The purpose of this trial is to find the maximum tolerated and recommended Phase 2 dose of KUP-101A and to evaluate its safety and tolerability. Additionally, pharmacokinetics and pharmacodynamics will be assessed, and first data on KUP-101A's efficacy in patients with advanced solid tumors will be obtained.

Inclusion Criteria:

• Histologically confirmed cancer with evidence of advanced disease for which no other standard treatment is available
• ECOG Performance status of 0 to 2
• Adequate hematological, renal, and hepatic organ function

Exclusion Criteria:

• Previous systemic treatment with TLR agonists, with the exception of TLR agonists used as vaccine adjuvants.
• Known additional malignancy that is progressing or requires active treatment
• Diagnosis of immunodeficiency
• Active autoimmune disease not caused by prior anticancer treatment that required systemic immunosuppressive treatment in the past 2 years
• Active autoimmune disease caused by prior anticancer treatment, unless currently controlled by replacement therapy only.
• Any kind of leukemia
• Previously received an organ transplant (other than corneal transplants) or hematopoietic stem cell transplantation
• Known active central nervous system metastases and/or carcinomatous meningitis
• Cerebral vascular event within 6 months before Screening
• Unstable cardiopulmonary status defined by uncontrolled congestive heart failure of New York Heart Association Grade III or IV, unstable angina, or myocardial infarction within 6 months before Screening
• High grade ocular disease such as uncontrolled glaucoma