Study to evaluate the safety and tolerability of the study drug CLN-418, to determine the maximum tolerated dose and/or recommended Phase 2 study dose of CLN-418.

This is a study to evaluate the safety and tolerability of the study drug CLN-418, and to determine the maximum tolerated dose and/or recommended Phase 2 study dose of CLN-418.

The study will also look at the anti-tumor activity, pharmacokinetics and immunogenicity of CLN-418.The study consists of 2 parts. In Part 1, patients are enrolled into different cohort doses in order to identify the appropriate recommended phase 2 dose (RP2D) or maximum tolerated dose (MTD). In Part 2, participants with metastatic / unresectable Non small cell lung cancer (NSCLC), Triple Negative Breast Cancer (TNBC) will receive the maximum tolerated dose (MTD) and/or recommended phase 2 dose (RP2D) established in Part 1 of the study. In Part 1 and Part 2, participants will be administered treatment every 3 weeks.

Inclusion Criteria:

1. Willingness to sign a written informed consent document.
2. Male or female subject aged ≥18 years old at the time of screening.
3. Histologically or cytologically confirmed advanced solid tumors (e.g., breast cancer, ovarian cancer, endometrial cancer, cervical cancer, squamous cell non-small cell lung cancer (sNSCLC), cholangiocarcinoma, esophagus cancer, urothelial carcinoma, head and neck squamous cell carcinoma (HNSCC)), followed by dose-expansion cohorts (Part 2) of subjects with advanced and/or metastatic non-small cell lung cancer (NSCLC), triple-negative breast cancer (TNBC).or recurrent and progressed since last antitumor therapy for which no alternative, curative standard therapy exists.
4. Adequate organ and bone marrow function.

Exclusion Criteria:

1. Prior used anti-B7H4 and/or anti-4-1BB antibody treatment.
2. Immuno-oncology therapy or targeted anti-cancer therapy within 4 weeks prior to first dose of investigational product, any other anti-cancer therapy within 2 weeks prior to first dose of investigational product.
3. Not yet recovered from surgery or (immune-related) toxicity related with previous treatment.
4. Known history or active infection of hepatitis B or C.
5. History of cirrhosis or non-alcohol steatohepatitis, alcohol or drug-related, autoimmune hepatitis.
6. Known brain metastases or other central nervous system metastases that are either symptomatic or untreated that require concurrent treatment.
7. Active infection that requires treatment with antibiotics or antiviral treatment within 3 weeks prior to first dose of investigational product.
8. Known history of infection with human immunodeficiency virus or known acquired immunodeficiency syndrome (AIDS).
9. Known autoimmune disease.
10. Clinically significant cardiac condition.
11. Pregnant or breastfeeding women.

Data generated by this study will be considered confidential by the Investigator, except to the extent that it is included in a publication. The general strategy regarding publication of the study will be mutually agreed upon by the Investigator and Sponsor. The Sponsor reserves the right to manage the publication of all study results. The Investigator agrees that oral and written communication to third parties of any procedures or results from the study is subject to prior written consent of the Sponsor. Presentation material and/or manuscript(s) for publication will be reviewed by the Sponsor prior to submission for publication. Alterations in the material will only be made in agreement between the Investigator and the Sponsor