarrhea can be improved by dietary adjustments (such as reducing greasy and spicy foods). In severe cases, antidiarrheal drugs should be used in time and water should be added.
Stomatitis management: Avoid spicy and acidic foods and use a mild mouthwash to maintain oral hygiene.
(3)Drug interactions
Dacomitinib may interact with certain drugs, affecting their efficacy or increasing the risk of side effects, such as:
CYP2D6 inhibitors (such as paroxetine, fluoxetine) may affect the metabolism of dacomitinib, increase the plasma concentration, and increase the risk of toxicity.
Proton pump inhibitors (such as omeprazole) may affect drug absorption and reduce efficacy. If patients need to take antacids, they should consult their doctor to adjust the medication time.
(4) Medication precautions for special groups
Pregnant and lactating women: Dacomitinib may cause harm to the fetus. Pregnant women are prohibited from using it, and effective contraceptive measures must be taken during the medication and for at least 17 days after stopping.
Patients with Impaired Hepatic and Renal Function: Since this drug is primarily metabolized by the liver, dosage adjustments may be required in patients with hepatic impairment. People with renal insufficiency also need to be evaluated before use.
Elderly patients: Elderly patients are more likely to experience serious side effects, such as skin toxicity and diarrhea, and require close monitoring.
3. Monitoring and follow-up during medication
In order to ensure the efficacy of dacomitinib and detect potential adverse reactions in a timely manner, patients need to undergo the following examinations regularly during treatment:
Liver function monitoring (ALT, AST, bilirubin) to prevent drug-induced liver injury;
Routine blood examination, pay attention to the status of white blood cells and platelets;
Pulmonary imaging examination to rule out the possibility of interstitial lung disease;
Skin examination to evaluate rashes and nail damage.
Dacomitinib is an irreversible EGFR-TKI inhibitor that has shown good efficacy in the treatment of EGFR mutation-positive non-small cell lung cancer. However, its side effects are more obvious, especially damage to the skin, gastrointestinal tract and liver function. Patients must strictly follow the doctor's guidance when using it. EGFR gene testing must be performed before taking medicine, and physical condition should be monitored regularly during treatment to reduce risks and improve treatment success rate. In addition, patients should reasonably manage adverse reactions, such as avoiding sun exposure, paying attention to oral care, and handling diarrhea in a timely manner to ensure the smooth progress of treatment.
Reference: https://www.pfizer.com/products/product-detail/vizimpro