A Phase 1, Open-Label, Dose-Escalation, Dose-Finding Study Evaluating the Safety and Pharmacokinetics of Orally Administered SM08502 in Subjects with Advanced Solid Tumors

This study is an open-label, multi-center, dose-escalation, dose-finding and expansion study
in adult subjects with advanced solid tumors for whom no standard therapy is available. The
study will evaluate the safety, tolerability, PK, PD, and preliminary anti-tumor efficacy of
SM08502 administered orally, once daily, following a 28-day treatment cycle (Part 1A).
Alternative dosing schedules will be explored in Part 1B and the recommended Part 2 dose and
schedule will be further evaluated in Part 2.

Subjects will participate in a screening period of up to 14 days. Dosing in 28-day cycles
will continue within each subject, unless treatment is discontinued due to toxicity, disease
progression, initiation of a new anti-neoplastic therapy, withdrawal of consent, the Sponsor
terminates the study, or the subject no longer meets retreatment criteria.

Approximately 10 subjects enrolled in Part 2, irrespective of the tumor type, will be
included in a food effect substudy to assess the preliminary effect of a high-fat,
high-calorie meal on the PK of SM08502. Subjects participating in the food effect substudy
will continue on study and complete assessments as per the Part 2 schedule and receive
SM08502 at the recommended Part 2 dose (or another previously assessed dose level and
schedule).

Key Inclusion Criteria:

1. Subjects with advanced solid tumors (as defined below):

1. Part 1A - 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) and for which histologic or cytologic confirmation of malignancy was
obtained at diagnosis, with the exception of hepatocellular carcinoma if it meets
appropriate imaging-only diagnostic criteria (per the National Comprehensive
Cancer Network [NCCN], Liver Imaging Reporting and Data System [LI-RADS],
American Association for the Study of Liver Diseases [AASLD], Asian Pacific
Association for the Study of the Liver [APASL], or European Association for the
Study of the Liver - European Organisation for Research and Treatment of Cancer
[EASL-EORTC]).

2. Part 1B - Subjects with advanced and/or metastatic 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 in the Investigator's judgment). Histologic or
cytologic confirmation of malignancy must have been obtained at diagnosis. The
tumor types include: i. NSCLC (adenocarcinoma subtype) ii. TNBC iii. CRPC iv. CRC
v. Endometrial cancer (endometrioid subtype) vi. Ovarian cancer (serous,
mucinous, and endometrioid subtypes).

3. Part 2 - Subjects with advanced and/or metastatic solid tumors who are refractory
to or intolerant of established therapy known to provide clinical benefit for
their condition. Histologic or cytologic confirmation of malignancy must have
been obtained at diagnosis. Subjects must have received no more than 2 prior
lines of myelosuppressive chemotherapy. Additionally, CRPC subjects must have
received no more than 4 total lines of treatment (including any hormonal
therapies) in any setting. The tumor types include: i. NSCLC (adenocarcinoma
subtype) ii. CRPC in two biomarker selected cohorts.

2. Measurable or evaluable disease per RECIST 1.1 (Part 1A). For Parts 1B and 2, at least
1 measurable lesion per RECIST 1.1 that has not been previously irradiated. In CRPC
subjects (Parts 1B and 2) without measurable disease per RECIST 1.1, a PSA that is
concordant with clinical disease progression (rising) is eligible. A PSA value of 2
ng/ml or greater is required for study entry.

3. Subjects must have archived tumor specimens available for analysis (as specified in
Section 7.2.2). Otherwise, a fresh tumor biopsy will be required at study entry. At
the discretion of the Sponsor's Medical Monitor, a fresh tumor biopsy may not be
required for eligibility if there are extenuating circumstances (e.g., inaccessible
sites of disease or lack of subject suitability to undergo a fresh biopsy, or
molecular profiling of archived tissue already performed).

4. Subjects must have recovered (i.e., Grade 1 [or better] based on CTCAE v5.0) from all
toxicity associated with previous chemotherapy, targeted therapy, experimental
therapy, biological therapy, immuno-oncology therapy, surgery, radiotherapy, or other
locoregional therapy (Exceptions include subjects with: continuing alopecia regardless
of any CTCAE grade, Grade 2 or lower neuropathy, and well-controlled hypothyroidism
and/or adrenal insufficiency on chronic hormone replacement. All subjects with these
exceptions are eligible).

5. Eastern Cooperative Oncology Group (ECOG) performance status ≤ 1.

Key Exclusion Criteria:

1. Women who are pregnant or lactating

2. Women of childbearing potential (WOCBP) who do not agree to follow the contraceptive
guidelines as outlined in the study protocol

3. Men of reproductive potential who do not agree to follow the contraceptive guidelines
as outlined in the study protocol

4. Subjects with a corrected QT interval (QTc) using Fridericia's formula (QTcF) > CTCAE
v5.0 Grade 1 (>480 msec) based on the mean of triplicate evaluation at Screening.

5. Subjects with clinically significant ventricular tachycardia (VT), atrial fibrillation
(AF), ventricular fibrillation (VF), second or third degree heart block

6. Subjects with myocardial infarction (MI) within 1 year, Class II-IV congestive heart
failure (CHF) per New York Heart Association (NYHA) classification, or clinically
significant coronary artery disease (CAD)

7. Subjects with active infection requiring parenteral antibiotic therapy.

8. Organ transplant recipients.

9. Subjects with known osteoporosis.

10. Subjects with a second malignancy unless adequately treated with no recurrence for 3
years. Subjects with history of previous or recent adequately treated skin basal cell
carcinoma, squamous cell carcinoma of the skin, or carcinoma in situ of any source are
eligible.

11. Subjects with active gastrointestinal (GI) disease or other condition that will
interfere significantly with the absorption, distribution, metabolism, or excretion of
SM08502 per Investigator's opinion

12. Subjects with known active human immunodeficiency virus (HIV), hepatitis B virus
(HBV), or hepatitis C virus (HCV) infection

13. Subjects with chronic liver disease or dysfunction and a Child-Pugh score of B or C

14. Subjects with untreated, progressing, or known symptomatic brain metastasis

15. Subjects with retinal abnormalities, specifically diabetic retinopathy, macular
degeneration, other forms of retinal degenerative disease, or other retinal findings
that may place the subject at risk