This Study Aims to Find the Best Dose of BI 907828 (Brigimadlin) in Patients With Different Types of Advanced Cancer (Solid Tumors)

Inclusion Criteria: * Provision of signed and dated, written informed consent form ICF in accordance with ICH-GCP and local legislation prior to any trial-specific procedures, sampling, or analyses. * Pathologically documented, advanced solid tumors. * Patients fulfilling one or more of the following criteria: * Radiologically documented disease progression or relapse * Patients who are not eligible to receive standard of care treatments, and for whom no proven treatments exist. * Patients with MDM2 amplified sarcomas who require first line treatment (for Ph Ib/dose expansion - Cohort 1 only). * Patients with MDM2 amplified sarcomas may fulfil any one of the above three criteria to be considered eligible. * Phase Ia (dose escalation) only: * Patient has a tumor with either a known TP53 wild type status, or unknown TP53 status, and regardless of MDM2 amplification status, at the time of study entry. * Phase Ib (expansion phase) only: * Cohort 1: TP53 wt and MDM2-amplified sarcoma with advanced/metastatic disease at any line of therapy. If TP53 status is not available during screening, the patient may be included with unknown TP53 status if a tissue sample is submitted for central laboratory assessment. If TP53 status cannot be evaluated, the patient may be included if agreed between the Investigator and Sponsor. * Cohort 2: TP53 wt and MDM2- amplified NSCLC, urothelial, gastric, biliary tract (including cholangiocarcinoma, intra- and extrahepatic biliary tree, gall blander and ampulla of vater) or pancreatic solidPDAC tumors who have had at least one previous line of therapy for advanced/metastatic disease. If TP53 status cannot be evaluated the patient may be included if agreed between the Investigator and Sponsor * Phase Ia (dose escalation) only: * Patient with either measurable or non-measurable disease. * Non-evaluable disease allowed. * Phase Ib (expansion phase) only: * At least one target lesion that can be accurately measured per RECIST v.1.1. * Phase Ia: * Patient must be willing to undergo blood sampling for PK, pharmacodynamic, biomarker, and PGx analyses. * Phase Ib: * Patient must be willing to undergo tumor biopsy sampling for pharmacodynamic analyses and blood sampling for PK, pharmacodynamics, and biomarker analyses. * Willingness to provide a fresh tumor tissue sample obtained after relapse/ progression during or after prior therapy. In case a fresh biopsy cannot be obtained (e.g. inaccessible lesions or patient safety concern), an archived specimen, collected before screening within 12 months of enrollment, may be submitted. If these requirements cannot be met, then the patient may be allowed to enter the study at Sponsor discretion, after agreement between the Investigator and Sponsor. * Further inclusion criteria apply Exclusion Criteria: * Previous administration of BI 907828 (brigimadlin) or any other MDM2-p53 or MDMX (MDM4)-p53 antagonist. * Known TP53 mutant tumor. * Symptomatic metastases from non-brain tumors. Note: Patients with previously treated brain metastases may participate provided they are stable, without evidence of progression by imaging (using the identical imaging modality for each assessment, either MRI or computed tomography (CT) scan), for at least four weeks prior to the first dose of trial treatment, and any neurologic symptoms have returned to baseline; have no evidence of new or enlarging brain metastases. Patients on corticosteroids must have a stable dose for at least 5 days prior to baseline MRI. * Patients with history of bleeding diathesis. * Major surgery (major according to the Investigator's assessment) performed within 12 weeks prior to start of study treatment, or planned within 12 months after screening (e.g. hip replacement). * Any other documented active or suspected malignancy or history of malignancy within 3 years prior to screening, except appropriately treated basal cell carcinoma of the skin or in situ carcinoma of uterine cervix, or other local tumors considered cured by local treatment. * Patients who must or wish to continue the intake of restricted medications or any drug considered likely to interfere with the safe conduct of the trial. * Further exclusion criteria apply.