Inclusion Criteria:

          -  Phase Ia part: advanced solid tumors or metastases including lymphoma localized in the
             head and neck region or thorax with an indication for fractionated palliative RT (Arm
             A); or treatment-naïve SCCHN eligible for fractionated curatively intended RT with
             concurrent cisplatin (Arm B)

          -  Phase Ib part: treatment-naïve Stage III A/B NSCLC not eligible for surgical resection
             or concurrent chemoradiation (Arm A expansion cohort) or treatment-naïve SCCHN
             eligible for fractionated curatively intended RT with concurrent cisplatin (Arm B
             expansion cohort)

          -  Ancillary cPoP Part: any tumor with at least 2 (sub)cutaneous tumor/metastases at
             least 2 cm apart which are RT naïve with an indication for high dose palliative RT

          -  Availability of archival tumor material, either as a block or slides (Phase Ia and
             Ib). If no archival material is available then a fresh biopsy should be taken

          -  Willing to have tumor biopsies collected in Ancillary cPoP

          -  Measurable or evaluable disease by RECIST v1.1 (not required for ancillary cPoP part
             of the study)

          -  Eastern Cooperative Oncology Group performance status (ECOG PS) ≤ 1

          -  Life expectancy of ≥ 3 months (Phase Ia, Arm A) or ≥ 6 months (Phase Ia, Arm B and
             Phase Ib)

          -  Female subjects of childbearing potential and male subjects with female partners of
             childbearing potential must be willing to avoid pregnancy.

        Exclusion Criteria:

          -  Chemotherapy, immunotherapy, hormonal therapy, biologic therapy, or any other
             anticancer therapy or investigational medicinal product (IMP) within 28 days of first
             trial drug intake for Phase Ia subjects, and any prior therapy for Phase Ib subjects.
             For subjects with rapidly growing tumors localized in the head and neck region or
             thorax where the treating physician cannot wait for 28 days, inclusion may take place
             if there is no residual toxicity from previous treatment (maximum CTCAE Grade 1)

          -  Prior RT to the same region within 12 months (Phase Ia, Arm A; subjects with tumors
             localized in the head and neck region or thorax) or at any time previously (Phase Ia,
             Arm B; treatment-naïve subjects with SCCHN and Phase Ib; treatment-naïve subjects with
             Stage III A/B NSCLC or SCCHN)

          -  Extensive prior RT on ≥30% of bone marrow reserve as judged by the investigator or
             prior bone marrow/stem cell transplantation within 5 years before trial start.

          -  Poor vital organ functions defined as:

               -  Bone marrow impairment as evidenced by hemoglobin <10.0 g/dL, neutrophil count
                  <1.0 × 109/L, platelets <100 × 109/L

               -  Renal impairment as evidenced by serum creatinine >1.5 × upper limit of normal
                  (ULN)

               -  Liver function abnormality as defined by total bilirubin >1.5 × ULN or aspartate
                  aminotransferase (AST)/alanine aminotransferase (ALT) >2.5 × ULN (except for
                  subjects with liver involvement, who can have AST/ALT >5 × ULN)

          -  History of difficulty swallowing, malabsorption or other chronic gastrointestinal
             disease or conditions that may hamper compliance and/or absorption of the IMP, use of
             percutaneous endoscopic gastrostomy (PEG) tubes

          -  Significant cardiac conduction abnormalities, including a history of long QTc syndrome
             and/or pacemaker, or impaired cardiovascular function such as New York Heart
             Association classification score >2.

          -  Subjects currently receiving (or unable to stop using prior to receiving the first
             dose of trial drug) medications or herbal supplements known to be potent inhibitors of
             cytochrome P450 (CYP)3A or CYP2C19 (must stop at least 1 week prior), potent inducers
             of CYP3A or CYP2C19 (must stop at least 3 weeks prior), or drugs mainly metabolized by
             CYP3A with a narrow therapeutic index (must stop at least one day prior).

          -  Subjects currently receiving H2-blocker or proton pump inhibitors (or unable to stop
             at least 5 days prior to the first treatment).

          -  If the planned radiation field includes any part of the esophagus and the subject has
             symptoms of ongoing esophagitis, the subject is not eligible, unless an esophageal
             endoscopy rules out the presence of esophagitis

          -  Subjects where more than 10% of the total esophagus volume receives more than 50% of
             the prescribed RT dose

        Main exclusion criteria for Ancillary Clinical Proof-of-Principle Part:

          -  History of difficulty swallowing, malabsorption or other chronic gastrointestinal
             disease or conditions that may hamper compliance and/or absorption of the IMP

          -  History of any other significant medical disease such as major gastric or small bowel
             surgery, recent drainage of significant volumes of ascites or pleural effusion (as per
             Investigator's judgement) or a psychiatric condition that might impair the subject's
             well-being or preclude full participation in the trial

          -  Subjects currently receiving (or unable to stop using prior to receiving the first
             dose of study drug) medications or herbal supplements known to be potent inhibitors of
             CYP3A or CYP2C19 must stop at least 1 week prior to taking MSC2490484A. Subjects
             receiving potent inducers of CYP3A or CYP2C19 must stop at least 3 weeks prior to
             taking MSC2490484A. Those receiving drugs mainly metabolized by CYP3A with a narrow
             therapeutic index as judged by the Investigator (and after optional consultation with
             the Sponsor) must stop at least one day prior to taking MSC2490484A.