Osimertinib Combined With Chemotherapy in Patients Who Had Distant Recurrence After Adjuvant Osimertinib for EGFRm Resectable SIB-IIIA NSCLC.

Inclusion Criteria for pre-screening:

1. Prior complete surgical resection (R0) and adjuvant osimertinib in EGFRm resectable SIB-IIIA NSCLC (AJCC 7th edition).
2. Off-treatment recurrence (including completed 3 years adjuvant osimertinib \& discontinued adjuvant osimertinib before 3 years due to non-recurrence reason).
3. Newly diagnosed distant recurrent NSCLC (IVA or IVB) (per Version 9 of the International Association for the Study of Lung Cancer \[IASLC\] Staging Manual in Thoracic Oncology).
4. ≥6 months interval between recurrence and completion or discontinuation of adjuvant osimertinib.
5. Histologically/cytologically confirmed nonsquamous NSCLC (Investigators confirmed recurrence of primary lesion allowed if biopsy not available)
6. No prior systemic anti-cancer therapy after adjuvant therapy, but can receive local therapy (including surgery, radiotherapy, etc. per investigator choice).
7. Patients with asymptomatic or stable CNS metastases allowed.

Inclusion Criteria for screening:

1. Male or female, at least 18 years of age. Type of patient and disease characteristics
2. EGFR mutation (Exon 19del/Exon 21 L858R)-reconfirmed for study entry (mandatory undergo NGS by plasma, and tissue if applicable).
3. Life expectancy \>12 weeks at Day 1.

Exclusion Criteria:

1. Patients with only local/regional recurrence.
2. Spinal cord compression and symptomatic brain metastases.
3. Past medical history of ILD/pneumonitis, including radiation pneumonitis (apart from radiation pneumonitis that did not require steroids), or drug-induced ILD/pneumonitis, or has suspected ILD/pneumonitis that cannot be ruled out by imaging at screening.
4. Adjuvant osimertinib therapy was discontinued due to the occurrence of severe adverse events.
5. Prior with other adjuvant EGFR-TKIs (excluding osimertinib).
6. Refractory nausea and vomiting, chronic gastrointestinal diseases, inability to swallow the formulated product or previous significant bowel resection that would preclude adequate absorption of osimertinib.
7. History of hypersensitivity to active or inactive excipients of osimertinib or drugs with a similar chemical structure or class to osimertinib.
8. Contraindication for pemetrexed and cisplatin/carboplatin according to local approved label.