Inclusion Criteria:

          -  Signed informed consent

          -  Male or female subjects ≥ 18 years of age

          -  ECOG PS (Eastern Cooperative Oncology Group Performance Status) of 0 or 1

          -  Patients with advanced malignant epithelioid mesothelioma or advanced recurrent serous
             ovarian cancer, who have exhausted available therapeutic options; in addition, in the
             dose expansion part of the study, patients with metastatic pancreatic adenocarcinoma,
             who have exhausted available therapeutic options

          -  Availability of fresh or archival tumor tissue samples

          -  Adequate bone marrow, liver and renal function, as assessed by pre-defined laboratory
             requirements (within 28 days before start of study drug treatment)

          -  A negative serum pregnancy test in women of childbearing potential (WOCBP) performed
             within 7 days before the start of study drug administration. Women and men of
             reproductive potential must agree to use highly effective methods of contraception,
             when sexually active.

        Exclusion Criteria:

          -  Impaired cardiac function, clinically significant cardiac disease or cardiac
             arrhythmias

          -  Pericarditis (any CTCAE grade) or pericardial effusion (CTCAE Grade ≥ 2)

          -  Left Ventricular Ejection Fraction (LVEF) < 50% (as measured at screening by
             echocardiogram).

          -  History of anaphylactic reactions to monoclonal antibody therapy

          -  History of Myelodysplastic syndrome (MDS)/treatment-related acute myeloid leukemia
             (t-AML) or with features suggestive of MDS/AML

          -  Infections of CTCAE (Common Terminology Criteria for Adverse Events) version 5.0 Grade
             2 not responding to therapy or active clinically serious infections of CTCAE Grade >2;
             known human immunodeficiency virus (HIV) infection; active hepatitis B virus (HBV) or
             hepatitis C virus (HCV)infection requiring treatment. Patients with chronic HBV or HCV
             infection are eligible at the investigator's discretion provided that the disease is
             stable and sufficiently controlled under treatment

          -  Known brain, spinal or meningeal metastases