Inclusion Criteria:

          1. Patient must have unresectable or metastatic HCC with Childs Pugh status A with
             histologic confirmation.

             i) Subjects with only a radiologic diagnosis of HCC may be enrolled for screening in
             the study but histological confirmation is mandatory prior to the start of study
             therapy.

             ii) Evaluable tumor tissue (formalin-fixed, paraffin embedded archival or recent
             acquisition) must have 15 unstained slides for correlative studies. If archived
             samples are not available, subjects must consent to a pre-treatment fresh biopsy as a
             condition of protocol participation.

          2. Patients must have failed Sorafenib or Lenvatinib due to disease progression or
             intolerance.

          3. Presence of radiographically measurable disease based on RECIST v1.1.

          4. No evidence of biliary duct obstruction, unless obstruction is controlled by local
             treatment or, in whom the biliary tree can be decompressed by endoscopic or
             percutaneous stenting with subsequent reduction in bilirubin to below 1.5 x upper
             level of normal (ULN).

          5. Patients age ≥ 21 years at the time of written informed consent.

          6. Patients with Eastern Cooperative Oncology Group (ECOG) performance status of 0-2.

          7. Patient must be able to understand and willing to sign the informed consent form and
             donate tumor tissue (archival or fresh) for evaluation of relevant exploratory
             endpoints.

          8. Patient with adequate organ and hematological function:

             a. Hematological function, as follows: i. Absolute neutrophil count (ANC) ≥ 1.5 x
             109/L ii. Platelet count ≥ 80 x 10^9/L b. Renal functions, as follows: i. Serum
             creatinine ≤ 1.5x ULN or eGFR > 60 mL/min/1.73m2 c. Hepatic function in addition to
             Childs Pugh score A: i. Total bilirubin ≤ 1.5 x ULN ii. AST and ALT ≤ 2.5 x ULN

        Expansion cohort

          1. Patients must agree to a post treatment biopsy

          2. HER3 expression on IHC

          3. Other inclusion criteria as above

        Exclusion Criteria:

          1. Patient with radiation or local treatment within the past 6 weeks for the target
             lesion(s).

          2. Patients with major surgical procedures within 21 days prior to study entry.

          3. Patient with brain lesion, known brain metastases (unless previously treated and well
             controlled for a period of at least 3 months).

          4. Patient with malabsorption syndrome, diseases significantly affecting gastrointestinal
             function, resection of the stomach or small bowel, or difficulty in swallowing and
             retaining oral medications.

          5. Patients with an uncontrolled intercurrent illness including, but not limited to,
             ongoing or active infection, unstable angina pectoris, cardiac arrhythmia, diabetes,
             hypertension, or psychiatric illness/social situations that would limit compliance
             with study requirements.

          6. Patients with any history of other malignancy unless in remission for more than 1
             year. (Non-melanoma skin carcinoma and carcinoma-in-site of uterine cervix treated
             with curative intent is not exclusionary).

          7. Female patients who are pregnant or breast feeding.

          8. Patients who were previously treated with ASLAN001 (Varlitinib).

          9. Patients who have received any investigational drug (or have used an investigational
             device) within the last 14 days before receiving the first dose of study medication.

         10. Patient with unresolved or unstable serious toxicity ( ≥ CTCAE 4.03 Grade 2) from
             prior administration of another investigational drug and/or prior cancer treatment.

         11. Patients with a known history of HIV, decompensated cirrhosis, chronic active
             hepatitis or chronic persistent hepatitis.

         12. Patients who need continuous treatment with proton pump inhibitors during the study
             period.

         13. Any history or presence of clinically significant cardiovascular, respiratory,
             hepatic, renal, hematologic, gastrointestinal, endocrine, immunologic, dermatologic,
             neurologic or psychiatric disease or any other condition which in the opinion of the
             Investigator could jeopardize the safety of the patient or the validity of the study
             results