This is a phase I, open-label, multicenter study to assess the safety, tolerability, pharmacokinetics and preliminary antitumor activity of PLB1004, and to determine the maximum tolerated dose (MTD), dose-limiting toxicities (DLTs) and recommended phase II dose (RP2D).

The study includes a Dose-escalation Part and a Dose Expansion Part. The aim of the Dose-escalation Part is to estimate the MTD (if possible), identify the DLT (if possible) and the RP2D for PLB1004. The Dose Expansion Part is to further assess the clinical efficacy and safety of PLB1004.

Inclusion Criteria:

1. Ability to understand and the willingness to sign a written informed consent document；
2. Aged at least 18 years old;
3. Histologically or cytologically confirmed advanced non-small cell lung cancer;
4. Patients with EGFR or HER2 mutations;
5. ECOG Performance Status of 0-2;
6. Life expectancy is not less than 12 weeks;
7. At least one measurable lesion as defined by RECIST1.1;

Exclusion Criteria:

1. For the Dose Expansion Part: Patients who have received prior treatment with Poziotinib or TAK788 or other EGFR/HER2 exon20 insertion inhibitors should be excluded；

2. Any cytotoxic drugs or other anticancer drugs from a previous treatment regimen within 14 days prior to the first dose of PLB1004；

3. Major surgery (e.g., intra-thoracic, intra-abdominal or intra-pelvic) within 4 weeks prior (2 weeks for resection of brain metastases) to starting PLB1004 or who have not recovered from side effects of such procedure;

4. Thoracic radiotherapy to lung fields ≤ 4 weeks prior to starting PLB1004. For all other anatomic sites (including radiotherapy to thoracic vertebrae and ribs), radiotherapy ≤ 2 weeks prior to starting PLB1004 or patients who have not recovered from radiotherapy-related toxicities. Palliative radiotherapy for bone lesions ≤ 2 weeks prior to starting PLB1004 is allowed;

5. Patients receiving treatment with medications that meet one of the following criteria and that cannot be discontinued at least 1 week prior to the start of treatment with PLB1004 and for the duration of the study:

   • Strong inhibitors of CYP3A4
   • Strong inducers of CYP3A4
   • Inducers or inhibitors of P-gp

6. Patients with symptomatic central nervous system (CNS) metastases who are neurologically unstable or have required increasing doses of steroids within the 2 weeks prior to study entry to manage CNS symptoms;

7. Clinically significant, uncontrolled heart diseases;

8. Presence or history of a malignant disease other than NSCLC that has been diagnosed and/or required therapy within the past 3 years. Exceptions to this exclusion include the following: completely resected basal cell and squamous cell skin cancers, indolent malignancies that currently do not require treatment, and completely resectedcarcinoma in situ of any type;

9. Past medical history of interstitial lung disease, drug-induced interstitial lung disease, radiation pneumonitis which required steroid treatment, or any evidence of clinically active interstitial lung disease;

10. History of hypersensitivity to active or inactive excipients of PLB1004 or drugs with a similar chemical structure or class to PLB1004;

11. Pregnant or nursing women;

12. Judgment by the investigator that the patient should not participate in the study if the patient is unlikely to comply with study procedures, restrictions and requirements;