A Study to Assess the Safety, Pharmacokinetics and Anti Tumor Activity of UCB6114 Administered Intravenously to Participants With Advanced Solid Tumors

Inclusion Criteria:

* Participant must be at least 18 years of age inclusive, at the time of signing the informed consent
* Participant has advanced disease (ie, locally advanced or metastatic)
* Participant has measurable or non-measurable disease as defined by the relevant Response Evaluation Criteria in Solid Tumors (RECIST)
* Participant has an Eastern Cooperative Oncology Group (ECOG) performance status of ≤1

Part A specific:

\- Participant has a histologically and/or cytologically confirmed diagnosis of one of the following advanced solid tumor types: colorectal adenocarcinoma, esophageal carcinoma, head and neck squamous cell carcinoma, lung adenocarcinoma, lung squamous cell carcinoma, pancreatic adenocarcinoma, prostate adenocarcinoma, stomach adenocarcinoma, bladder urothelial carcinoma, or breast invasive carcinoma

Part B and C specific:

\- Participant has a histologically and/or cytologically confirmed diagnosis of one of the following advanced solid tumor types: colorectal adenocarcinoma, gastric adenocarcinoma, or adenocarcinoma of the gastroesophageal junction

Part A1 specific:

\- Participant has histologically and/or cytologically confirmed diagnosis of one of the following advanced solid tumor types: colorectal adenocarcinoma, gastric adenocarcinoma, adenocarcinoma of the gastroesophageal junction, or pancreatic cancer

Exclusion Criteria:

* Participant has a known hypersensitivity to any components of the study medications or comparable drugs
* Active and clinically significant bacterial, fungal, or viral infection, known infections with hepatitis B, hepatitis C, known human immunodeficiency virus, or acquired immunodeficiency syndrome related illness
* Symptomatic central nervous system (CNS) malignancy or metastases. Screening of asymptomatic participants without history of CNS metastases is not required. Participants with asymptomatic CNS lesions should have completed standard therapy for their CNS lesions prior to study enrolment
* Current hematologic malignancies
* Prior organ or allogeneic stem-cell transplantation
* QT interval corrected (QTc) \>450 msec
* Participant has impaired renal function
* Alanine transaminase or AST are ≥2xULN (if liver metastases are present: ≥5xULN)
* Participant has moderate or severe cardiovascular disease
* Current or chronic history of liver disease or known hepatic or biliary abnormalities other than liver metastases