Safety and Tolerability of HTI-1066 in Subjects With Advanced Solid Tumors

This is a 2-part dose escalation and dose expansion study. Dose escalation uses a modified
"3+3" design and continues until a maximum tolerated dose (MTD) or recommended phase 2 dose
(RP2D) is identified. In part 2, subjects with selected tumor types will be enrolled at the
MTD or RP2D.

Inclusion Criteria:

1. Male or female ≥18 years of age

2. Subject must have an advanced solid tumor

3. ECOG Performance Status of 0 or 1

4. Life expectancy ≥12 weeks

5. Adequate laboratory parameters

6. Female subjects agree not to be pregnant or lactating from beginning of the study
screening until 4 months after receiving the last treatment; Male and female subjects
and their sexual partners are willing and able to employ a highly effective method of
birth control/contraception.

7. Willing and able to comply with clinic visits and study-related procedures

8. Provide signed informed consent

Exclusion Criteria:

1. Hypersensitivity to HTI-1066 or sensitivity to humanized monoclonal antibody products

2. Any concurrent therapy for cancer, radiation, or surgery within 4 weeks, except for
minor palliative intent (this is to be discussed with sponsor)

3. Any concurrent use of anti-infective, anti-fungal, or anti-viral agent (exceptions are
to be approved by the sponsor)

4. Any other prohibited or restricted medication as described in the study protocol.

5. Investigational therapy administered <5 half-lives before the first dose of HTI-1066

6. Any anticancer therapy administered <5 half-lives before first dose of HTI-1066; any
prior immune-oncology products administered within 4 weeks or 5 half-lives before the
first dose of HTI-1066 as described above; or surgery or radiotherapy administered
within 4 weeks before the first dose of HTI-1066.

7. Active CNS metastases.

8. Cardiac disease (NYHA classes II-IV) including myocardial infarction within 6 months
before enrollment, or unstable angina, congestive heart failure, or cardiac arrhythmia
requiring treatment.

9. History or presence of an abnormal ECG, ECHO, or MUGA that is clinically meaningful.

10. History of immunodeficiency including seropositivity for human immunodeficiency virus
(HIV), or other acquired or congenital immune-deficient disease, or any active
systemic viral infection requiring therapy (e.g., hepatitis B or C)

11. Any other medical, psychiatric, or social condition deemed by the investigator to be
likely to interfere with a subject's rights, safety, welfare or ability to sign
informed consent, cooperate and participate in the study, or interfere with the
interpretation of the results

12. Active infection or an unexplained fever >38.5°C during Screening or on the first
scheduled day of dosing.

13. Unresolved toxicities from previous anticancer therapy.