Inclusion Criteria:

          -  Patient or legal guardian, if permitted by local regulatory authorities, provides
             informed consent to participate in the study must be performed before any procedure's
             protocol related

          -  age of ≥25 years old

          -  Performance Score ≥70 in accordance with the Karnofsky Performance Score (KPS),

          -  life expectancy period of at least 3 months on the screening day,

          -  Have measurable disease according to Response Evaluation Criteria in Solid Tumors
             Version 1.1 (RECIST v1.1)

          -  subject (or his/her partner) of childbearing potential willingness to use acceptable
             forms of contraception

          -  adequate blood, liver, renal and urine parameters

          -  phosphate levels within normal range

          -  HIV, HCV (hepatitis C virus) and HBV negative (hepatitis B virus),

          -  adequate cardiac function

        Inclusion Criteria Specific for parts:

        Part 1

          -  Patients with histologically confirmed advanced gastric cancer, bladder cancer,
             squamous lung cancer or non-small cell lung cancer with squamous immunophenotype,
             cholangiocarcinoma, sarcoma or endometrial cancer, be refractory to prior therapies
             and without effective further treatment options.

        Part 2 and 3

          -  Patients with histologically confirmed advanced gastric cancer, bladder cancer,
             squamous lung cancer or non-small cell lung cancer with squamous immunophenotype, be
             refractory to prior therapies and without effective further treatment options.

          -  Subject's archival formalin-fixed paraffin-embedded (FFPE) tumour sample available for
             molecular alteration diagnostics, and/or a possibility to collect a new biopsy.

          -  Present molecular alteration within FGFR 1, 2 or 3

        Exclusion Criteria:

          -  Any other current malignancy or malignancy diagnosed within the past five (5) years.

          -  Active brain metastases or leptomeningeal metastases.

          -  concurrent anticancer treatment within 28 days before the start of trial treatment;
             major surgery within 28 days before the start of trial treatment); use of blood
             transfusion within 7 days before the start of trial treatment,

          -  prior therapy with an agent directed to another FGFR inhibitor,

          -  pregnancy and/or breastfeeding,

          -  phosphate levels above the upper limit of normal,

          -  ectopic calcification/mineralization,

          -  endocrine alteration related to calcium/phosphate homeostasis e.g. parathyroid
             disorders, history of parathyroidectomy,

          -  concomitant therapies increasing calcium/phosphate serum levels,

          -  inability to take oral medicines,

          -  corneal disorder and/or keratopathy,

          -  persisting toxicity related to prior therapy Grade > 1 CTCAE v5.0, except
             polyneuropathy and alopecia,

          -  clinically significant (i.e., active) cardiovascular disease. History of abdominal
             fistula, bowel obstruction (Grade IV), gastrointestinal perforation, intra-abdominal
             abscess within 6 months of enrollment. Other significant diseases, which, in the
             opinion of the investigator, might impair the subject's tolerance of trial treatment.

          -  Receipt of any organ transplantation including allogeneic stem-cell transplantation.

        Exclusion Criteria Specific for parts:

        Part 2 and 3

          -  No FFPE tumour sample available to conduct FGFR alteration eligibility tests and no
             biopsy option.