Trial to Evaluate the Safety and Preliminary Efficacy of GEN1079 in Participants With Advanced Solid Tumors

The purpose of this trial is to learn about the safety and effectiveness of the antibody GEN1079 in participants with certain types of cancer. The trial has multiple parts. The first part of the trial tests different doses of GEN1079 to find out if it is safe and determine what are the best doses to use. The second and third parts continue to test the safety of and whether GEN1079 works in additional participants with specific cancer types and at doses chosen based on results from the previous parts of the trial. For each participant, the trial will last approximately 33 to 67 weeks but this may vary for each person. This includes up to 21 days for screening prior to receiving trial treatment, approximately 6 to 12 weeks of treatment (the duration of treatment may vary for each participant), and approximately 24 to 52 weeks of follow up after trial treatment ends (the duration of follow up may vary for each participant). During the screening, tumor tissue either collected prior to this trial or freshly collected during screening will be provided by all participants. Participation in the trial will require visits to the site, with more frequent visits at the start of treatment and then less frequent visits afterwards. At site visits, there will be various tests (such as blood draws) and procedures (such as recording of heart activity, computed tomography \[CT\] scans) to monitor whether the treatment is safe and effective. All participants will receive active drug; no one will be given placebo.