Study to Evaluate Efficacy and Safety of Firmonertinib Compared With Investigator's Choice of EGFR Inhibitor as First-Line Treatment in Participants Who Have Locally Advanced or Metastatic NSCLC With EGFR P-Loop and Alpha C-Helix Compressing (PACC) Uncommon Mutations

Key Eligibility Criteria: * Histologically or cytologically documented, locally advanced or metastatic Non-Small Cell Lung Cancer (NSCLC) not amenable to curative surgery or radiotherapy. * Documented results of the presence of an Epidermal Growth Factor Receptor (EGFR) PACC mutation in tumor tissue or blood from local testing. * No prior systemic anticancer therapy regimens received for locally advanced or metastatic Non-Small Cell Lung Cancer (NSCLC) including prior treatment with any Epidermal Growth Factor Receptor (EGFR)-targeting agents (e.g., previous (EGFR) TKIs, monoclonal antibodies, or bispecific antibodies). * Patients who have received prior neo-adjuvant and/or adjuvant chemotherapy, immunotherapy, or chemo radiotherapy for non-metastatic disease must have experienced a treatment free interval of at least 12 months. * Patients with asymptomatic CNS metastases are eligible. * List of eligible PACC mutations: E709X, E709A, E709H, E709V, E709K E709\_T710delinsD, E709\_T710delinsA, E709\_T710delinsG, L718M, L718P, L718Q, L718V, G719X, G719A, G719C, G719D, G719S, G724S, E736K, I740\_K745dup, I740\_K745dupIPVAIK, I744\_K745insKIPVAI, L747P, L747S, K757M, K757R, V765L, S768I, S768\_V769delinsIL, S768\_V769delinsIM, S768\_V769delinsPL, V769L, V769M, N771G, H773\_V774delinsLM, V774M, R776C, R776H, G779F, L792H, G796S, T854A, T854S, T854I, A647T, R675W, S768C, A755D, A750\_I759delinsPN, T751\_I759delinsN