Inclusion Criteria:

          -  Subjects with advanced solid tumors who are refractory to or intolerant of established
             therapy known to provide clinical benefit for their condition (i.e., subjects must not
             be candidates for regimens known to provide clinical benefit).

          -  Measurable or evaluable disease

          -  Subjects must have recovered from all toxicity associated with previous chemotherapy,
             targeted therapy, experimental therapy, biological therapy, immuno-oncology therapy,
             surgery, radiotherapy, or other locoregional therapy. (Exception: Subjects may enter
             with continuing alopecia.) The following intervals must elapse between end of last
             treatment and receiving the first dose of SM08502:

               1. Chemotherapy: 3 weeks

               2. Mitomycin C or a nitrosourea: 6 weeks

               3. Radiotherapy: 6 weeks

               4. Major surgery: 6 weeks

               5. Targeted therapy, including monoclonal antibodies and immuno-oncology therapies:
                  4 weeks or 5 half-lives, whichever is shortest

               6. Hormonal therapy: 4 weeks or 5 half-lives, whichever is shortest

               7. Experimental therapy: 4 weeks or 5 half-lives, whichever is shortest

               8. Other locoregional therapy [e.g., radiofrequency ablation (RFA), TACE
                  (transarterial chemoembolization), TARE (transarterial radioembolization),
                  DEB-TACE (drug eluting bead transarterial chemoembolization)]: 6 weeks

          -  Life expectancy > 3 months

          -  Subjects must have no uncontrolled intercurrent illness

          -  Subjects must have the ability to swallow and retain oral medication

          -  Subjects must be willing to avoid extensive sun exposure, phototherapy, and use of a
             tanning salon during trial participation.

          -  Subjects must be willing to sign and provide informed consent and be capable of giving
             informed consent in accordance with the Institutional Review Board/Ethics Committee
             policy

        Exclusion Criteria:

          -  Women who are pregnant or lactating

          -  Women of childbearing potential who are sexually active and are not willing to use a
             highly effective method of birth control during the study period

          -  Males who are sexually active and not willing to use a condom, and have a partner who
             is capable of becoming pregnant, if neither has had surgery to become sterilized,
             and/or who are not willing to use double barrier or whose partner is not using a
             highly effective method of birth control

          -  Subjects with myocardial infarction (heart attack) within 1 year

          -  Subjects using agents known to inhibit or induce CYP3A4, such as ketoconazole,
             itraconazole, erythromycin, or rifampin, within 7 days prior to study start

          -  Subjects with active infection requiring antibiotic therapy

          -  Organ transplant recipients

          -  Subjects with brain metastasis

          -  Subjects with history of osteoporosis

          -  Subjects with known active human immunodeficiency virus, hepatitis B virus, or
             hepatitis C virus infection

          -  Subjects with any retinal abnormalities, including subjects with diabetic retinopathy,
             macular degeneration, or other known forms of retinal degenerative disease

          -  Subjects with chronic liver disease or dysfunction