• Age ≥ 18 years

• Biopsy proven metastatic non-small cell lung cancer, confirmed at enrolling institution

• Somatic activating mutation in EGFR in pre-treatment tumor biopsy/ cytology from pleural fluid or cfDNA

• Either have not started a prior EGFR TKI therapy or may have started osimertinib within 3 weeks of confirming eligibility and enrollment criteria of measurable disease per approval of PI, with no prior chemotherapy for treatment of metastatic disease (adjuvant therapy \> 6 months prior to study start is acceptable)

• Measurable (RECIST 1.1) indicator lesion not previously irradiated with measurable disease determined per treating investigator. If a patient has already started on osimertinib there must be available pre-osimertinib baseline tumor assessments, to be utilized for RECIST 1.1 assessment.

• Karnofsky performance status (KPS)≥70%,

• Ability to swallow oral medications

• Adequate organ function (use of G-CSF and/or transfusion to meet these criteria are not allowed)

‣ Hemoglobin ≥ 9 g/dL

⁃ Platelets ≥ 150,000mm\^3 or 150 x 10\^9/L

⁃ AST, ALT ≤ 2.5 x ULN with no liver metastases or \< 5x ULN with the presence of liver metastases

⁃ Total bilirubin ≤ 1.5 x ULN if no liver metastases or \< 3 x ULN in the presence of documented Gilbert's Syndrome (unconjugated hyperbilirubinemia) or liver metastases

⁃ Absolute neutrophil count (ANC) ≥ 1500 cells/mm\^3

⁃ Creatinine ≤ ULN OR calculated creatinine clearance ≥ 60ml/min calculated by Cockcroft and Gault equation

⁃ Creatinine clearance ≥ 60 mL/min calculated by Cockcroft and Gault equation

• Willing to use highly effective contraceptive measures if of child-bearing potential or if the patient's sexual partner is a woman of child-bearing potential:

‣ Female subjects should be using highly effective contraceptive measures, and must have a negative pregnancy test and not be breast-feeding prior to start of dosing through 6 weeks after discontinuing the study drug if of child-bearing potential or must have evidence of non-child-bearing potential by fulfilling one of the following criteria at screening:

⁃ Post-menopausal defined as aged more than 50 years and amenorrheic for at least 12 months following cessation of all exogenous hormonal treatments

⁃ Women under 50 years old would be consider postmenopausal if they have been amenorrheic for 12 months or more following cessation of exogenous hormonal treatments and with LH and FSH levels in the post-menopausal range for the institution

⁃ Documentation of irreversible surgical sterilization by hysterectomy, bilateral oophorectomy or bilateral salpingectomy but not tubal ligation

⁃ Male subjects should be willing to use barrier contraception and avoid sperm donation prior to the start of dosing through 4 months of discontinuing the study drug

• Patients with detectable plasma EGFR mutations at C2D1

• Karnofsky performance status (KPS) ≥ 70%

• Adequate organ function

‣ Hemoglobin ≥ 9 g/dL

⁃ Platelets ≥ 100,000mm\^3 or 100 x 10\^9/L

⁃ Creatinine ≤ ULN OR calculated creatinine clearance ≥ 60ml/min

⁃ AST, ALT ≤ 3x ULN with no liver metastases or ≤ 5x ULN with the presence of liver metastases

⁃ Total bilirubin ≤ 1.5 x ULN if no liver metastases or ≤ 3 x ULN in the presence of documented Gilbert's Syndrome (unconjugated hyperbilirubinemia) or liver metastases

⁃ Absolute neutrophil count (ANC) ≥ 1500 cells/mm3Must have at least stable disease per RECIST 1.1 assessment prior to initiating chemotherapy at C4D1

⁃ Eligibility testing (KPS, bloodwork) should be tested at C3D1. If the subject's evaluation does not meet eligibility criteria, any result obtained between C3 and C4 can be used

∙ Please note: All 'Initial' Exclusion Criteria must be re-confirmed prior to randomization.