Inclusion
1. Diagnosis of a histologically or cytologically confirmed locally advanced or metastatic cancer (all solid tumors). Subjects must be considered refractory or intolerant to the standard of care therapies or have refused standard therapy.
2. Age greater than or equal to 18 years old at the time of Screening (signing the Informed Consent Form [ICF]).
3. Eastern Cooperative Oncology Group performance status 0 to 1.
4. The estimated life expectancy of at least 3 months as per the Investigator's judgment.
5. At least one measurable disease tumor lesion by Response Evaluation Criteria in Solid Tumors Version 1.1
6. Subjects who have undergone treatment with an anti-PD-1, anti-PD-L1, or anti-CTLA-4 antibody must have a gap of at least 4 weeks from the last dose of antibody and evidence of disease progression per the Investigator's assessment before enrollment.
7. Subjects who have previously received an immune CPI prior to enrollment must have any immune-related toxicities resolved to less than or equal to Grade 1 or baseline (prior to the CPI) with the exception of toxicities not considered a safety risk (eg, alopecia, neuropathy, or asymptomatic laboratory abnormalities).
8. Adequate organ function based on laboratory assessments at Screening, as defined by:
• Hemoglobin greater than or equal to 90 g/L (subjects may be transfused >2 weeks before Screening, but should not be transfusion-dependent)
• Platelets greater than or equal to 100 × 109/L
• Absolute neutrophil count greater than or equal to 1.5 × 109/L
• Serum creatinine less than or equal to 1.5 × upper limit of normal (ULN); or a calculated creatinine clearance (Cockcroft-Gault method) greater than or equal to 50 mL/minute if serum creatinine >1.5 × ULN. Lower calculated creatinine clearance values may be allowed at the Investigator’s discretion and in consultation with the Medical Monitor and Sponsor.
• Total bilirubin less than or equal to ULN; or conjugated bilirubin less than or equal to ULN and total bilirubin less than or equal to 1.5 × ULN (<3.0 × ULN for subjects with liver metastases or Gilbert’s syndrome)
• Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) less than or equal to 3 × ULN (AST and ALT less than or equal to 5 × ULN if liver metastases present)
• International normalized ratio and activated partial thromboplastin time less than or equal to 1.5 × ULN.
9. Available archived tumor tissue sample (block of formalin-fixed paraffin-embedded [FFPE] tissues) to allow for exploratory biomarker studies. In the setting where archival material is unavailable or unsuitable for use (eg, recently diagnosed subjects or diagnosed with fine-needle aspiration), the subject will have an option to consent for and undergo fresh tumor biopsy (at acceptable risk as judged by the Investigator). The requirement for fresh biopsy collected from a given subject could be waived after the discussion with the Medical Monitor if the tumor tissues are not safely accessible as determined by the Investigator or the tumor biopsies have to be obtained from sites that require significant risk procedures.
10. Female subjects must not be pregnant, or must be of non-childbearing potential; or if of childbearing potential, must agree to use highly effective birth control methods during the study treatment period and for at least 90 days after the last dose of the study treatment.
Non-sterilized male subjects must agree to use contraception during the treatment period and for at least 90 days after the last dose of the study treatment.
11. For women of childbearing potential (WOCBP) only: A negative serum pregnancy test during Screening and a negative serum or urine pregnancy test within 24 hours of the first dose of study treatment.
12. Voluntarily agrees to participate by giving written informed consent and is willing and able to comply with this protocol and scheduled visits.
Exclusion
1. Subjects diagnosed with glioblastoma, other brain tumors, and hematological cancer. In the case of rare cancers, there may be some exceptions at the Investigator’s discretion in consultation with the Medical Monitor.
2. Prior malignancies active within previous 3 years, except the cancer for which the subject is enrolled in the current study or locally curable cancers that have been cured (eg, basal cell skin cancer, squamous cell carcinoma, or carcinoma in situ of the cervix or breast).
3. Known active central nervous system metastases or carcinomatous meningitis.
4. Active autoimmune disease or a history of autoimmune disease, except for vitiligo, resolved childhood asthma/atopy, current mild asthma (treated with intermittent bronchodilators only), mild atopic dermatitis (treated with topical medications only), and endocrine deficiency following immunotherapy.
5. Current or known history of rheumatoid arthritis, ankylosing spondylitis, or any other joint inflammatory conditions that have systemic and/or organ involvement, and/or involve disease flares affecting joint function. Osteoarthritis alone is not exclusionary. For uncertain cases, final determination can be made as per the discretion of the PI in consultation with the Medical Monitor.
6. Active systemic infection requiring treatment with intravenous antibiotics or a significant infection (minor superficial skin infections or urinary tract infections are not exclusionary).
7. History of a severe hypersensitivity reaction to another biological therapy.
8. History of syncope.
9. Have uncontrolled pleural effusion(s), pericardial effusion, or ascites.
10. Evidence of abnormal cardiac function as defined by any of the following:
• Myocardial infarction within 6 months of Cycle 1 Day 1.
• Symptomatic congestive heart failure (New York Heart Association Class II or greater).
• Unstable angina.
11. Received chemotherapy, radiation therapy, or other anticancer therapy within 4 weeks prior to the first dose of study treatment. Exceptions include concurrent use of hormones for noncancer-related conditions (eg, insulin for diabetes and HRT), androgen deprivation therapy for prostate cancer, and local treatment of isolated lesions for palliative intent (eg, by local surgery or local radiotherapy).
12. Received prior TLR agonist therapy.
13. Currently taking chronic systemic glucocorticoid therapy in excess of replacement doses (ie, >10 mg prednisone/day or equivalent) or other systemic immunosuppressive treatment.
14. Have undergone major surgery in the 4 weeks prior to Screening or minor surgical procedures less than or equal to 7 days (no waiting required following port-a-cath placement or for venous access).
15. Received investigational therapy or used an investigational device within 4 weeks prior to the first dose of study treatment.
17. Pregnant or breastfeeding or expecting to conceive a child during the study or within 90 days after the last dose of study treatment.
18. Known history of human immunodeficiency virus infection or active infection with hepatitis B or C.
19. Have a psychiatric or substance use disorder that would interfere with cooperation with the requirements of the study.
20. History of any condition or treatment which could confound the results of the study, interfere with the subject’s participation in the study, or make study participation not in the subject’s best interests, in the opinion of the Investigator.