Inclusion Criteria:

          -  Advanced stage solid tumors as documented by histological or cytological evidence,
             with no available approved therapies known to cure metastatic disease or extend
             survival, and who have received all standard therapy.

          -  Documented disease progression following prior therapy, as assessed by the
             Investigator.

          -  Eastern Cooperative Oncology Group (ECOG) 0 or 1.

          -  Evaluable or measurable disease as defined by RECIST v1.1 may be enrolled in the dose
             escalation part; for the dose confirmation part, subjects must have measurable disease
             by RECIST v1.1 or biomarker for response.

          -  Males and females ≥ 18 years of age.

          -  Able to give written informed consent.

          -  Able to swallow tablets.

          -  Willing and able to comply with scheduled visits, treatment plans, laboratory tests
             and procedures.

          -  Acceptable liver function:

               -  Bilirubin ≤ 1.5 times the upper limit of normal (ULN),

               -  Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤ 3 times the
                  ULN; if liver metastases are present, then ≤ 5 times the ULN is allowed.

          -  Acceptable renal function:

             *Serum creatinine ≤ 1.5 times the ULN.

          -  Acceptable hematologic status (without growth factor support or transfusion
             dependency):

               -  Absolute neutrophil count (ANC) ≥ 1,500 cells/μL,

               -  Platelet count ≥ 100,000/μL,

               -  Hemoglobin ≥ 9.0 g/dL.

          -  QTc interval calculated according to Fridericia's formula (QTcF = QT/RR0.33; RR = RR
             interval) of ≤ 450 msec on screening electrocardiogram (ECG).

          -  Must have a normal ejection fraction (within the reference range of the institution)
             and no clinically significant valvular dysfunction.

          -  Must have discontinued cancer treatments, including experimental agents for 28 days or
             a minimum of 5 half-lives (for any biologics) prior to the start of treatment.
             Enrollment after exposure levels of a biologic have fallen below an active level as
             established in the summary basis of approval is acceptable.

          -  Must have discontinued radiotherapy at least 14 days with resolution of any toxicity
             to Grade 1 or better prior to the start of treatment.

          -  A life expectancy of at least 3 months as assessed by the Investigator.

          -  Female subjects of childbearing potential must have a negative serum pregnancy test
             within 7 days of the first administration of study drug. For the purpose of this
             study, female subjects of childbearing potential are defined as all female subjects
             after puberty unless they are postmenopausal for at least 1 year, or are surgically
             sterile (hysterectomy or bilateral oophorectomy or tubal ligation).

        Exclusion Criteria:

          -  Elevated Troponin 1 levels at screening or known to have persistently elevated brain
             natriuretic peptide (BNP).

          -  Serious pre-existing medical conditions as follows:

               -  Myocardial infarction within 6 months prior to screening, or pericardial
                  effusion,

               -  History of cardiac or aortic surgery,

               -  Serious arrhythmia,

               -  Unstable angina pectoris,

               -  Congestive heart failure of New York Heart Association class III/IV,

               -  Hypertension that is not controlled by standard medication (to 150/90 mmHg or
                  below),

               -  Cirrhosis of the liver, Child-Pugh Stage B or C, or history of liver transplant,

               -  Severe diabetes that is not currently controlled,

               -  Current or history of interstitial pneumonitis,

               -  Presence of aneurisms of the ascending aorta or aortic stress.

          -  Uncontrolled metastatic disease to the brain or central nervous system (CNS).

          -  Known history of difficulty swallowing, malabsorption or other conditions that may
             reduce absorption of the product.

          -  Received prior treatment targeting the signaling pathway of TGF-β.

          -  Major abnormalities identified by ECG or echocardiogram (ECHO), at the Investigator's
             discretion.

          -  Known infection of, or who test positive for, human immunodeficiency virus, hepatitis
             B virus or hepatitis C virus.

          -  Active infection requiring systemic antibiotic therapy.

          -  Known substance abuse or receiving concurrent treatment with non-permitted drugs.

          -  Female subjects who are breastfeeding, or intend to breastfeed during the duration of
             the study and for 30 days following the last dose of study drug.

          -  Known history, or suspected hypersensitivity to any excipients.

          -  Female subjects must not be pregnant or at risk to become pregnant during the study.
             Fertile male and female subjects must agree to use an effective barrier method of
             birth control to avoid pregnancy (for female subjects a double-barrier method of
             contraception, for male subjects a condom with spermicide) or total abstinence from
             the time of providing informed consent until 90 days after the last administration of
             study drug. Use of oral contraceptives is not allowed.

          -  Any other serious medical condition which in the Investigator's opinion would preclude
             safe participation in the study.

          -  Subjects, in the opinion of the Investigator, who are unsuitable to participate in the
             study.

          -  Currently using or planning to use:

               -  Drugs which are exclusively or primarily eliminated by cytochrome P-450 isozyme
                  3A4 (CYP)3A4.

               -  Drugs which are exclusively or primarily eliminated by UDP glucuronyltransferase
                  1A1 (UGT)1A1.

               -  Drugs which are substrates for the drug transporter multidrug resistance protein
                  1 (MDR1) have a narrow therapeutic window; or which are strong inhibitors of drug
                  transporter MDR1.

          -  Any major surgeries within 28 days.