A First-in-human (FIH), Phase I Study of PTX-912 in Patients with Locally Advanced/Metastatic Solid Tumors

Inclusion Criteria:

1. Willing and able to provide signed and dated informed consent prior to anystudy-related procedures and willing and able to comply with all study procedures.

2. Male and Female patients age ≥ 18 years on day of signing informed consent.

3. Willing to comply with all protocol-required visits, assessments, and procedures.

4. Patients with locally advanced or metastatic solid tumors who have had diseaseprogression on all available standard of care or for whom no reasonable standard ofcare exists that would confer clinical benefit.

5. Recovery from all toxicities associated with prior therapy to acceptable baselinestatus (for laboratory toxicities, see limits for inclusion). NCI CTCAE v5.0 Grade 0or 1, except for toxicities not considered a safety risk (e.g., alopecia orvitiligo).

6. Measurable disease per RECIST v1.1.

7. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 with nodeterioration during Screening.

8. Adequate bone marrow and organ function, defined by the following laboratory resultsobtained within 14 days before first dose of study drug.

9. Patients with recent major surgery must have adequately recovered with no ongoingcomplications from the surgery prior to receiving study treatment.

10. Willingness to adhere to the study treatment-specific contraception requirements.

11. Estimated life expectancy of 3 months (12 weeks) or greater as determined byInvestigator.

Exclusion Criteria:

1. Has a diagnosis of immunodeficiency.

2. Has an active infection requiring systemic therapy within 4 weeks prior to studytreatment.

3. History of or known intolerance, significant hypersensitivity, or anaphylaxis to anycomponents of PTX-912 or any of the excipients.

4. Unresolved toxicities from prior systemic therapy greater than NCI CTCAE grade 1 attime of first dose, except alopecia, vitiligo, and grade 2 neuropathy due to priorchemotherapy.

5. Experienced clinically significant immune-related toxicity from prior immunotherapythat in the opinion of the investigator would preclude protocol therapy or wouldmake the patient inappropriate for the study.

6. Major surgery within 30 days prior to first dose of study drug (with the belowexceptions), or anticipation of major surgery during study treatment.

7. Active autoimmune disease requiring systemic treatment within the past 3 months orhave a documented history of clinically severe autoimmune disease that requiressystemic steroids or immunosuppressive agents.

8. Uncontrolled diabetes mellitus or other uncontrolled immune-related endocrinopathiesin the opinion of the investigator.

9. Primary central nervous system (CNS) disease or leptomeningeal disease.

10. Impaired cardiovascular function or clinically significant cardiovascular disease.

11. Abnormal pulmonary function within the previous 6 months, including history ofpneumonitis, active pneumonitis, interstitial lung disease requiring the use ofsteroids, idiopathic pulmonary fibrosis, active pleural effusion, severe dyspnea atrest or requiring supplementary oxygen therapy.

12. History of allogenic, bone marrow, or solid organ transplants.

13. Received a live-virus vaccination ≤14 days prior to first dose of study drug (seasonal flu and other inactivated vaccines that do not contain live virus arepermitted).

14. Clinically significant bleeding within 2 weeks prior to first dose of study drug dy.

15. Pregnant or breast-feeding women or expecting to conceive within the projectedduration of the trial, starting with the screening visit through 3 months after thelast dose of study drug.