Inclusion Criteria:
* 1\. Provision of informed consent before any study-specific procedures, sampling and analyses.
2\. Male or female, age at least 18 years. 3. Histologically confirmed diagnosis of primary non-small lung cancer (NSCLC) on predominantly non-squamous histology.
4\. MRI or CT scan of the brain must be done before surgery to exclude brain metastasis.
5\. Complete surgical resection of the primary NSCLC and lymphadenectomy are mandatory. All gross disease must have been removed at the end of surgery. All surgical margins of resection must be negative for tumor.
6\. Patients must be classified post-operatively as Stage IIA, IIB, IIIA or IIIB (only T3N2M0) based on pathologic criteria.
7\. Confirmation by the central laboratory that the tumor harbors one of the 2 common EGFR mutations known to be associated with EGFR-TKI sensitivity (Ex19del, L858R), either alone or in combination with other EGFR mutations including T790M.
8\. Complete recovery from surgery and standard post-operative therapy (if applicable) at the time of randomization.
9\. A WHO performance status of 0-1 with no deterioration over the past 2 weeks and a minimum life expectancy of 12 weeks.
10\. Female patients should be using adequate contraceptive measures and should not be breastfeeding at the screening period, during the study, and six months after the last dosing of study. A pregnancy test should be done before first dosing unless having evidence of non-child-bearing potential.
11\. Male patients should be willing to use barrier contraception (condoms).
Exclusion Criteria:
* 1\. Patients who have had only segmentectomies or wedge resections. 2. Treatment with any of the following:
1. Any prior anticancer therapy for the current lung cancer (pre-operative (neoadjuvant) platinum-based or other chemotherapy, pre-operative or post-operative or planned radiation therapy, neoadjuvant or adjuvant EGFR-TKI, other targeted therapy and immunotherapy).
2. Major surgery (including primary tumor surgery, excluding placement of vascular access) within 3 weeks of the first dose of study drug.
3. Patients currently receiving medications or herbal supplements known to be strong inducers and inhibitors of cytochrome P450 (CYP) 3A4.
4. Treatment with an investigational drug within five half-lives of the compound or any of its related material.
3\. Inadequate bone marrow reserve or organ function. 4. Any of the following cardiac criteria:
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1. Mean resting corrected QT interval (QTc) \> 470 ms obtained from 3 electrocardiograms (ECGs), using the screening clinic's ECG machine and Fridericia's formula for QT interval correction (QTcF).
2. Any clinically important abnormalities in rhythm, conduction, or morphology of the resting ECG (e.g., PR interval \> 250 ms).
3. Any factors that increase the risk of QTc prolongation or risk of arrhythmic events, such as heart failure or any concomitant medication known to prolong the QT interval.
4. Left ventricular ejection fraction (LVEF) ≤ 40%. 5. History of other malignancies, excluding full treated non-melanoma skin cancer, in-situ cancer, or other solid tumors that hadn't recurrent for \> 5 years following the end of treatment.
6\. Any evidence of severe or uncontrolled systemic diseases (including uncontrolled hypertension and active bleeding diatheses) or active infection (including hepatitis B, hepatitis C, and human immunodeficiency virus (HIV)).
7\. Refractory nausea, vomiting, or chronic gastrointestinal diseases, or inability to swallow the study drug that would preclude adequate absorption of Almonertinib.
8\. History of interstitial lung disease (ILD), drug-induced ILD, radiation pneumonitis which required steroid treatment, or any evidence of clinically active ILD.
9\. Any unresolved toxicities from prior therapy greater than CTCAE Grade 1 except alopecia and Grade 2 prior platinum-therapy related neuropathy.
10\. History of hypersensitivity to any active or inactive ingredient of Almonertinib or to drugs with a similar chemical structure or class to Almonertinib.
11\. Judgment by the investigator that the patient should not participate in the study if the patient is unlikely to comply study procedures, restrictions, and requirements.
12\. Any severe and uncontrolled ocular disease that may, in the ophthalmologist's opinion, present a specific risk to the patient's safety.
13\. Any disease or condition that, in the opinion of the investigator, would compromise the safety of the patient or interfere with study assessments.
