A Study of TAS2940 in Participants With Locally Advanced or Metastatic Solid Tumor Cancer

Inclusion Criteria:

• Have histologically confirmed solid cancer that is locally advanced and metastaticand available standard treatment options have been exhausted

• Have adequate organ function

• ECOG PS 0-1

Dose Escalation:

• Have measurable or non- measurable disease per RECIST criteria v1.1 or RANO

• Any solid tumor with EGFR and / or HER2 aberration

Dose Expansion:

• Have measurable disease per RECIST criteria v1.1 for solid tumor (excluding primarybrain tumor) or RANO (for glioblastoma)

• Cohort A: Non-small cell lung cancer (NSCLC)

• Cohort B: HER2 positive breast cancer

• Cohort C: Recurrent or refractory glioblastoma

• Cohort D: Other solid tumors with EGFR or HER2 aberrations

Exclusion Criteria:

• Non-stable brain metastases

• Have significant cardiovascular disorder

• Have not recovered from prior cancer treatment

• A serious illness or medical condition