A Study to Investigate Safety, Tolerability, PK and Anti-tumor Activity of TRX-221 in EGFRm NSCLC Patients

Inclusion Criteria: 1. Patients with ECOG performance status score of 0 or 1 2. Histologically or cytologically confirmed diagnosis of relapsed or refractory, locally unresectable advanced or metastatic NSCLC harboring an activating EGFR mutation 3. Failed standard of care treatments progressed after anti tumor treatments including at least 1 approved EGFR TKI \[Phase2: TKIs should include the approved EGFR TKIs with activity against T790M (e.g., osimertinib)\] 4. Slots may be reserved for patients with certain resistant mutations (i.e., EGFR C797X mutation with or without T790M mutation as required by the sponsor) \[Phase 1\] 5. EGFR C797X mutation with or without T790M mutation \[Phase 2\] 6. Not received more than 1 prior line of platinum based chemotherapy in the metastatic setting \[Phase 2\] 7. Having at least 1 measurable tumor lesion per RECIST v1.1 criteria \[Phase 2\] 8. Having adequate bone marrow, hepatic, and renal function as specified in the protocol Exclusion Criteria: 1. NSCLC with mixed cell histology or a tumor with histologic transformation of small cell elements 2. Patients having tumor with any additional known driver of alterations 3. Patients with presence of another active primary malignant tumor that has been diagnosed or required therapy within 2 years prior to the initiation of the study treatment 4. Patients who have unstable and symptomatic primary CNS tumors/metastasis, leptomeningeal metastases or spinal cord compression which are not suitable for enrollment, as judged by the Investigator 5. Patients having clinically active ongoing ILD of any etiology 6. Clinically significant cardiac conditions, infections, refractory GI diseases as specified in the protocol 7. Patients having any unresolved toxicities from prior anti tumor therapy and surgery greater than CTCAE Grade 1 at the time of starting the study treatment 8. Recent anticancer therapy: EGFR-TKI, Immunotherapy or any other systemic anticancer therapy or radiotherapy (specific duration prior to starting study medication per protocol)