∙ Subjects who participate in the study must meet all of the following inclusion criteria.

• Adults ≥19 years old at the time of written informed consent

• Patients with histologically/cytologically confirmed metastatic/recurrent colorectal cancer after failure of, or not eligible for oxaliplatin and irinotecan-based standard anticancer therapy (If a subject had a radical surgery for colorectal cancer followed by adjuvant anticancer therapy, and the disease recurred during the adjuvant anticancer therapy or within 6 months from the end of the adjuvant anticancer therapy, the adjuvant anticancer therapy will be considered primary palliative therapy.)

• Subjects with at least one evaluable lesion, or non-measurable but evaluable lesion according to RECIST v1.1

• Subjects with ECOG performance status 0-1

• Subjects with adequate bone marrow and body organ functions

‣ Absolute neutrophil count (ANC) ≥ 1.5 x 109/L

⁃ Hemoglobin count (Hgb) ≥ 9.0 g/dL

⁃ Platelet count ≥ 100 x 109/L

⁃ Serum creatinine ≤ ULN x 1.5 or serum creatinine clearance \> 30mL/min

⁃ Total bilirubin ≤ 1.5 x ULN (Subjects with biliary obstruction may be enrolled if they meet the criterion after adequate biliary drainage.)

⁃ AST and ALT ≤ 3 x ULN in the absence of liver metastasis; or AST and ALT ≤ 5 x ULN in the presence of liver metastasis

• Subjects with adequate cardiac function at the screening visit

‣ QTc calculated using the Fredericia formula ≤ 480 msec (Those with QTc \>480 msec may be enrolled if the mean of 3 consecutive QTc measurements is \<480 msec.)

• A negative serum β-HCG test within 14 days prior to IP dosing for women of childbearing potential

• Subjects who agree, and are able to use during the study medically reliable methods of contraception as follows

‣ To be eligible for enrollment, women of childbearing potential (all women who can have physiological pregnancy during IP treatment and for 6 months after the end of IP treatment unless they use appropriate methods of contraception) must use the following methods of contraception.

⁃ Subjects must refrain from any type of sexual intercourse, and persistent abstinence in daily life is recommended. Periodic abstinence (e.g., rhythm method, cervical mucus method, basal body temperature method, etc.) and withdrawal method are not acceptable methods of contraception.

⁃ Female sterilization procedures: Bilateral ovariectomy with or without hysterectomy; tubal ligation within 6 weeks prior to enrollment in this study. If the subject is confirmed to have childbearing potential based on the assessment of hormone level, only bilateral ovariectomy will be permitted.

⁃ Vasectomized partner (at least 6 months prior to screening). For women who participate in the study, the vasectomized partner must be the only partner during her participation in this study.

⁃ Men must use condoms during sexual intercourse during and after IP treatment (for 6 months after the last IP dose).

• Life expectancy ≥3 months

⁃ Subjects who consent to sampling tumor tissues or collecting tumor tissue samples obtained within 2 years prior to the screening visit

⁃ Subjects who, after being fully informed of the study, voluntarily decide to participate in the study, provide written informed consent, and agree to comply with study procedures during the study

⁃ \[Inclusion criteria for the phase 2 study\] Subjects who participate in the phase 2 study must meet all of the following criteria.

⁃ Subjects with Tumor Proportion Score (TPS) ≥50 based on immunohistochemistry (IHC) at the screening visit