Background: Aumolertinib is a novel third-generation (3G) epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI). Safety and efficacy of aumolertinib have been demonstrated in patients with EGFR-mutated locally advanced or metastatic (LA/m) NSCLC. (Lu, 2021; Lu, 2022) A phase 3 study in these patients in the first-line setting showed a significant improvement in progression-free survival (PFS) for aumolertinib vs gefitinib (median 19.3 months versus 9.9 months; P < 0.0001). Aumolertinib was generally well-tolerated. (Lu, 2022) Aumolertinib is approved in China for patients with LA/m NSCLC who have an EGFR T790M resistance mutation upon disease progression and for treatment naïve patients with EGFR-mutated NSCLC. Studies evaluating first-generation EGFR-TKI + chemotherapy (chemo) showed improved PFS in select patient populations. (Hosomi, 2019) It is unclear if the addition of chemo to a 3G EGFR-TKI will improve PFS in patients with EGFR-mutated LA/m NSCLC. As the addition of chemo to a 3G EGFR-TKI may prove warranted, there is a need to understand the relative efficacy and safety in the diversity of patients encountered in routine clinical practice. (Tanaka, 2021). Methods: This is a randomized, multi-regional, phase 3 clinical trial comparing aumolertinib + chemo or aumolertinib monotherapy with osimertinib monotherapy. Patients are eligible if they have stage IIIB, IVA, or IVB NSCLC; harbor ex19del or L858R EGFR mutations alone or with other EGFR mutations; and have an ECOG PS of ≤2. Patients are ineligible if they received prior systemic therapy for mNSCLC or are a candidate for curative intent therapy. Eligible patients will be randomized 2:2:1 and stratified by mutation status (ex19del or L858R), ECOG PS (0 vs 1/2), and race (White vs Asian vs other races combined). Anticipated enrollment is 500 patients; 200 to receive aumolertinib + chemo (110 mg PO QD aumolertinib + investigator's choice chemo), 200 to receive osimertinib (80 mg PO QD), and 100 to receive aumolertinib (110 mg PO QD). The primary endpoint is PFS, by blinded independent review committee (BICR) per RECIST 1.1, for aumolertinib + chemo vs osimertinib. Overall survival (OS) is a key secondary endpoint for aumolertinib + chemo vs osimertinib. Additional efficacy endpoints will be assessed for aumolertinib + chemo vs osimertinib and aumolertinib vs osimertinib, as well as safety and patient reported outcomes. Exploratory endpoints include characterizing mechanisms of acquired resistance across all arms, CNS efficacy, and exposure-response relationship. Enrollment began in July 2022. The study is currently recruiting and will include approximately 200 sites globally. The study design will provide a power of 80% at a 2-sided Type I error of 0.05 for the primary endpoint. If the primary endpoint is statistically significant, a sequential test method will be used to evaluate OS. Clinical trial information: NCT05493501.