Inclusion Criteria:

          -  Signed written informed consent

          -  Male and female adults ≥18 years of age

          -  Histologically or cytologically confirmed solid tumor that is metastatic or
             unresectable and for which standard curative or palliative measures do not exist or
             are no longer effective

          -  Topotecan monotherapy is a reasonable treatment in the judgement of the Investigator

          -  Measurable disease as per RECIST v1.1 criteria

          -  Able to swallow oral medication as an intact dosage form

          -  Adequate hematologic status as demonstrated by not requiring transfusion support or
             granulocyte colony-stimulating factor (G-CSF)levels maintained

          -  Adequate liver function.

          -  Adequate renal function

          -  Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1

          -  Life expectancy of at least 3 months

          -  Females must be postmenopausal (>12 months without menses) or surgically sterile (ie,
             by hysterectomy and/or bilateral oophorectomy) or, if sexually active, must be using
             effective contraception (ie, oral contraceptives, intrauterine device, double barrier
             method of condom and spermicide) and agree to continue use of contraception for 30
             days after their last dose of study drug.

          -  Sexually active male patients must use a barrier method of contraception during the
             study and agree to continue the use of male contraception for at least 30 days after
             the last dose of study drug.

        Exclusion Criteria:

          -  Currently taking a prohibited concomitant medication, other than a premedication, that
             are Strong inhibitors or strong inducers of cytochrome P450

          -  Unresolved toxicity from prior chemotherapy

          -  Planning to receive other medical, surgical, or radiological cancer treatments during
             the course of this study

          -  Received investigational agents within 14 days or 5 half-lives prior to the first
             study dosing day, whichever is longer

          -  Require therapeutic use of anticoagulants.

          -  Uncontrolled intercurrent illness including, but not limited to, ongoing or active
             infection, symptomatic congestive heart failure, clinically significant myocardial
             infarction unstable angina pectoris, clinically significant cardiac arrhythmia,
             bleeding disorder, chronic pulmonary disease requiring oxygen, or psychiatric
             illness/social situations that would limit compliance with study requirements.

          -  Major surgery to the upper GI tract

          -  Hypersensitivity to topotecan or allergy to HM30181A or its excipients.

          -  Any other condition which the Investigator believes would make participation in the
             study not acceptable